(BQ) Part 2 book Fox - Human physiology presents the following contents: Blood, heart and circulation; cardiac output, blood flow and blood pressure, the immune system, respiratory physiology, physiology of the kidneys, the digestive system, regulation of metabolism, reproduction.
CHAPTER 13 Blood, Heart, and Circulation C H A P TE R O UTLI N E 13.1 Functions and Components of the Circulatory System 405 Functions of the Circulatory System 405 Major Components of the Circulatory System 405 13.2 Composition of the Blood 406 Plasma 406 The Formed Elements of Blood 407 Hematopoiesis 409 Red Blood Cell Antigens and Blood Typing 412 Blood Clotting 414 Dissolution of Clots 417 13.3 Structure of the Heart 418 Pulmonary and Systemic Circulations 418 Atrioventricular and Semilunar Valves 419 Heart Sounds 420 13.4 Cardiac Cycle 422 Pressure Changes During the Cardiac Cycle 423 13.5 Electrical Activity of the Heart and the Electrocardiogram 425 Electrical Activity of the Heart 425 The Electrocardiogram 428 13.6 Blood Vessels 431 Refresh Your Memory Before you begin this chapter, you may want to review these concepts from previous chapters: ■ Action Potentials 174 ■ Functions of the Autonomic Nervous System 251 ■ Mechanisms of Contraction 363 ■ Cardiac and Smooth Muscle 391 Arteries 431 Capillaries 433 Veins 435 13.7 Atherosclerosis and Cardiac Arrhythmias 436 Atherosclerosis 436 Arrhythmias Detected by the Electrocardiograph 440 13.8 Lymphatic System 442 Summary 445 Review Activities 447 404 Blood, Heart, and Circulation Clinical Investigation Jessica went to her physician complaining of fatigue and mentioned that she had been experiencing heavier menstruations over the past several months He mentioned that she had mitral valve prolapse, but didn’t think that was the cause of her fatigue and advised her take more iron in her diet while they waited for the blood test results However, a subsequent ECG revealed that she had atrial fibrillation, which he said might also explain her fatigue The physician prescribed a drug called rivaroxaban, and told Jessica that she should perhaps exercise more moderately and that she should definitely stop smoking Some of the new terms and concepts you will encounter include: • Anemia, blood clotting factors, heart valves and heart sounds • Electrocardiogram and heart arrhythmias • Atherosclerosis, thrombosis, and cardiovascular diseases 13.1 FUNCTIONS AND COMPONENTS OF THE CIRCULATORY SYSTEM Blood serves numerous functions, including the transport of respiratory gases, nutritive molecules, metabolic wastes, and hormones Blood travels through the body in a system of vessels leading from and returning to the heart LEARNING OUTCOMES After studying this section, you should be able to: Identify the functions and components of the circulatory system Describe the relationship between interstitial fluid, plasma, and lymph A unicellular organism can provide for its own maintenance and continuity by performing the wide variety of functions needed for life By contrast, the complex human body is composed of specialized cells that depend on one another Because most are firmly implanted in tissues, their oxygen and nutrients must be brought to them, and their waste products removed Therefore, a highly effective means of transporting materials within the body is needed The blood serves this transportation function An estimated 60,000 miles of vessels throughout the body of an adult ensure that continued sustenance reaches each of the trillions of living cells But the blood can also transport disease-causing viruses, bacteria, and their toxins To guard against this, the circulatory system has protective mechanisms—the white blood cells and the lymphatic system In order to perform its various functions, the circulatory system works together with the respiratory, 405 urinary, digestive, endocrine, and integumentary systems in maintaining homeostasis Functions of the Circulatory System The functions of the circulatory system can be divided into three broad areas: transportation, regulation, and protection Transportation All of the substances essential for cellular metabolism are transported by the circulatory system These substances can be categorized as follows: a Respiratory Red blood cells, or erythrocytes, transport oxygen to the cells In the lungs, oxygen from the inhaled air attaches to hemoglobin molecules within the erythrocytes and is transported to the cells for aerobic respiration Carbon dioxide produced by cell respiration is carried by the blood to the lungs for elimination in the exhaled air b Nutritive The digestive system is responsible for the mechanical and chemical breakdown of food so that it can be absorbed through the intestinal wall into the blood and lymphatic vessels The blood then carries these absorbed products of digestion through the liver to the cells of the body c Excretory Metabolic wastes (such as urea), excess water and ions, and other molecules not needed by the body are carried by the blood to the kidneys and excreted in the urine Regulation The circulatory system contributes to both hormonal and temperature regulation a Hormonal The blood carries hormones from their site of origin to distant target tissues where they perform a variety of regulatory functions b Temperature Temperature regulation is aided by the diversion of blood from deeper to more superficial cutaneous vessels or vice versa When the ambient temperature is high, diversion of blood from deep to superficial vessels helps cool the body; when the ambient temperature is low, the diversion of blood from superficial to deeper vessels helps keep the body warm Protection The circulatory system protects against blood loss from injury and against pathogens, including foreign microbes and toxins introduced into the body a Clotting The clotting mechanism protects against blood loss when vessels are damaged b Immune The immune function of the blood is performed by the leukocytes (white blood cells) that protect against many disease-causing agents (pathogens) Major Components of the Circulatory System The circulatory system consists of two subdivisions: the cardiovascular system and the lymphatic system The cardiovascular system consists of the heart and blood vessels, and the lymphatic system, which includes lymphatic vessels and lymphoid tissues within the spleen, thymus, tonsils, and lymph nodes The heart is a four-chambered double pump Its pumping action creates the pressure head needed to push blood through 406 Chapter 13 the vessels to the lungs and body cells At rest, the heart of an adult pumps about liters of blood per minute At this rate, it takes about minute for blood to be circulated to the most distal extremity and back to the heart Blood vessels form a tubular network that permits blood to flow from the heart to all the living cells of the body and then back to the heart Arteries carry blood away from the heart, whereas veins return blood to the heart Arteries and veins are continuous with each other through smaller blood vessels Arteries branch extensively to form a “tree” of progressively smaller vessels The smallest of the arteries are called arterioles Blood passes from the arterial to the venous system in microscopic capillaries, which are the thinnest and most numerous of the blood vessels All exchanges of fluid, nutrients, and wastes between the blood and tissues occur across the walls of capillaries Blood flows through capillaries into microscopic veins called venules, which deliver blood into progressively larger veins that eventually return the blood to the heart As blood plasma (the fluid portion of the blood) passes through capillaries, the hydrostatic pressure of the blood forces some of this fluid out of the capillary walls Fluid derived from plasma that passes out of capillary walls into the surrounding tissues is called tissue fluid, or interstitial fluid Some of this fluid returns directly to capillaries, and some enters into lymphatic vessels located in the connective tissues around the blood vessels Fluid in lymphatic vessels is called lymph This fluid is returned to the venous blood at specific sites Lymph nodes, positioned along the way, cleanse the lymph prior to its return to the venous blood The lymphatic system is thus considered a part of the circulatory system and is discussed in section 13.8 | CHECKPOINT 1a State the components of the circulatory system that function in oxygen transport, in the transport of nutrients from the digestive system, and in protection 1b Describe the functions of arteries, veins, and capillaries Define the terms interstitial fluid and lymph How these fluids relate to blood plasma? Figure 13.1 The constituents of blood Blood cells become packed at the bottom of the test tube when whole blood is centrifuged, leaving the fluid plasma at the top of the tube Red blood cells are the most abundant of the blood cells—white blood cells and platelets form only a thin, light-colored “buffy coat” at the interface between the packed red blood cells and the plasma 13.2 COMPOSITION OF THE BLOOD Blood consists of formed elements that are suspended and carried in a fluid called plasma The formed elements— erythrocytes, leukocytes, and platelets—function respectively in oxygen transport, immune defense, and blood clotting LEARNING OUTCOMES After studying this section, you should be able to: Distinguish between the different formed elements of the blood Describe the regulation of red and white blood cell production Explain blood typing and blood clotting The total blood volume in the average-size adult is about liters, constituting about 8% of the total body weight Blood leaving the heart is referred to as arterial blood Arterial blood, with the exception of that going to the lungs, is bright red because of a high concentration of oxyhemoglobin (the combination of oxygen and hemoglobin) in the red blood cells Venous blood is blood returning to the heart Except for the venous blood from the lungs, it contains less oxygen and is therefore a darker red than the oxygen-rich arterial blood Blood is composed of a cellular portion, called formed elements, and a fluid portion, called plasma When a blood sample is centrifuged, the heavier formed elements are packed into the bottom of the tube, leaving plasma at the top (fig. 13.1) The formed elements constitute approximately 45% of the total blood volume, and the plasma accounts for the remaining 55% Red blood cells compose most of the formed elements; the percentage of red blood cell volume to total blood volume in a centrifuged blood sample (a measurement called the hematocrit) is 36% to 46% in women and 41% to 53% in men (table 13.1) Plasma Plasma is a straw-colored liquid consisting of water and dissolved solutes The major solute of the plasma in terms of its Centrifuged Blood Sample Blood Smear Blood plasma Platelets “Buffy coat” Formed elements Red blood cells White blood cells Blood, Heart, and Circulation Table 13.1 | Representative Normal Plasma Values Measurement Normal Range Blood volume 80–85 ml/kg body weight Blood osmolality 285–295 mOsm Blood pH 7.38–7.44 Enzymes Creatine phosphokinase (CPK) Female: 10–79 U/L Male: 17–148 U/L Lactic dehydrogenase (LDH) 45–90 U/L Phosphatase (acid) Female: 0.01–0.56 Sigma U/ml Male: 0.13–0.63 Sigma U/ml Hematology Values Hematocrit Female: 36%–46% Male: 41%–53% Hemoglobin Female: 12–16 g/100 ml Male: 13.5–17.5 g/100 ml Red blood cell count 4.50–5.90 million/mm3 White blood cell count 4,500–11,000/mm3 Hormones Testosterone 407 concentration is Na1 In addition to Na1, plasma contains many other ions, as well as organic molecules such as metabolites, hormones, enzymes, antibodies, and other proteins The concentrations of some of these plasma constituents are shown in table 13.1 Plasma Proteins Plasma proteins constitute 7% to 9% of the plasma The three types of proteins are albumins, globulins, and fibrinogen Albumins account for most (60% to 80%) of the plasma proteins and are the smallest in size They are produced by the liver and provide the osmotic pressure needed to draw water from the surrounding tissue fluid into the capillaries This action is needed to maintain blood volume and pressure Globulins are grouped into three subtypes: alpha globulins, beta globulins, and gamma globulins The alpha and beta globulins are produced by the liver and function in transporting lipids and fatsoluble vitamins Gamma globulins are antibodies produced by lymphocytes (one of the formed elements found in blood and lymphoid tissues) and function in immunity Fibrinogen, which accounts for only about 4% of the total plasma proteins, is an important clotting factor produced by the liver During the process of clot formation (described later in this section), fibrinogen is converted into insoluble threads of fibrin Thus, the fluid from clotted blood, called serum, does not contain fibrinogen but is otherwise identical to plasma Male: 270–1,070 ng/100 ml Female: 6–86 ng/100 ml Plasma Volume Adrenocorticotrophic hormone (ACTH) 6–76 pg/ml Growth hormone Children: over 10 ng/ml A number of regulatory mechanisms in the body maintain homeostasis of the plasma volume If the body should lose water, the remaining plasma becomes excessively concentrated—its osmolality (chapter 6) increases This is detected by osmoreceptors in the hypothalamus, resulting in a sensation of thirst and the release of antidiuretic hormone (ADH) from the posterior pituitary (chapter 11, section 11.3) This hormone promotes water retention by the kidneys, which—together with increased intake of fluids—helps compensate for the dehydration and lowered blood volume This regulatory mechanism, together with others that influence plasma volume, are very important in maintaining blood pressure (chapter 14, section 14.6) Adult male: below ng/ml Insulin 2–20 μU/ml (fasting) Ions Bicarbonate 24–30 mmol/l Calcium 9.0–10.5 mg/dl Chloride 98–106 mEq/L Potassium 3.5–5.0 mEq/L Sodium 135–145 mEq/L The Formed Elements of Blood Organic Molecules (Other) Cholesterol, desirable under 200 mg/dl Glucose 75–115 mg/dl (fasting) Lactic acid 5–15 mg/dl Protein (total) 5.5–8.0 g/dl Triglyceride under 160 mg/dl Urea nitrogen 10–20 mg/dl Uric acid Male 2.5–8.0 mg/dl Female 1.5–6.0 mg/dl Source: Excerpted from material appearing in The New England Journal of Medicine, “Case Records of the Massachusetts General Hospital,” 302:37–38, 314:39–49, 351:1548–1563 1980, 1986, 2004 The formed elements of blood include two types of blood cells: erythrocytes, or red blood cells, and leukocytes, or white blood cells Erythrocytes are by far the more numerous of the two A cubic millimeter of blood normally contains 5.1 million to 5.8 million erythrocytes in males and 4.3 million to 5.2 million erythrocytes in females By contrast, the same volume of blood contains only 5,000 to 9,000 leukocytes Erythrocytes Erythrocytes are flattened, biconcave discs about 7 mm in diameter and 2.2 mm thick Their unique shape relates to their function of transporting oxygen; it provides an increased 408 Chapter 13 surface area through which gas can diffuse (fig. 13.2) Erythrocytes lack nuclei and mitochondria (they obtain energy through anaerobic metabolism) Partly because of these deficiencies, erythrocytes have a relatively short circulating life span of only about 120 days Older erythrocytes are removed from the circulation by phagocytic cells in the liver, spleen, and bone marrow Each erythrocyte contains approximately 280 million hemoglobin molecules, which give blood its red color Each hemoglobin molecule consists of four protein chains called globins, each of which is bound to one heme, a red-pigmented molecule that contains iron The iron group of heme is able to combine with oxygen in the lungs and release oxygen in the tissues The heme iron is recycled from senescent (old) red blood cells (see chapter 18, fig 18.22) by phagocytes in the liver and spleen This iron travels in the blood to the bone marrow attached to a protein carrier called transferrin This recycled heme iron supplies most of the body’s need for iron The balance of the requirement for iron, though relatively small, must be made up for in the diet Dietary iron is absorbed mostly in the duodenum (the first part of the small intestine) and transported from the intestine bound to transferrin in the blood The transferrin with its bound iron is taken out of the blood by cells of the bone marrow and liver by endocytosis, which is triggered by binding of transferrin to its membrane receptors Although the bone marrow produces about 200 billion red blood cells each day, and erythrocytes contain about to g of iron, we normally need only a small amount of iron in the diet to compensate for the small amount lost from the body However, if there is a dietary iron deficiency that reduces the ability of the bone marrow to produce hemoglobin, an iron-deficiency anemia may result Anemia can also result from a deficiency in vitamin B12 due to lack of a stomach secretion called intrinsic factor (discussed in the next Clinical Application box) Figure 13.2 A colorized scanning electron micrograph of red blood cells The shape of the red blood cells is described as a “biconcave disc.” In reality, individual red blood cells not look red when viewed under a microscope C L I N I C A L A P P L I C AT I O N Iron-deficiency anemia, the most common form of anemia (low red blood cell and/or hemoglobin concentration), results when there is insufficient iron for the production of normal amounts of hemoglobin This is most often caused by blood loss due to heavy menstruation, peptic ulcers, or other sources of bleeding in the gastrointestinal tract It can also be caused by the inability of absorb iron (in celiac disease, for example) or from pregnancy due to the requirements of the fetus Pernicious anemia is due to a lack of intrinsic factor, a molecule produced by the stomach epithelium and needed for the intestinal absorption of vitamin B12 (which is required for hemoglobin production) This can result from autoimmune attack of the gastric epithelium The most serious anemia is aplastic anemia, produced by damage to the bone marrow from a variety of causes, including radiation and chemotherapy for cancer Clinical Investigation CLUES Jessica experienced heavy menstruations and fatigue, and her blood was tested • How might heavy menstruation and fatigue be related? • How might a blood test help to diagnose the cause of Jessica’s fatigue? Leukocytes Leukocytes differ from erythrocytes in several respects Leukocytes contain nuclei and mitochondria and can move in an amoeboid fashion Because of their amoeboid ability, leukocytes can squeeze through pores in capillary walls and move to a site of infection, whereas erythrocytes usually remain confined within blood vessels The movement of leukocytes through capillary walls is referred to as diapedesis or extravasation White blood cells are almost invisible under the microscope unless they are stained; therefore, they are classified according to their staining properties Those leukocytes that have granules in their cytoplasm are called granular leukocytes; those without clearly visible granules are called agranular (or nongranular) leukocytes The stain used to identify white blood cells is usually a mixture of a pink-to-red stain called eosin and a blue-to-purple stain (methylene blue), which is called a “basic stain.” Granular leukocytes with pink-staining granules are therefore called eosinophils, and those with blue-staining granules are called basophils Those with granules that have little affinity for either stain are neutrophils (fig. 13.3) Neutrophils are the most abundant type of leukocyte, accounting for 50% to 70% of the leukocytes in the blood Immature neutrophils have sausage-shaped nuclei and are called band cells As the band cells mature, their Blood, Heart, and Circulation Neutrophils Lymphocytes Eosinophils Monocytes Basophils Platelets Erythrocytes Figure 13.3 The blood cells and platelets The white blood cells depicted above are granular leukocytes; the lymphocytes and monocytes are nongranular leukocytes nuclei become lobulated, with two to five lobes connected by thin strands At this stage, the neutrophils are also known as polymorphonuclear leukocytes (PMNs) There are two types of agranular leukocytes: lymphocytes and monocytes Lymphocytes are usually the second most numerous type of leukocyte; they are small cells with round nuclei and little cytoplasm Monocytes, by contrast, are the largest of the leukocytes and generally have kidney- or horseshoe-shaped nuclei In addition to these two cell types, there are smaller numbers of plasma cells, which are derived from lymphocytes Plasma cells produce and secrete large amounts of antibodies The immune functions of the different white blood cells are described in more detail in chapter 15 C L I N I C A L A P P L I C AT I O N Whereas anemia refers to an abnormally low red blood cell count (as previously discussed), polycythemia is an abnormally high red blood cell count This can have many causes, including the low oxygen of life at high altitudes (discussed in chapter 16) Leukopenia is an abnormally low white blood cell count, which may be produced by radiation for cancer, among other causes Leukocytosis is the opposite—an abnormally high white blood cell count, which may be caused by cytokines released from an inflammation during an infection Leukemia is cancer of the bone marrow that causes a high number of abnormal and immature white blood cells to appear in the blood Platelets Platelets, or thrombocytes, are the smallest of the formed elements and are actually fragments of large cells called megakaryocytes, which are found in bone marrow (This is why the 409 term formed elements is used instead of blood cells to describe erythrocytes, leukocytes, and platelets.) The fragments that enter the circulation as platelets lack nuclei but, like leukocytes, are capable of amoeboid movement The platelet count per cubic millimeter of blood ranges from 130,000 to 400,000, but this count can vary greatly under different physiological conditions Platelets survive for about five to nine days before being destroyed by the spleen and liver Platelets play an important role in blood clotting They constitute most of the mass of the clot, and phospholipids in their cell membranes activate the clotting factors in plasma that result in threads of fibrin, which reinforce the platelet plug Platelets that attach together in a blood clot release serotonin, a chemical that stimulates constriction of blood vessels, thus reducing the flow of blood to the injured area Platelets also secrete growth factors (autocrine regulators—chapter 11, section 11.7), which are important in maintaining the integrity of blood vessels These regulators also may be involved in the development of atherosclerosis, as described in section 13.7 The formed elements of the blood are illustrated in figure 13.3, and their characteristics are summarized in table 13.2 Hematopoiesis Blood cells are constantly formed through a process called hematopoiesis (also called hemopoiesis) The hematopoietic stem cells—those that give rise to blood cells—originate in the yolk sac of the human embryo and then migrate in sequence to regions around the aorta, to the placenta, and then to the liver of a fetus The liver is the major hematopoietic organ of the fetus, but then the stem cells migrate to the bone marrow and the liver ceases to be a source of blood cell production shortly after birth Scientists estimate that the hematopoietic tissue of the bone marrow produces about 500 billion cells each day The hematopoietic stem cells form a population of relatively undifferentiated, multipotent adult stem cells (chapter 20, section 20.6) that give rise to all of the specialized blood cells The hematopoietic stem cells are self-renewing, duplicating themselves by mitosis so that the parent stem cell population will not become depleted as individual stem cells differentiate into the mature blood cells Hematopoietic stem cells are rare, but they proliferate in response to the proinflammatory cytokines released during infection (chapter 15, section 15.3) and in response to the depletion of leukocytes during infection Hematopoietic stem cells are the only cells capable of restoring complete hematopoietic ability (producing all blood cell lines) upon transplantation into the depleted bone marrow of a recipient The term erythropoiesis refers to the formation of erythrocytes, and leukopoiesis to the formation of leukocytes These processes occur in two classes of tissues after birth, myeloid and lymphoid Myeloid tissue is the red bone marrow of the long bones, ribs, sternum, pelvis, bodies of the vertebrae, and portions of the skull Lymphoid tissue includes the lymph nodes, tonsils, spleen, and thymus The bone marrow produces all of the different types of blood cells; the lymphoid tissue produces lymphocytes derived from cells that originated in the bone marrow 410 Chapter 13 Table 13.2 | Formed Elements of the Blood Component Description Number Present Function Erythrocyte (red blood cell) Biconcave disc without nucleus; contains hemoglobin; survives 100 to 120 days 4,000,000 to 6,000,000 / mm3 Transports oxygen and carbon dioxide 5,000 to 10,000 / mm3 Aid in defense against infections by microorganisms Leukocytes (white blood cells) Granulocytes About twice the size of red blood cells; cytoplasmic granules present; survive 12 hours to days Neutrophil Nucleus with to lobes; cytoplasmic granules stain slightly pink 54% to 62% of white cells present Phagocytic Eosinophil Nucleus bilobed; cytoplasmic granules stain red in eosin stain 1% to 3% of white cells present Helps to detoxify foreign substances; secretes enzymes that dissolve clots; fights parasitic infections Basophil Nucleus lobed; cytoplasmic granules stain blue in hematoxylin stain Less than 1% of white cells present Releases anticoagulant heparin Agranulocytes Cytoplasmic granules not visible; survive 100 to 300 days (some much longer) Monocyte to times larger than red blood cell; nuclear shape varies from round to lobed 3% to 9% of white cells present Phagocytic Lymphocyte Only slightly larger than red blood cell; nucleus nearly fits cell 25% to 33% of white cells present Provides specific immune response (including antibodies) Cytoplasmic fragment; survives to days 130,000 to 400,000 / mm3 Enables clotting; releases serotonin, which causes vasoconstriction Platelet (thrombocyte) As the cells become differentiated during erythropoiesis and leukopoiesis, they develop membrane receptors for chemical signals that cause further development along particular lines The earliest cells that can be distinguished under a microscope are the erythroblasts (which become erythrocytes), myeloblasts (which become granular leukocytes), lymphoblasts (which form lymphocytes), and monoblasts (which form monocytes) Erythropoiesis is an extremely active process It is estimated that about 2.5 million erythrocytes are produced every second in order to replace those that are continuously destroyed by the spleen and liver The life span of an erythrocyte is approximately 120 days Agranular leukocytes remain functional for 100 to 300 days under normal conditions Granular leukocytes, by contrast, have an extremely short life span of 12 hours to days The production of different subtypes of leukocytes is stimulated by chemicals called cytokines These are autocrine regulators secreted by various cells of the immune system The production of red blood cells is stimulated by the hormone erythropoietin, which is secreted by the kidneys The gene for erythropoietin has been commercially cloned so that this hormone is now available for treatment of anemia, including the anemia that results from kidney disease in patients undergoing dialysis Injections with recombinant erythropoietin significantly improve aerobic physical performance, probably because of increased hemoglobin allowing the blood to carry an increased amount of oxygen The World Anti-Doping Code bans the use of recombinant erythropoietin for this reason, and urine from athletes is tested for erythropoietin by World Anti-Doping Agency (WADA) laboratories Scientists have identified a specific cytokine that stimulates proliferation of megakaryocytes and their maturation into platelets By analogy with erythropoietin, they named this regulatory molecule thrombopoietin The gene that codes for thrombopoietin C L I N I C A L A P P L I C AT I O N Thrombocytosis is an abnormally elevated platelet count This occurs when conditions such as acute blood loss, inflammation, cancer, and others stimulate the liver to produce an excess of thrombopoietin However, the production of thrombopoietin is normally adjusted to maintain homeostasis of the platelet count Because both megakaryocytes in the bone marrow and circulating platelets have receptors that bind to thrombopoietin, a decrease in platelets makes more thrombopoietin available to stimulate the megakaryocytes, raising the platelet count Conversely, an increase in the number of platelets results in less thrombopoietin that is free to enter the bone marrow and stimulate the megakaryocytes, reducing the platelet count to normal Blood, Heart, and Circulation also has been cloned, so that recombinant thrombopoietin is now available for medical research and applications In clinical trials, thrombopoietin has been used to treat the thrombocytopenia (low platelet count) that occurs as a result of bone marrow depletion in patients undergoing chemotherapy for cancer 411 Hemocytoblast (stem cell) Regulation of Leukopoiesis A variety of cytokines stimulate different stages of leukocyte development The cytokines known as multipotent growth factor-1, interleukin-1, and interleukin-3 have general effects, stimulating the development of different types of white blood cells Granulocyte colony-stimulating factor (G-CSF) acts in a highly specific manner to stimulate the development of neutrophils, whereas granulocyte-monocyte colony-stimulating factor (GM-CSF) stimulates the development of monocytes and eosinophils The genes for the cytokines G-CSF and GM-CSF have been cloned, making these cytokines available for medical applications Proerythroblast Stimulated by erythropoietin Erythroblast In bone marrow (myeloid tissue) C L I N I C A L A P P L I C AT I O N Hematopoietic stem cell transplants help to restore bone marrow function when the bone marrow stem cell population has been depleted because of chemotherapy or radiation therapy for cancer, or from other causes These stem cells can be obtained from aspiration of the marrow from the iliac crest, but are now more commonly obtained from peripheral blood after the person has been injected with G-CSF and GM-CSF, which stimulate the marrow to release more stem cells Autologous transplants are obtained from the same patient (before treatments that deplete the bone marrow), whereas allogeneic transplants are obtained from a different person, usually a sibling or someone else who is genetically closely matched Normoblast Nucleus expelled Reticulocyte Erythrocytes Released into blood Regulation of Erythropoiesis The primary regulator of erythropoiesis is erythropoietin, produced by the kidneys in response to tissue hypoxia when the blood oxygen levels are decreased One of the possible causes of decreased blood oxygen levels is a decreased red blood cell count Because of erythropoietin stimulation, the daily production of new red blood cells compensates for the daily destruction of old red blood cells, preventing a decrease in the blood oxygen content An increased secretion of erythropoietin and production of new red blood cells occurs when a person is at a high altitude or has lung disease, which are conditions that reduce the oxygen content of the blood Erythropoietin acts by binding to membrane receptors on cells that will become erythroblasts (fig. 13.4) The erythropoietin-stimulated cells undergo cell division and differentiation, leading to the production of erythroblasts These are transformed into normoblasts, which lose their nuclei to become reticulocytes The reticulocytes then change into fully mature erythrocytes This process takes days; the reticulocyte Figure 13.4 The stages of erythropoiesis The proliferation and differentiation of cells that will become mature erythrocytes (red blood cells) occurs in the bone marrow and is stimulated by the hormone erythropoietin, secreted by the kidneys normally stays in the bone marrow for the first days and then circulates in the blood on the third day At the end of the erythrocyte life span of 120 days, the old red blood cells are removed by the liver and by macrophages (phagocytic cells) of the spleen and bone marrow Most of the iron contained in the hemoglobin molecules of the destroyed red blood cells is recycled back to the myeloid tissue to be used in the production of hemoglobin for new red blood cells (see chapter 18, fig 18.22) The production of red blood cells and synthesis of hemoglobin depends on the supply of iron, along with that of vitamin B12 and folic acid 412 Chapter 13 Iron in food is absorbed in the duodenum (first region of the small intestine) and passes into enterocytes (intestinal epithelial cells), where it can be either stored or secreted into the plasma through ferroportin membrane channels Similarly, the iron derived from the heme in old red blood cells that were destroyed by macrophages can be stored in the macrophages or released into the blood through ferroportin channels Iron travels in the blood is bound to a plasma protein called transferrin, where it may be used by the bone marrow in erythropoiesis or stored, primarily in the liver Iron is eliminated from the body only by the shedding of intestinal epithelial cells and through menstruation Thus, the intestinal absorption of iron must be highly regulated so that only the amount needed to maintain iron homeostasis is absorbed The major regulator of iron homeostasis is hepcidin, a polypeptide hormone secreted by the liver Hepcidin acts on the enterocytes of the small intestine and the macrophages where iron is stored to cause the ferroportin channels to be removed from the plasma membrane and destroyed Hepcidin thereby inhibits the intestinal absorption of iron and the release of iron from cellular storage, lowering the plasma iron concentration This completes a negative feedback loop in which the liver’s production of hepcidin is decreased by iron deficiency and most anemias, and increased by excessive iron intake Because the dietary requirements for iron are quite small, iron-deficiency anemia in adults is usually due not to a dietary deficiency but rather to blood loss, which reduces the amount of iron that can be recycled The normal dietary requirement for men is about 10 mg/day, whereas women with average menstrual blood loss need about 15 mg/day and pregnant women require about 30 mg/day Red Blood Cell Antigens and Blood Typing There are certain molecules on the surfaces of all cells in the body that can be recognized as foreign by the immune system of another individual These molecules are known as antigens As part of the immune response, particular lymphocytes secrete a class of proteins called antibodies that bond in a specific fashion with antigens The specificity of antibodies for antigens is analogous to the specificity of enzymes for their substrates, and of receptor proteins for neurotransmitters and hormones A complete description of antibodies and antigens is provided in chapter 15 ABO System The distinguishing antigens on other cells are far more varied than the antigens on red blood cells Red blood cell antigens, however, are of extreme clinical importance because their types must be matched between donors and recipients for blood transfusions There are several groups of red blood cell antigens, but the major group is known as the ABO system In terms of the antigens present on the red blood cell surface, a person may be type A (with only A antigens), type B (with only B antigens), type AB (with both A and B antigens), or type O (with neither A nor B antigens) Each person’s blood type—A, B, or O—denotes the antigens present on the red blood cell surface, which are the products of the genes (located on chromosome number 9) that code for these antigens Each person inherits two genes (one from each parent) that control the production of the ABO antigens The genes for A or B antigens are dominant to the gene for O The O gene is recessive, simply because it doesn’t code for either the A or the B red blood cell antigens The genes for A and B are often shown as IA and IB, and the recessive gene for O is shown as the lower-case i A person who is type A, therefore, may have inherited the A gene from each parent (may have the genotype IAIA), or the A gene from one parent and the O gene from the other parent (and thus have the genotype IAi) Likewise, a person who is type B may have the genotype IBIB or IBi It follows that a type O person inherited the O gene from each parent (has the genotype ii), whereas a type AB person inherited the A gene from one parent and the B gene from the other (there is no dominant-recessive relationship between A and B) The immune system exhibits tolerance to its own red blood cell antigens People who are type A, for example, not produce anti-A antibodies Surprisingly, however, they make antibodies against the B antigen and, conversely, people with blood type B make antibodies against the A antigen (fig. 13.5) This is believed to result from the fact that antibodies made in response to some common bacteria cross-react with the A or B antigens People who are type A, therefore, acquire antibodies that can react with B antigens by exposure to these bacteria, but they not develop antibodies that can react with A antigens because tolerance mechanisms prevent this People who are type AB develop tolerance to both of these antigens, and thus not produce either anti-A or anti-B antibodies Those who are type O, by contrast, not develop tolerance to either antigen; therefore, they have both anti-A and anti-B antibodies in their plasma (table 13.3) Transfusion Reactions Before transfusions are performed, a major crossmatch is made by mixing serum from the recipient with blood cells from the donor If the types not match—if the donor is type A, for example, and the recipient is type B—the recipient’s antibodies attach to the donor’s red blood cells and form bridges that cause the cells to clump together, or agglutinate (figs 13.5 and 13.6) Because of this agglutination reaction, the A and B antigens are sometimes called agglutinogens, and the antibodies against them are called agglutinins Transfusion errors that result in such agglutination can lead to blockage of small blood vessels and cause hemolysis (rupture of red blood cells), which may damage the kidneys and other organs In emergencies, type O blood has been given to people who are type A, B, AB, or O Because type O red blood cells lack A and B antigens, the recipient’s antibodies cannot cause agglutination of the donor red blood cells Type O is, therefore, a universal donor—but only as long as the volume of plasma Blood, Heart, and Circulation Anti-B Type A 413 Anti-A Type B Type A Antigens on red blood cells Type B Antibodies in plasma Type AB Agglutination reaction Figure 13.6 Figure 13.5 Agglutination reaction People with type A blood have type A antigens on their red blood cells and antibodies in their plasma against the type B antigen People with type B blood have type B antigens on their red blood cells and antibodies in their plasma against the type A antigen Therefore, if red blood cells from one blood type are mixed with antibodies from the plasma of the other blood type, an agglutination reaction occurs In this reaction, red blood cells stick together because of antigen-antibody binding Table 13.3 | The ABO System of Red Blood Cell Antigens Genotype Antigen on RBCs Antibody in Plasma I AI A; I Ai A Anti-B I BI B; I Bi B Anti-A ii O Anti-A and anti-B I AI B AB Neither anti-A nor anti-B donated is small, since plasma from a type O person would agglutinate type A, type B, and type AB red blood cells Likewise, type AB people are universal recipients because they lack anti-A and anti-B antibodies, and thus cannot agglutinate Blood typing Agglutination (clumping) of red blood cells occurs when cells with A-type antigens are mixed with anti-A antibodies and when cells with B-type antigens are mixed with anti-B antibodies No agglutination would occur with type O blood (not shown) donor red blood cells (Donor plasma could agglutinate recipient red blood cells if the transfusion volume were too large.) Because of the dangers involved, use of the universal donor and recipient concept is strongly discouraged in practice Rh Factor Another group of antigens found on the red blood cells of most people is the Rh factor (named for the rhesus monkey, in which these antigens were first discovered) There are a number of different antigens in this group, but one stands out because of its medical significance This Rh antigen is termed D, and is often indicated as Rho(D) If this Rh antigen is present on a person’s red blood cells, the person is Rh positive; if it is absent, the person is Rh negative The Rh-positive condition is by far the more common (with a frequency of 85% in the Caucasian population, for example) The Rh factor is of particular significance when Rhnegative mothers give birth to Rh-positive babies The fetal and maternal blood are normally kept separate across the placenta (chapter 20, section 20.6), and so the Rh-negative mother is not usually exposed to the Rh antigen of the fetus during Index Microglia, 166–167, 166f, 167t, 495 Microglial activation, 167 Microgravity, 384, 691 MicroRNA (miRNA), 67 Microsaccades, 306 Microtubules, 52t, 55, 57, 57f Microvilli, 56, 56f, 136, 298, 629–630 Micturition See Urination Midbrain, 207, 208, 208f, 228–230 Middle ear, 283–284, 283–284f Middle-ear ossicles, 284 Mifepristone, 738 MIF (Müllerian inhibition factor), 705–706, 705f Migraines, treatment of, 192 Milieu intérieur (internal environment), Milk-ejection reflex (milk letdown), 748 Millimeters of mercury (mmHg), 476 MI (myocardial infarction), 110, 380, 392, 414, 439 Mineralocorticoids, 337, 339f, 686 Minerals See also specific minerals free radicals and antioxidants, 114, 666, 668–669 recommended dietary allowances for, 664–665t, 666 Minor calyx, 582 miRNA (microRNA), 67 Mirror neurons, 212 MIT (monoiodotyrosine), 342 Mitochondria, 52t, 59–60, 59f Mitochondrial diseases, 114 Mitochondrial DNA, mutations of, 59, 114 Mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (MELAS), 59, 114 Mitosis, 76–78, 77f Mitral (bicuspid) valve, 419 Mitral cells, 278 Mitral stenosis, 421 Mitral valve prolapse, 421 Mixed micelles, 653 Mixed nerves, 166, 236 MLCK (myosin light-chain kinase), 396 MLCP (myosin light-chain phosphatase), 396 M lines, 367, 367f MMPs (matrix metalloproteinases), 132 Modalities, of sensation, 267 Molality, 138–139, 139f Molar, 29 Molarity, 138–139, 139f Molecules formation of, 26 hydrophilic, 28 hydrophobic, 28 nonpolar, 26 organic, 30–33, 31–32f polar, 26–27, 27f Molybdenum, daily dietary intake of, 668 Monoamine oxidase inhibitors (MAOIs), 192 Monoamine oxidase (MAO), 191 Monoamines, 191–194, 191f, 193f Monoblasts, 410 Monoclonal antibodies, 518, 520 Monocytes, 409, 495–496, 502, 510 Monoglycerides, 653 Monoiodotyrosine (MIT), 342 Monomers, 620 Mononuclear phagocyte system, 54, 408, 495 Mononucleosis, 521 Monosaccharides, 33, 34f Monosynaptic stretch reflex, 387–388, 388t Monovision, 297 Monozygotic twins, 736 Montelukast (Singulair), 352, 545 Morphine, 196, 229 Morula, 737 Motile cilia, 55 Motilin, 648 Motility, 620, 631, 645 Motion sickness, 261 Motor circuit, 216, 216f Motor (efferent) neurons alpha, 387, 388 coactivation of, 387 function of, 207, 244 gamma, 387, 388 lower, 385, 385t skeletal muscle control by, 235, 235f, 361–364, 362–363f structure of, 164t, 165 upper, 210, 385, 385t, 387, 390–391, 391t Motor end plates, 190, 361, 362f, 363 Motor fibers, 166 Motor tracts, extrapyramidal, 233, 235, 390 Motor units, 363–364, 363f, 375 Mountain sickness, 572, 573, 610 Mouth (oral cavity), 621 M phase of cell cycle, 76 MRI (magnetic resonance imaging), 212–213, 212–213f, 220 mRNA (messenger RNA), 46, 63, 65–66, 66f, 68, 71f MSH (melanocyte-stimulating hormone), 332–333, 672 MS (multiple sclerosis), 168, 200, 497, 521, 522t Mucopolysaccharides, 132 Mucosa, gastrointestinal, 621 Mucous glands, 15 Mucous neck cells, 625 Müllerian inhibition factor (MIF), 705–706, 705f Müllerian (paramesonephric) ducts, 705 Multiple sclerosis (MS), 168, 200, 497, 521, 522t Multiplier system, countercurrent, 592–595, 593–594f Multipolar neurons, 166, 166f Multipotent cells, 20, 739 Multipotent growth factor-1, 411 Multispecific organic anion transport carriers, 641 Multiunit smooth muscles, 394, 395f Murad, Ferid, 5t Murmurs, heart, 420–421 Muscarine, 185 Muscarinic ACh receptors, 185, 187, 188–189, 256, 257f, 257t Muscles, 359–398 See also Cardiac muscles; Skeletal muscles; Smooth muscles atrophy of, 78, 384 comparison of, 397t fatigue of, 381–382 hypertrophy of, 78, 384 myoglobin in, 380, 468, 564–565, 565f regeneration of, 384 spasms, 363, 387 Muscle spindle apparatus, 386, 386f Muscle stretch reflex, 387–388 Muscular arteries, 432 Muscular dystrophy, 360, 380 Muscularis, gastrointestinal, 622 Muscularis externa, 622 Muscularis mucosae, 621 Muscular system cell concepts related to, 83 functions of, 20t I-21 membrane transport in, 157 metabolism in, 126 Music, cerebral areas related to, 217 Mutualism, 634 Myasthenia gravis, 186, 189 Myelencephalon, 207, 208f, 231 Myelinated axons, 167–168, 168f, 179–180, 179f Myelin sheath, 167–169, 167–169f Myeloblasts, 410 Myeloid tissue, 409 Myenteric plexus, 622 Myoblasts, 11 Myocardial action potential, 426–427, 426f Myocardial cells, 11, 392 Myocardial infarction (MI), 110, 380, 392, 414, 439 Myocardial ischemia, 110, 439, 440f Myocardium, 392, 418, 425 Myoepithelial cells, 15 Myofibers, 11, 11f, 360 Myofibrils, 364–365, 364–365f Myofilaments, 364f, 365 Myogenic activity, of smooth muscle, 394 Myogenic control mechanisms, 467–468, 473–474 Myoglobin, 380, 468, 564–565, 565f Myokines, 350, 383 Myometrium, 723 Myoneural (neuromuscular) junctions, 180, 190 Myopia, 296, 297, 297f Myosin, 42, 57, 365, 368, 369f Myosin ATPase, 368 Myosin light-chain kinase (MLCK), 396 Myosin light-chain phosphatase (MLCP), 396 Myostatin, 384 Myxedema, 343, 458 N Na1/Ca21 exchanger (NCX), 428 NAD (nicotinamide adenine dinucleotide), 100–101, 101f, 112 NADP (nicotinamide adenine dinucleotide phosphate), 101 Na1 equilibrium potential, 151 Nafarelin, 710 Naloxone, 196–197 Narcolepsy, 232 National Institutes of Health, 672 National Library of Medicine, Natriuresis, 462 Natriuretic hormone See Atrial natriuretic peptide (ANP) Natural killer (NK) cells, 520–521 Nature (journal), Nature Medicine (journal), NCX (Na1/Ca21 exchanger), 428 Near point of vision, 295 Nearsightedness See Myopia Nebulin, 384 Necrosis, 75, 439 Negative chronotropic effects, 452 Negative energy balance, 664 Negative feedback inhibition, 9, 10f, 335 Negative feedback loops, 6–8, 6–10f, 9, 175 Negative nitrogen balance, 122 Neonates first breath of, 540 foramen ovale in, 422 genetic screening of, 746 hemolytic disease of, 414 I-22 Index Neonates—Cont immunity in, 518 jaundice in, 564, 640 sudden infant death syndrome, 558 thermogenesis in, 120–121 vascular resistance in, 551 Neoplasms See Tumors Neostigmine, 186, 187t, 189 Neovascularization, 305 Nephrogenic diabetes insipidus, 598 Nephrolithiasis (kidney stones), 584 Nephron loop See Loop of Henle Nephrons cortical, 586 juxtamedullary, 586 tubules of, 585, 586–587 Nephrotic syndrome, 613 Nephrotoxicity, 600 Nernst equation, 151–152 Nerve cells See Neurons Nerve energies, law of specific, 268–269 Nerve gas, 187t, 189 Nerve growth factor (NGF), 170, 350 Nerve impulses See Action potentials Nerves See also specific names and types classification of, 166 explanation of, 164t, 166 Nervous system, 162–201 See also Autonomic nervous system (ANS); Central nervous system (CNS); Nerves; Neurons; Peripheral nervous system (PNS) cell concepts related to, 83 functions of, 20t homeostatis regulation by, 8–9 membrane transport in, 157 metabolism in, 126 neurilemma and myelin sheath, 167–169, 167–169f neuroglial (glial) cells, 12, 163, 166–167, 166f, 167t overview, 163 regulation by, 8–9 terminology, 164t Nervous tissue, 12, 12f Net diffusion, 134 Net filtration pressure, 457, 588 Net movement, 134 NETs (neutrophil extracellular traps), 415, 502 Neural crest, 207 Neural stem cells, 64, 209, 224 Neural tube, 207 Neurilemma, 167 Neuroendocrine reflexes, 333 Neuroepithelial cells, 274 Neurofibrillary tangles, 221 Neurogenesis, 171, 209, 224 Neurogenic atrophy, 384 Neurogenic mechanism, of breathing and exercise, 570 Neurogenic shock, 486 Neuroglial (glial) cells, 12, 163, 166–167, 166f, 167t Neurohormones, 318 Neurohypophysis, 227, 331 Neurolemmocytes See Schwann cells Neuromuscular (myoneural) junctions, 180, 190 Neuron-glia crosstalk, 171 Neurons See also Axons; specific types astrocytes, 166, 166f, 167t, 170–171, 170f in autonomic nervous system, 244–245, 244f bipolar, 165–166, 166f cable properties of, 177–178, 178f classification of, 165–166, 166f complex, 308 dendrites, 12, 163–164, 163–164f functions of, 12, 163 interneurons, 164t, 165, 207, 385 mirror, 212 multipolar, 166, 166f neurilemma and myelin sheath, 167–169, 167–169f neurotrophins and, 170 olfactory, 209 in peripheral nervous system, 244 pseudounipolar, 165, 166f pyramidal, 223, 223f regeneration of, 169, 169f simple, 308, 308f structure of, 163–164, 163–164f synapses, 154, 180–183, 181–182f, 184f Neuropeptides, 196 Neuropeptide Y, 197, 672 Neurotransmitters See also specific types actions of, 183, 184f amino acids as, 194–195, 196t in autonomic nervous system, 251–258 chemical proven or suspected to be, 196t endocannabinoids as, 196t, 197–198 excitatory, 194–195 explanation of, 154, 181 gases as, 196t, 198 inhibitory, 195 monoamines as, 191–194, 191f, 193f polypeptides as, 196–197, 196t release of, 182–183, 182f retrograde, 197 Neurotrophins, 170, 350 Neurovascular coupling, 474 Neutral fats, 36 Neutral solutions, 29 Neutrons, 25 Neutrophil extracellular traps (NETs), 415, 502 Neutrophils, 54, 408, 495 Newborns See Neonates New England Journal of Medicine, NGF (nerve growth factor), 170, 350 Niacin See Vitamin B3 Nicotinamide adenine dinucleotide (NAD), 100–101, 101f, 112 Nicotinamide adenine dinucleotide phosphate (NADP), 101 Nicotine, 185, 193, 229, 256t See also Smoking Nicotinic ACh receptors, 185, 186f, 256, 257f, 257t Nidation (implantation), 738 Niedergerde, R., 5t Nigrostriatal dopamine system, 192, 193, 216, 229 Nissl bodies, 163 Nitric acid, 29t Nitric oxide (NO), 196t, 198, 258, 350, 414, 466 altitude and, 572 blood clotting and, 414, 415f blood flow and, 350, 466, 470, 474 calcium and, 258 in central nervous system, 198 erection and, 198, 258, 719–720, 720f as hormone, 466 in local inflammation, 502 in memory, 224 as neurotransmitter, 196t, 198, 258 as paracrine regulator, 258, 350, 466 in peripheral nervous system, 198 septic shock and, 510 vasodilator and, 466 Nitric oxide radicals, 668 Nitric oxide synthase, 466, 486 Nitric oxide synthetase, 258 Nitrogen, atomic structure of, 25t Nitrogen balance, 122 Nitrogen narcosis, 552 Nitrogenous bases, 44, 45, 45f, 63 Nitroglycerin, 110, 466 Nitrous oxide, 198 NK (natural killer) cells, 520–521 NMDA (N-Methyl-D-aspartate) receptors, 194–195, 199, 222 N-Methyl-D-aspartate (NMDA) receptors, 194–195, 199, 222 Nobel Prize in Physiology or Medicine apoptosis, 75 dendritic cells, 510 G-proteins, 155 Helicobacter pylori, 628 history of, 5–6, 5t knockout mice, 75 nerve growth factor, 170 olfactory sensory neurons, 276 recognition of medicine and physiology relationship, RNA interference, 67 secretory vesicles docking with target membranes, 61 stem cell research, 19, 739 synaptic vesicles, 183 telomeres and telomerase, 78 toll-like receptors, 495 Nociceptors (pain receptors), 267, 268t, 270 Nodes of Ranvier, 168, 179–180 NOD-like receptors, 495 Nogo receptors, 169 Nonalcoholic fatty liver disease, 637 Non-carrier-mediated transport, 133 Nondeclarative (implicit) memory, 220, 221t Nonessential amino acids, 122, 122t Nongenomic action, of steroids, 324 Nongranular leukocytes, 408, 409f, 410t Non-Hodgkin’s lymphoma, 520 Noninvasive fetal sex determination, 742 NO (nitric oxide), 196t, 198, 258, 350, 414, 466 Nonkeratinized epithelium, 13t, 14, 14f Nonpolar covalent bonds, 26 Nonpolar hormones, 319–320 Nonpolar molecules, 26 Non-REM sleep, 214–215, 220 Non-self antigens, 517 Nonshivering thermogenesis, 260, 675 Nonspecific immunity See Innate immunity Nonsteroidal anti-inflammatory drugs (NSAIDs), 352 Nonvolatile acids, 568 Noradrenaline See Norepinephrine Norepinephrine cardiac contraction strength and, 454 cardiac rate and, 452 in drug abuse, 194, 251 as hormone, 191, 318 as neurotransmitter, 194, 251–254, 318 receptors for, 253–255, 256t secretion of, 247, 337 as vasoconstrictor, 433, 466 Normal saline rhythm, 426 Normal saline solutions, 140, 141 Normoblasts, 411 Nose See Smell Nosocomial infections, 635 NSAIDs (nonsteroidal anti-inflammatory drugs), 352 N-3 fatty acids in, 439, 666 Index Nuclear bag fibers, 386 Nuclear chain fibers, 386 Nuclear envelope, 52t, 62 Nuclear hormone receptors, 323–325, 324f Nuclear pore complexes, 63 Nuclear pores, 62f, 63 Nuclei, 163, 164t, 209 Nucleic acids, 41, 44–47, 45f See also DNA (deoxyribonucleic acid); RNA (ribonucleic acid) Nucleoli, 52, 63 Nucleolus, 52t, 66 Nucleosomes, 64 Nucleotides, 44–45, 45–46f, 46, 63 Nucleus arcuate, 672 of atoms, 25 caudate, 215, 391 of cells, 52, 62–63, 62f lentiform, 215 red, 229, 391 retrotrapezoid, 554 subthalamic, 216, 391 ventrolateral preoptic, 231 Nucleus accumbens, 193, 228 Null hypotheses, Nutritional requirements, 662–669 Nystagmus, vestibular, 282 O OATs (organic anion transporters), 599, 600, 641 Obesity, 120, 671–672, 682–683 Obligatory water loss, 590, 597 Obscurin, 384 Obstructive disorders, 544 Obstructive sleep apnea, 558 Occipital lobe, 210, 211t, 212 OCTs (organic cation transporters), 599 Oculomotor nerves, 237t, 248, 250 Oddi, sphincter of, 643 Off-center fields, 307 Olfaction See Smell Olfactory bulb, 277, 277f, 278 Olfactory nerves, 237t Olfactory neurons, 209 Olfactory receptors, 209, 274, 275, 276–278, 278f Oligodendrocytes, 166, 166f, 167t, 168–169, 168f Oligosaccharides, 650, 651f Oligospermia, 722 Oliguria, 510 Olive, superior, 288 Omega-3 fatty acids, 666 Omeprazole (Prilosec), 627 On-center fields, 307 Oncogenes, 67, 75 Oncology See Cancer Oncotic pressure, 457 Ondine’s curse, 554 One atmosphere, pressure of, 547 One-molal solutions, 139, 139f One-molar solutions, 138, 139f Oocytes, 724, 725 Oogenesis, 725, 727f Oogonia, 704 Open-angle glaucoma, 293 Ophthalmia, sympathetic, 522, 522t Opioids, 196–197, 196t, 229 Opsin, 299 Opsonization, 496, 502, 506 Optical isomers, 32, 32f Optic chiasma, 306 Optic disc, 294 Optic nerves, 237t Optic radiation, 308 Optic tectum See Superior colliculi Oral cavity, 621 Oral contraceptives, 322, 733 Oral glucose tolerance test, 678–679 Oral phase, of swallowing, 623–624 Oral rehydration therapy (ORT), 148 Orbital, of electrons, 25–26 Orbitofrontal area, 224, 275 Orexin, 232 Organelles, 52, 57 Organic acids, 31, 32f Organic anion transporters (OATs), 599, 600, 641 Organic cation transporters (OCTs), 599 Organic molecules, 30–33, 31–32f Organ of Corti, 286–288, 287f Organophosphate pesticides, 189 Organs See also specific organs and organ systems explanation of, 11, 18 stem cells and, 19–20 Organ-specific phagocytes, 495 Organ systems, 20, 20t See also specific systems Orgasm, 258, 712 Orgasmic platform, 712 Origin, of skeletal muscle, 360 Orphan receptors, 324 Orthostatic hypotension, 478 ORT (oral rehydration therapy), 148 Oscilloscope, 172–173, 172f Osmolality ADH secretion and, 141f, 142, 460, 460f, 596–598, 597f of blood, 141–142, 141f, 460, 460f, 596–598, 597f of kidneys, 595, 596, 596f measurement of, 139–140 Osmoreceptors, 141, 333, 460 Osmosis, 34, 135, 136–137, 137f, 590 Osmotically active solutes, 136 Osmotic diuretics, 611t, 612 Osmotic pressure, 137–138, 138f, 457 Ossicles, middle-ear, 284 Osteitis fibrosa cystica, 695 Osteoblasts, 16, 690 Osteocalcin, 693 Osteoclasts, 690, 691f Osteocytes, 16–17 Osteomalacia, 695 Osteons, 17 Osteoporosis, 693 Osteoprotegerin, 690, 692 Otic ganglion, 250 Otitis media, 283 Otolithic membrane, 280 Otolith organs, 279, 280, 281f Otosclerosis, 283 Outer ear, 283, 283f Outer hair cells, 286–287 Outer segment, of rods and cones, 298 Ova See Ovum Oval window, 284 Ovarian cycle, 724–725 Ovarian follicles, 349, 705, 725, 725f, 728f Ovaries cyclic changes in, 728–731 endocrine functions of, 317f, 318t, 349 I-23 exocrine functions of, 16 formation of, 704–705, 704f pituitary gland and, 727 sex steroid secretion by, 40, 709 Overactive bladder, 258, 584 Overshoot, of membrane potentials, 175 Ovulation, 725–727, 726f, 729–730 Ovum development of, 725 fertilization of, 702, 704, 734–737, 735–736f follicles of, 349 Oxaloacetic acid, 122f, 123 Oxidases, 58 Oxidation, 99–101, 101f b-Oxidation, 120, 121f Oxidation-reduction reactions, 99–101, 101f Oxidative deamination, 123, 123f Oxidative phosphorylation, 59, 112, 115, 115f, 116 Oxidative stress, 114, 668–669 Oxidized hemoglobin, 559 Oxidizing agent, 100 Oxygen in aerobic cell respiration, 107, 111, 111f atomic structure of, 25t in blood, 467–468, 548, 550, 570–571 cardiac requirements for, 468–469 diffusion of, 135, 135f, 550 dissolved, 548 in electron-transport system, 114–115 in gas exchange, 547–552 hemoglobin affinity for, 572 hyperbaric therapy, 552 maximal uptake of, 379, 382–383 myoglobin affinity for, 565 normal range in blood, 6t partial pressure of, 547, 548, 549f, 550, 551f reactive species of, 59, 115, 222, 668–669, 668f utilization of, 533 Oxygen-carrying capacity, 560 Oxygen debt, 125, 379 Oxygen electrode, 548 Oxygen toxicity, 552 Oxygen transport, 559–565 Oxyhemoglobin, 550, 559, 561–562 Oxyhemoglobin dissociation curve, 561–562, 561–562f, 563t Oxytocin actions of, 333 lactation and, 748 production of, 227 secretion of, 333 transport of, 227 uterine contraction and, 8, 333, 744 P Pacemaker cells, 392 Pacemaker potentials, 425–426, 425f, 451, 451f Pacemakers, 441 artificial, 441 cardiac, 392, 425–426, 440, 451f, 452 ectopic, 426, 440 intestinal, 631 in smooth muscles, 394 urinary system, 584 Pacinian corpuscles, 269, 270, 270t Paget’s disease, 695 PAH (para-aminohippuric acid), 602f, 603 I-24 Index Pain phantom, 272 receptors, 267, 268t, 270 referred, 272, 439 Palindromes, 703 PAMPs (pathogen-associated molecular patterns), 495 Pancreas as accessory digestive organ, 621, 622f acini of, 643 endocrine, 317, 317f, 318t, 345–346, 643, 643f enzyme activation in, 94 exocrine, 15, 317, 345, 643, 643f location of, 636 parasympathetic activity in, 622 trophic effects on, 650 Pancreatic amylase, 643, 645, 649, 650, 651f, 651t Pancreatic islets cell types of, 345–346, 346f, 677 in diabetes mellitus, 681–685 endocrine function of, 9, 317, 317f, 318t, 345–346, 643 metabolic regulation by, 677–680 Pancreatic juice, 93, 642f, 643–644, 644f, 644t, 649 Pancreatic lipase, 643, 649, 652 Pancreatic trypsin inhibitor, 644 Pancreatitis, 645 Paneth cells, 629 Panic disorder, 192 Pantothenic acid, 666, 667t Papez circuit, 219 Papillary muscles, 419 Pap smears, 14, 15 Para-aminohippuric acid (PAH), 602f, 603 Paracellular transport, 147–148 Paracrine regulation adenosine and ATP in, 198 in atherosclerosis, 350, 437 of blood flow, 466–467 explanation of, 350 of gastrointestinal tract, 622, 625, 647 in testes, 715 Paracrine signaling, 154 Paradoxical cold, 269 Parafollicular cells, 341, 342 Paralysis flaccid, 183, 390 spastic, 183, 390, 391t Paralysis agitans See Parkinson’s disease Paralytic shellfish poisoning, 186 Paramesonephric (Müllerian) ducts, 705 Paraplegia, 391t Parasternal intercostals, 541 Parasympathetic nervous system in blood flow regulation, 466, 467t in cardiac regulation, 452, 452t, 454 cranial nerves in, 248–250, 249f, 249t functions of, 251 in gastrointestinal regulation, 622 glucagon secretion and, 679 insulin secretion and, 679 neurotransmission in, 190, 251–252, 252–253f postganglionic fibers of, 248, 249t preganglionic fibers of, 247–248 sympathetic nervous system and, 248, 258–260, 259t Parathyroid glands, 318t, 344, 345f Parathyroid hormone (PTH) action of, 319t, 344, 345f, 692 negative feedback control of, 695, 695f secretion of, 344, 345f, 692 vitamin D and, 321 Paraventricular nuclei, 227, 333 Paravertebral ganglia, 246, 246f Parent cells, 72, 73, 79, 80f Parietal cells, 625, 645, 646 Parietal lobe, 210, 211t Parietal pleura, 536, 537–538 Parkinson’s disease, 171, 192, 193, 200, 216, 229, 391 etiology of, 193, 216, 229, 391 excitotoxicity in, 200 extrapyramidal symptoms in, 233 oxidative stress and, 669 stem cell therapy for, 739–740 symptoms of, 193 treatment of, 171, 192, 193, 216 tremor of, 230, 391 Pars distalis See Anterior pituitary gland Pars intermedia, 331, 332 Pars nervosa See Posterior pituitary gland Pars tuberalis, 331, 331f, 332 Partial pressure of gases altitude and, 547, 548t, 571–572, 573t in blood, 548, 550 calculation of, 547 exercise and, 570 hemoglobin and, 560, 561f, 561t significance of, 550 ventilation and, 555–557 Parturition, 745–746 Passive immunity, 518, 519t Passive transport, 133, 133f, 144, 590–591 Pasteur, Louis, 515 Patellar tendon reflex See Knee-jerk reflex Patent ductus arteriosus, 422 Patent foramen ovale, 422 Pathogen-associated molecular patterns (PAMPs), 495 Pathogen recognition receptors (PRRs), 495, 512, 517 Pathogens, 494 Pathophysiology, Pavlov, Ivan, 5t Paxil, 192 PCBs (polychlorinated biphenyls), 641 PCOS (polycystic ovarian syndrome), 732 PCP (angel dust), 199 PDGF (platelet-derived growth factor), 329, 351 “Pear shape,” 671 Pectoralis minor, 541 Pedicels, 587f Peer-reviewed journals, 3–4 Pelvis, renal, 582 Penfield, Wilder, 221 Penicillin, 600 Penile urethra, 706 Penis, 198, 258, 706, 719–721, 720–721f Pentose, 44 Pepcid, 627 Pepsin, 92–93, 626–628, 627f, 651–652 Pepsinogen, 625, 645, 646 Peptic ulcers, 352, 628 Peptide bonds, 41–42, 42f Peptides, 41, 196 Percent oxyhemoglobin saturation, 560, 561, 561t Perception, 267 Perceptive deafness, 289 Perforins, 507 Perfusion ratio, 550–552, 552f Periarteritis, 523 Pericentriolar material, 76 Periglomerular cells, 278 Perikaryon See Cell bodies Perilymph, 279, 285, 288 Perimetrium, 723 Perimysium, 360 Peripheral chemoreceptors, 554, 556–557 Peripheral nervous system (PNS) acetylcholine in, 190 components of, 236 explanation of, 163, 164t myelin sheath in, 167–168, 167–168f neuroglial (glial) cells in, 166, 167t neurons of, 244 relationship with CNS, 165, 165f Peripheral proteins, 53 Peripheral resistance, total, 452, 465, 476 Peripheral tolerance, 518 Peristalsis, 12, 584, 620, 624, 624f Peristaltic waves, 393 Peritoneal dialysis, 134 Peritonitis, 633 Peritubular capillaries, 586 Permeability, selective, 132, 136 Permissive effects, of hormones, 321 Pernicious anemia, 408, 521, 522t, 625 Peroxisome proliferator activated receptor (PPAR), 670 Peroxisomes, 52t, 58 Pesticides, 189 PET (positron-emission tomography), 192, 212, 213t Peyer’s patches, 499 p53 gene, 75–76 PGH (placental growth hormone), 743 pH See also Acid-base balance altitude and, 572, 610 exercise and, 570–571, 570f of gastric juice, 626, 647 optimum, 92–93, 93f, 93t oxygen transport and, 562, 562t plasma, 567, 568 scale, 29–30, 30t ventilation and, 555–557, 556–557f Phagocytes, 495–496 Phagocytosis antibody-stimulated, 506–507 in immune complex diseases, 522–523 in innate immunity, 494t, 495–497, 496f in liver, 637, 640 in local inflammation, 500, 502 Phantom limb phenomenon, 272 Pharmaceutical drugs See Drugs Pharmacological concentrations, of hormones, 322 Pharyngeal phase, of swallowing, 623–624 Pharynx, 536, 621 Phases of clinical trials, Phasic receptors, 268, 268f Phenacetin, 613 Phentolamine, 256t Phenylalanine, 96, 96f, 122t Phenylephrine, 255, 256t Phenylketonuria (PKU), 96, 97t Pheochromocytoma, 339 Pheromones, 732–733 Phosphatases, 91 Phosphate balance, regulation of, 604, 690–695, 690t functional groups of, 32f regulation of, 690–695, 690t Phosphatidylcholine See Lecithin Phosphatidylglycerol, 540 Phosphatidylserine, 54, 417, 496 Phosphocreatine, 379–380, 380f Index Phosphodiesterase, 301, 328 Phospholipase, 652 Phospholipase A, 652 Phospholipase C, 328 Phospholipase C–Ca21 second messenger system, 328–329, 329f, 330t Phospholipids in bile, 638 in blood clotting, 415, 416f characteristics of, 38–39, 39f digestion of, 652 in plasma membrane, 53, 53f in surfactant, 540 Phosphoric acid, 29t Phosphorus, recommended dietary allowance for, 665t, 668 Phosphorylation See also Oxidative phosphorylation direct, 115 enzyme activation and, 94 in glycolysis, 108 Photopsins, 301 Photoreceptors See also Cones; Rods adequate stimulus for, 267, 268t, 298–299 dark current in, 301, 301–302f distribution of, 304 electrical activity in, 300–301, 301f, 302f Photosynthesis, 98, 98f Phototherapy, 348, 564 Phrenic motor nuclei, 554 Phrenic nerves, 554 Physical activity See Exercise Physiological concentrations, of hormones, 322 Physiological dead space, 544t Physiological jaundice of the newborn, 564, 640 Physiological Reviews (journal), Physiology comparative, explanation of, history of, 4–6, 5t Physiology (journal), Physostigmine, 189 Pia, 208 PIH (prolactin-inhibiting hormone), 335 Pilocarpine, 256t Pineal gland, 226, 228, 318t, 346–348, 348f, 712 Pinna, 283 Pinocytosis, 54–55 Pioglitazone (Actos), 684 Piriform cortex, 278 Pitch, 283, 285–286, 286f, 288–289 Pitch discrimination, 288 Pitocin, 333 See also Oxytocin Pituicytes, 331 Pituitary-adrenal axis, 337 Pituitary dwarfism, 332 Pituitary gland, 331–337 See also Anterior pituitary gland; Posterior pituitary gland characteristics of, 318t feedback control of, 335–336, 336f higher brain function and secretion, 336–337 hormones of, 331–333, 332t hypothalamic control of, 333–335, 333–335f, 335t regulation of, 227 structure of, 331, 331f Pituitary-gonad axis, 336, 336f Pituitary-ovarian axis, 727 Pituitary-thyroid axis, 336, 336f PKD (polycystic kidney disease), 586 PKU (phenylketonuria), 96, 97t Placenta, 349, 413, 484, 740–744, 744t Placental growth hormone (PGH), 743 Placental lactogen, 743 Place theory of pitch, 289 Planaria, gastrointestinal tract of, 620 Plaques in Alzheimer’s disease, 221–222 in atherosclerosis, 436–437 Plasma clotting factors, 415–417, 416f, 416t constituents of, 406–407, 406f, 407t explanation of, 20 in extracellular compartment, 131 fluid exchange with tissue, 457, 458f osmolality of, 141–142, 141f, 460, 460f, 596–598, 597f pH of, 567, 568 proteins in, 137, 407, 503, 587–588, 641 regulation of, 21 volume, 407 Plasma (cell) membranes cilia and flagella, 52t, 55–56, 56f diffusion through, 135–136, 135f endocytosis in, 54–55, 55f, 149, 149f exocytosis in, 55, 148, 149, 149f, 182 microvilli, 56, 56f, 136 osmosis and, 34, 135, 136–137, 137f phagocytosis in, 54, 54f selective permeability of, 132, 136 structure and function of, 52–54, 52t transport across, 132–133, 133f Plasma cells, 503, 503f, 508f, 516 Plasma clearance, renal, 598–604, 600f, 601–602t, 602–603f Plasma proteins, 407, 641 Plasma threshold, renal, 604 Plasma volume, 407 Plasmin, 417 Plasminogen, 417 Plasticity, synaptic, 199–200 Plateau phase, 426–427, 712 Platelet aggregation inhibitors, 414 Platelet-derived growth factor (PDGF), 329, 351 Platelet inhibitors, 414 Platelet plugs, 414 Platelet release reaction, 414 Platelets, 409, 409f, 414, 415f, 522 Plavix (clopidogrel), 414 Pleural membranes, 536 Pluripotent cells, 19, 64, 738 PMNs (polymorphonuclear leukocytes), 409 Pneumotaxic respiratory center, 230, 554 Pneumothorax, 539, 539f, 544t PNS See Peripheral nervous system Podocytes, 587 Point mutation, 75 Poiseuille’s law, 464 Poison ivy, 526 Poison oak, 526 Poison sumac, 526 Polar body, 725, 726f, 727f Polar hormones, 319–320 Polarity, in transport, 149 Polar molecules, 26–27, 27f Polio, 55, 517 Pollen, 524 Pollution, 544 Polychlorinated biphenyls (PCBs), 641 Polycystic kidney disease (PKD), 586 Polycystic ovarian syndrome (PCOS), 732 Polycystin-1 protein, 586 I-25 Polycystin-2 protein, 586 Polycythemia, 409, 560 Polydipsia, 598 Polymerases, 65, 73, 78 Polymers, 620 Polymorphonuclear leukocytes (PMNs), 409 Polypeptide hormones, 319, 319t Polypeptides, 42, 69–70, 196–197, 196t Polypeptide YY (PYY), 673 Polyribosomes, 68, 68f Polysaccharides, 34 Polysome, 68, 68f Polyspecific carriers, 600 Polyspermy, 736 Polyuria, 598 POMC (pro-opiomelanocortin), 333 Pompe disease, 58 Pons, 230, 554 Porphyria, 641 Porphyrin, 641 Portal system hepatic, 636 in pituitary gland, 334–335 Portal vein, hepatic, 636, 637f Positive chronotropic effects, 452 Positive energy balance, 664 Positive feedback effect, 336 Positive feedback loops, 8, 174, 593 Positive inotropic effect, 454 Positive nitrogen balance, 122 Positron-emission tomography (PET), 192, 212, 213t Postabsorptive (fasting) state, 675 Postcentral gyrus, 210–211, 271 Posterior chamber, of eye, 293 Posterior pituitary gland hormones of, 333, 334f hypothalamic control of, 333, 333f structure of, 331, 331f Posterior spinocerebellar tract, 233t Postganglionic neurons, 244, 244f, 246, 247, 248 Postsynaptic inhibition, 200–201, 200f Postsynaptic neurons, 181 Posttranslational modifications, 63 Post-traumatic stress disorder (PTSD), 224 Postural hypotension, 478 Postural muscles, 380 Potassium abnormal levels of, 152, 606, 612 active transport of, 145–146, 145f blood flow and, 474 dietary requirement for, 668 diuretics and, 606 equilibrium potential, 150–151, 150f hydrogen ions and, 608, 608f in hydrogen-potassium ATPase pumps, 626 intracellular concentration of, 149–150 reabsorption of, 604–605, 605f renal regulation of, 604–606 secretion of, 605–606, 605f sodium ions and, 608, 608f Potassium channels, 135–136, 152, 172–176, 174–176f Potassium hydroxide, 29t Potassium-sparing diuretics, 611t, 612 Potential difference, 150 Potentials, electric See Action potentials; Equilibrium potentials; Membrane potentials Potentiation, long-term, 199–200, 222, 223f, 224 Power stroke, 368–369, 369f PPAR (peroxisome proliferator activated receptor), 670 I-26 Index PPIs (proton pump inhibitors), 627 Pre-Bötzinger complex, 554 Precapillary sphincters, 433 Precentral gyrus, 210–211, 233 Precursor messenger RNA (pre-mRNA), 65, 66, 66f Prednisolone, 340, 514 Prednisone, 340, 514 Preeclampsia, 333, 484 Prefrontal cortex, 221, 224–225 Preganglionic neurons, 244, 244f, 247 Pregnancy breast changes during, 745 induction of labor in, 333 preeclampsia in, 333, 484 Rh factor and, 413–414 termination of, 738 tests for, 498, 740 Pregnancy tests, 740 Prehormones, 320–321, 320t Preload, 452 Premature infants, 540 Preproinsulin, 70, 320 Presbycusis, 289 Presbyopia, 295–296 Prescription drugs See Drugs Presenilin, 222 Pressure, receptors for, 270 Pressure difference, 464, 464f Presynaptic axon terminals, 254 Presynaptic inhibition, 201 Presynaptic neurons, 181 Prevacid (lansoprazole), 627 Prevertebral (collateral) ganglia, 247, 248f Prilosec (omeprazole), 627 Primary active transport, 144–145 Primary adrenal insufficiency, 338 Primary cilium, 55, 586 Primary (essential) hypertension, 482–483 Primary gustatory cortex, 275 Primary hyperaldosteronism, 606 Primary immune response, 515, 515f Primary lymphoid organs, 499 Primary lysosomes, 58 Primary motor cortex, 233 Primary olfactory cortex, 278 Primary processes, of podocytes, 587 Primary sensory endings, 386 Primary spermatocytes, 716 Primary structure, of proteins, 42, 42f Primary tissues, 10–18 connective, 14, 16–18, 16–18f epithelial, 12–16, 13–16f, 13t muscle See Muscles nervous, 12, 12f overview, 10–11 Priming effects, of hormones, 322 Principal piece, of spermatozoa, 718 P-R interval, 441 PRL (prolactin), 332, 332t, 746 Probenecid, 600 Probucol, 438 Procainamide, 426 Procaine, 175 Procedural memory, 221t Proceedings of the National Academy of Sciences (journal), Products, from chemical reactions, 91 Progesterone in menstrual cycle, 728–731, 729–730f in ovulation, 727 in placenta, 744, 744f secretion of, 349 Programmed cell death See Apoptosis Prohormones, 320 Proinsulin, 70, 72f, 320 Prolactin-inhibiting hormone (PIH), 335 Prolactin (PRL), 332, 332t, 746 Prolactin-releasing hormone, 748 Proliferative phase, of endometrium, 731 Proline, 122t Promoters of genetic transcription, 65 Pro-opiomelanocortin (POMC), 333 Prophase of cell cycle, 76, 77f, 79, 80f, 81t Propranolol, 255, 426 Proprioceptors, 230, 268 Prosencephalon See Forebrain Prostacyclin, 351, 414 Prostaglandin E1, 40f Prostaglandin E2, 40f, 351, 352, 502 Prostaglandin F1, 40f Prostaglandin F2, 40f, 352 Prostaglandin I2 (prostacyclin), 352, 414, 466 Prostaglandins actions of, 40, 350t, 351–352 in allergy/hypersensitivity, 524, 545 blood clotting and, 352, 414, 415f blood flow and, 466, 467t, 469 gastrointestinal mucosa and, 628 inhibition of, 352 in local inflammation, 502 structure of, 40, 40f, 351 synthesis of, 351–352, 351f uterine contractions and, 744, 745f Prostate, 16, 706, 719 Protamines, 716 Protanopia, 303 Protease enzymes, 71–72 Protease inhibitors, 509 Proteasome, 72 Proteinase, in emphysema, 545, 546 Protein kinase, 94, 192, 327 Protein malnutrition, 689 Proteins See also Amino acids antibodies as, 44, 498 caloric value of, 650 composition in body, 43–44, 43t conjugated, 44 degradation of, 70–72 denaturation of, 43 digestion and absorption of, 651–652, 652f enzymes as, 44, 71–72, 89 formation of, 41–42 functions of, 44 as hormones, 319 in human genome, 63 integral, 53 metabolism of, 119 normal range in blood, 6t peripheral, 53 in plasma membrane, 53–54 recommended dietary allowance for, 662, 664t regulatory, 71–72 secretion of, 70, 71f structure of, 42–43, 42–43f synthesis of, 68–72 turnover of, 94 uncoupling, 121, 675, 686, 687 in urine, 588 Proteinuria, 484, 588, 613 Proteoglycans, 132 Proteomes, 63 Proteomics, 63 Prothrombin, 416 Proton acceptors, 29 Proton donor, acid as, 29 Proton pump inhibitors (PPIs), 627 Proton pumps, 113, 115f Protons, 25 Proto-oncogenes, 75 Proximal convoluted tubules, 586, 590–592, 595t, 603, 603f Prozac, 192 PRRs (pathogen recognition receptors), 495, 512, 517 Pruritus, receptors for, 271 Pseudoephedrine, 255 Pseudogenes, 276 Pseudohermaphroditism, 706, 707 Pseudopods, 54 Pseudounipolar neurons, 165, 166f Psilocybin, 192 Psoriasis, 521, 522t, 667 Pterygopalatine ganglion, 250 PTH (parathyroid hormone), 321, 344, 345f, 692, 692f PTSD (post-traumatic stress disorder), 224 Ptyalin See Salivary amylase Puberty, 348, 710–712, 711f, 711t Pubic hair, 711, 711t PubMed website, Pudendal nerve, 584 Pulmonary arteries, 418, 550, 551–552 Pulmonary capillaries, 533–534, 533–534f, 548 Pulmonary circulation, 418–419, 419f, 419t, 550–552 Pulmonary disorders, 544–546 Pulmonary edema, 551, 572 Pulmonary embolism, 417 Pulmonary fibrosis, 538, 546 Pulmonary function tests, 542–544, 542t, 543–544f Pulmonary hypertension, 573 Pulmonary receptors, and ventilation, 558–559 Pulmonary semilunar valves, 419–420, 420f Pulmonary stretch receptors, 558 Pulmonary trunk, 418 Pulmonary veins, 418 Pulmonary ventilation See Ventilation Pulp, of tooth, 18, 18f Pulsatile secretion, 322, 709 Pulse oximeters, 550, 560 Pulse pressure, 481–482 Pumps calcium, 145, 145f circulatory See Heart hydrogen-potassium ATPase, 626 proton, 113, 115f skeletal muscle, 435 sodium-potassium, 145–146, 145f, 153, 175–176 Pumps, in active transport, 133, 144–145, 145f Punishment system, cerebral areas related to, 219–220 Pupillary reflex, 307 Pupils, 290, 291t, 292, 292f Purinergic receptors, 198 Purines, 44, 45, 196t, 198 Purkinje cells, 195, 230 Purkinje fibers, 425, 426, 427 Pus, 502 Putamen, 215, 391 P waves, 428, 429f Pyelonephritis, 613 Pyloric region, 625 Pyloric sphincter, 625, 645 Index Pyramidal neurons, 223, 223f Pyramidal tract See Corticospinal tract Pyramids in medulla oblongata, 231 renal, 582, 583f Pyridostigmine, 189 Pyridoxine See Vitamin B6 Pyrimidines, 44, 45 Pyrogens, endogenous, 497 Pyrophosphate, 327 Pyruvic acid (pyruvate), 107–108, 109, 118, 122f, 123 PYY (polypeptide YY), 673 Q QRS waves, 428, 429f Quadriplegia, 391t Quantitative measurements, 3, 7–8 Quaternary structure, of proteins, 42f, 43 Quick-acting beta agonists, 545 Quinidine, 426 R Rabeprazole (Aciphex), 627 Radial artery, pulse at, 423–424 Radiation, optic, 308 Radicals free, 114, 666, 668–669 hydroxyl, 668 nitric oxide, 668 superoxide, 114, 668 Ragweed, 524, 525f Rami communicantes, 246, 246–247f Ranibizumab (Lucentis), 435 RANK, 690, 692 RANKL, 690, 692 RANK ligand, 690, 692 Ranvier, nodes of, 168, 179–180 Raphe nuclei, 192 Rapid eye movement (REM) sleep, 214–215, 220, 349 Rapid filling, of ventricles, 423 Rapidly adapting receptors, 558 Rapid stretching, 387 RAS (reticular activating system), 231–232, 231f Rathke’s pouch, 331 RDS (respiratory distress syndrome), 540 Reabsorption, 143, 147, 459, 590–598, 591f Reactions See Chemical reactions Reactive hyperemia, 468 Reactive hypoglycemia, 685, 685f Reactive nitrogen species, 668 Reactive oxygen species, 668, 668f Receptive fields, 272–273, 307 Receptor (generator) potentials, 269, 269f Receptor-mediated endocytosis, 55 Receptors antigens, 497–498, 510–511 death, 75 dimerization of, 324 downregulation of, 322 G-protein-coupled, 186–189, 188f, 188t olfactory, 209, 274, 275, 276–278, 278f phasic, 268, 268f protein, 44, 53–54, 154–155, 182, 323–325, 495 proteins, 44, 55, 154, 183, 253, 317, 321 pulmonary, 558–559 purinergic, 198 sensory See Sensory receptors tonic, 268, 268–269f upregulation of, 322 Reciprocal innervation, 389–390, 389f Recombinant human growth hormone, 690 Recombinant vaccines, 517 Recombination, genetic, 79, 497 Recruitment process, 176, 364, 374 Rectum, 633 Recurrent circuits, 222 Red blood cells See Erythrocytes Red cones, 303, 303f Red fibers, 380 Red-green color blindness, 303 Redness, in inflammation, 502 Red nucleus, 228, 391 Reducing agents, 100 5a-Reductase, 706, 707 Reduction, 99–101, 101f Reduction division, 81 See also Meiosis Referred pain, 272, 439 Reflexes arc, 238–239, 387 Babinski’s, 235, 391t baroreceptor, 477–478f, 477–479 cremasteric, 705 crossed-extensor, 390, 390f defecation, 636 gastroileal, 648 Golgi tendon organs, 389, 389f guarding, 584 Hering-Breuer, 558 ileogastric, 648 intestinal, 648 intestino-intestinal, 648 knee-jerk, 238, 388, 388f milk-ejection, 748 neuroendocrine, 333 pupillary, 307 skeletal muscles, 238–239, 387–390, 388–390f, 388t stretch, 387–388, 388t, 479 voiding, 584 Refraction, 294, 294–295f Refractive index, 294 Refractory errors, 297, 297f Refractory periods, 177, 177f, 428, 428f, 712 Regeneration of axons, 169, 169f of liver, 637 of muscle, 384 of neurons, 169, 169f Regeneration tubes, 169, 169f Regenerative medicine, 739 Regulatory proteins, 71–72 Regulatory T lymphocytes, 508, 518 Rehydration therapy, 148 Relapse, in drug abuse, 229–230 Relative refractory periods, 177, 177f Relaxation isovolumetric, 423 skeletal muscles, 373 smooth muscles, 395 Relaxin, 746 Release channels, calcium, 371 Releasing hormones, 227 REM (rapid eye movement) sleep, 214–215, 220, 349 Renal artery, 585 Renal autoregulation, 589–590 Renal blood vessels, 585–586, 585f I-27 Renal calculi, 584 Renal columns, 582 Renal corpuscle, 586 Renal failure, 613 Renal insufficiency, 613 Renal pelvis, 582 Renal plasma clearance, 598–604, 600f, 601–602t, 602–603f Renal plasma threshold, 604 Renal pyramids, 582, 586f, 587 Renal vein, 586 Renin, 606–607, 608t Renin-angiotensin-aldosterone system, 461–462, 462f, 606 Reperfusion injury, 439 Replication of DNA, 72–74, 73–74f Repolarization, 173, 175, 426, 428, 430 Reproducible data, Reproductive cloning, 738 Reproductive system cell concepts related to, 83 embryonic development, 706–707 endocrine regulation of, 708–712 female See Female reproductive system functions of, 20t human life cycle of, 702, 702f male See Male reproductive system metabolism in, 126 prostaglandin actions in, 352 sexual reproduction, 702–708 timetable for development of, 706, 708t Residual body, 717 Residual volume, 540, 542, 542t Resistance, to blood flow, 463–465, 464–465f, 464t Resistance stage, in stress response, 340 Resistance training, 384 Resistance vessels, 455 Resistin, 671 Resolution phase, of sexual response, 712 Resolving power, of visual system, 296 Resorption, bone, 690–692, 691f Respiratory acidosis, 568, 568–569t, 569 Respiratory alkalosis, 568, 568–569t, 569 Respiratory assemblies, 115 Respiratory bronchioles, 534 Respiratory complexes, 113 Respiratory component, of acid-base balance, 568– 569, 568–569t Respiratory control centers, 230, 230f, 231, 553–559, 554–557f Respiratory distress syndrome (RDS), 540 Respiratory group, 554 Respiratory system, 532–575 See also Ventilation cell concepts related to, 83 ciliated epithelial cells in, 55 disorders of, 544–546 functions of, 20t membrane transport in, 157 metabolism in, 126 prostaglandin actions in, 352 structure of, 533–536, 533–536f thoracic cavity, 536, 537f Respiratory zone, 534–536, 535f Rest and digest response, of parasympathetic nervous system, 251 Restenosis, 469 Resting membrane potential (rmp), 152–153, 152– 153f, 172–173 Resting sleep, 214 Resting tremor, 391, 391t I-28 Index Restrictive disorders, 544 Rete testis, 713f, 718 Reticular activating system (RAS), 231–232, 231f Reticular formation, 231 Reticulocytes, 411 Reticulospinal tracts, 234t, 235, 390 Retina See also Cones; Rods color vision, 301, 303, 303f dark adaptation, 300–301, 301–302f electrical activity of, 300–301 light passing through, 293–294, 294f location and composition of, 291t, 298, 298f neural pathways from, 304–306, 305–306f visual acuity and sensitivity, 304 Retinaldehyde, 299–300 Retinal (pigment) See Retinaldehyde Retinal pigment epithelium, 298–299, 300 Retinene See Retinaldehyde Retinitis pigmentosa, 300 Retinohypothalamic tracts, 228, 347 Retinoic acid, 666 Retinoic X receptor (RXR), 324, 325 Retinol, 666 Retinol binding protein, 671 Retrograde messengers, 224 Retrograde neurotransmitters, 197 Retrograde transport, 62, 165 Retrotransposons, 63 Retrotrapezoid nucleus, 554 Retroviruses, 509 See also HIV/AIDS Reuptake, of monoamines, 191, 191f Reverberating circuits, of neuronal activity, 222 Reverse chloride shift, 566–567, 566f Reverse transcriptase, 78, 509 Reverse transcriptase inhibitors, 509 Reversible chemical reactions, 95 Reversible reactions, 95 Reward system, cerebral areas related to, 219–220, 229 Rhabdomyolysis, 380 Rheumatic endocarditis, 420–421 Rheumatic fever, 522, 522t Rheumatoid arthritis, 521, 522, 522t, 523 Rheumatoid factors, 523 Rh factor, 413–414 Rhinencephalon See Limbic system Rhinitis, allergic, 523 Rh negative, 413–414 Rhodopsin, 299, 299–300f, 300 RhoGAM, 414 Rhombencephalon See Hindbrain Rh positive, 413–414 Rhythmicity center, 554 Rhythm method, of contraception, 733 Riboflavin See Vitamin B2 Ribonuclease, 91t Ribonucleic acid See RNA Ribonucleotides, 46–47 Ribose, 46, 46f Ribosomal RNA (rRNA), 46, 63, 66 Ribosomes, 52t, 60, 60f, 68 Ribozymes, 60, 89 Rickets, 695 Right hemisphere, of brain, 209 Right lymphatic duct, 443, 444f Rigor complexes, 368 Rigor mortis, 368 Ringer, Sidney, 370 Ringer’s lactate, 141 RISC (RNA-induced silencing complex), 67 Rituximab, 520 Rivaroxaban (Xarelto), 423 rmp (resting membrane potential), 152–153, 152– 153f, 172–173 RNA-induced silencing complex (RISC), 67 RNA interference (RNAi), 67 RNA polymerase, 65 RNA (ribonucleic acid) enzymatic activity of, 89 genome codes for, 63 structure of, 46–47, 46f synthesis, 64–65 types of, 46, 63, 65–67, 68–69, 70f Rodbell, Martin, 5t Rods, 298, 299–300, 299f Rofecoxib, 352 Roloxifene (Evista), 693 Rosiglitazone (Avandia), 684 Rotational acceleration, 279 Rough (granular) endoplasmic reticulum, 60 Round window, 285 rRNA (ribosomal RNA), 46, 63, 66 Rubrospinal tracts, 234t, 235 Ruffini endings, 270, 270t Rugae, 625 RXR (retinoic X receptor), 324, 325 Ryanodine receptors, 371 S Saccadic eye movements, 306 Saccharin, 276 Saccule, 279, 280 Sacral nerves, 236 Sacral plexus, 236f SAD (seasonal affective disorder), 348 St John’s Wort, 192 Salbutamol (Albuterol), 255, 256t Saline solutions, 140, 141 Saliva, 93 Salivary amylase, 93, 623, 650 Salivary glands, 15, 258, 621 Salk vaccine, 517 Salt See also Sodium blood volume and, 460f, 461, 462, 463f historical value of, 461 hypertension and, 483–484 intestinal absorption/transport of, 634 reabsorption by kidneys, 590–598, 591f Saltatory conduction, 180 Salty taste, 275, 275f, 276 Sarcolemma, 360–361 Sarcomeres, 365–367f, 366–367, 392, 453 Sarcopenia, 384 Sarcoplasmic/endoplasmic reticulum Ca21 ATPase (SERCA) pumps, 373 Sarcoplasmic reticulum, 368, 371–372, 372f, 373 SA (sinoatrial) node, 425 Satellite cells, 166, 167t, 384 Satiety, 673 Satiety center, 219 Saturated enzymes, 94 Saturated fats, 36, 37, 37f Saturation in carrier-mediated transport, 142, 603 of enzymes, 94, 94f of oxyhemoglobin, 550, 559, 561–562 Saxitoxin, 186, 187t Scala media, 284–285 Scala tympani, 284–285 Scala vestibuli, 284–285 Scalenes, 541 Schally, Andrew, 5t Schizophrenia, 193 Schlemm, canal of, 293 Schwann cells, 166, 167–168, 167t, 169 SCID (severe combined immunodeficiency disease), 95 Science (journal), Scientific method, 2–4 Sclera, 290, 291t Scleral venous sinus, 293 Scleroses, 168 Sclerotherapy, 436 SCN (suprachiasmatic nuclei), 227–228, 347–348 S cones, 303, 303f Scrotum, 705, 706 Seasonal affective disorder (SAD), 348 Sebaceous glands, 15, 18, 20 Sebum, 18 Secondary active transport, 146–147, 146f Secondary adrenal insufficiency, 338 Secondary (flower-spray) endings, 386 Secondary hypertension, 482, 483t Secondary immune response, 515, 515f Secondary lymphoid organs, 499–500 Secondary lysosomes, 58 Secondary sensory endings, 386 Secondary sex characteristics, 711 Secondary spermatocytes, 716 Secondary structure, of proteins, 42f, 43 Second-degree AV node blocks, 442 Second law of thermodynamics, 98, 134 Second messengers adenylate cyclase–cyclic AMP system, 155, 192, 326–328, 327f, 328t explanation of, 155, 192 in fertilization, 735 gap junctions and, 181 in hormone action, 326–331 in neurotransmission, 192, 254 in olfaction, 276–277, 278f phospholipase C–Ca21 system, 328–329, 329f, 330t in taste sensations, 276 tyrosine kinase system, 329–331 Second sound, of heart, 420 a-Secretase, 222 b-Secretase, 222 g-Secretase, 222 Secretin, 645, 649–650 Secretion See also specific sites and substances explanation of, 599, 599f gastric phases of, 645–648, 646t plasma clearance and, 599–600 pulsatile, 322, 709 Secretory phase, of endometrium, 731–732 Secretory vesicle, 51f, 55 Segmentation, of small intestine, 620, 631–632 Seizures, 196, 197 Selective estrogen receptor modulators (SERMs), 325 Selective permeability, 132, 136 Selenium, recommended dietary allowance for, 665t, 668 Self-antigens, 517 Selye, Hans, 5t, 340 Semantic memory, 220, 221, 221t Semen, 721–722, 722f Semicircular canals, 279, 280–281, 281f Semicircular duct, 280 Index Semiconservative replication of DNA, 73–74 Semilunar valves, 419–420, 420f Seminal vesicles, 16, 706, 719 Seminiferous tubules, 349, 705, 713, 713f Senescence, 78 See also Age and aging Senile plaques, 221–222 Sensation, 266–308 adaptations of, 268, 306 categories of, 267–268, 268t characteristics of, 267–269 cutaneous sensations, 268, 270–274, 270t, 271f, 273–274f, 273t ears and hearing, 282–290, 283–289f eyes and vision, 290–308 See also Eyes; Vision generator potentials, 269, 269f lateral inhibition and, 273, 274f law of specific nerve energies, 268–269 receptive fields and sensory acuity, 272–273 smell, 276–278, 277–278f somatesthetic sensations, 210, 271–272 taste, 274–276, 275f vestibular apparatus and equilibrium, 278–282, 279–282f Senses, special, 268 Sensitivity, visual, 304, 304–305f Sensorineural deafness, 289 Sensors, in negative feedback loops, Sensory acuity, 272–273 Sensory adaptation, 268, 306 Sensory (afferent) neurons, 164t, 165, 207 Sensory receptors categories of, 267–268 characteristics of, 267–269 cutaneous, 268, 270–274, 270t, 271f olfactory, 209, 274, 275, 276–278, 278f phasic, 268, 268f potentials of, 269, 269f receptive fields of, 272–273 taste, 274–276 tonic, 268, 268–269f visual See Cones; Rods Sepsis, 510 Septal defects, 421, 421f Septal nuclei, 219 Septic shock, 486, 510 Septum, of heart, 418 SERCA (sarcoplasmic/endoplasmic reticulum Ca21 ATPase) pumps, 373 Series-elastic component, 376 Serine, 122t SERMs (selective estrogen receptor modulators), 325 Serosa, gastrointestinal, 622 Serotonin in blood clotting, 414 in drug abuse, 192 functions of, 192 in gastrointestinal regulation, 648 as neurotransmitter, 191, 192, 196t receptors for, 185, 192 secretion of, 409, 625, 648 Serotonin-specific reuptake inhibitors (SSRIs), 192 Serotonin transporter (SERT) proteins, 192 Sertoli cells See Sustentacular cells Serum, 407 Set points, 6–7, 7f Severe combined immunodeficiency disease (SCID), 95 Sex, growth as function of, 711, 711f Sex characteristics, secondary, 711–712, 711t, 715t Sex chromosomes, 79, 703–704 Sex determination, 702–705 Sex drive, 219 Sex organs, accessory, 705–706, 706–707f, 718–719 Sex steroids biosynthetic pathway for, 319f, 709, 709f in hypothalamus-pituitary-gonad axis, 336, 336f negative feedback effects of, 708–709 from placenta, 744, 744f, 744t in puberty, 707, 710, 711 secretion of, 40, 320, 322, 349, 709 Sexual reproduction, 702–708 Sexual response, 712 Sheath myelin, 167–169, 167–169f of Schwann, 167 Shell, of electrons, 25–26 Shellfish poisoning, 186 Sherrington, Charles, 5t Shivering, 7, 7f, 227 Shock anaphylactic, 486 cardiogenic, 486 circulatory, 484–486, 485t hypovolemic, 484, 486 neurogenic, 486 septic, 486, 510 spinal, 260, 390 Shock-wave lithotripsy, 584 Short-chain fatty acids, 634 Shortening contractions, 376 Short feedback loops, 336 Short interfering RNA (siRNA), 67 Short-term memory, 220 Shunting, 465 Sickle-cell anemia, 564, 564f SIDS (sudden infant death syndrome), 558 Sigmoid colon, 633 Signaling cellular, 153–156, 154f endocrine, 154 local, 154 paracrine, 154 synaptic, 154 Signaling complexes, 427 Signaling molecules, 330–331 Signal-transduction mechanisms, 326 Sildenafil (Viagra), 721 Simple cortical neurons, 308, 308f Simple diffusion, 133 Simple epithelium, 12, 13t Single covalent bonds, 30, 31f Single photon emission computed tomography (SPECT), 213t Single-unit smooth muscles, 394, 395f Singulair (montelukast), 352, 545 Sinoatrial conduction pathways, 426 Sinoatrial (SA) node, 425 Sinus bradycardia, 440f Sinuses carotid, 477 scleral venous, 293 urogenital, 706 Sinusoids, 434, 636 Sinusoids, hepatic, 636–637, 637–638f Sinus tachycardia, 440 siRNA (short interfering RNA), 67 Skeletal muscle pumps, 435 Skeletal muscles, 360–391 actions of, 360, 360t adaptations to training, 383–384, 383t I-29 agonist, 360 anaerobic metabolism and, 109–110 antagonist, 360, 385t, 389–390, 389f blood flow through, 470, 470t comparison with cardiac and smooth muscles, 397t contraction, 364–377 See also Contraction of skeletal muscles Cori cycle and, 117–119, 118f damage and repair of, 384 drugs affecting neural control of, 185, 187t energy requirements and sources for, 123, 125t, 377–384 exercise training adaptations, 382–384, 383t fatigue of, 381–382 fibers within, 11, 11f, 380–381, 381–382f, 381t glucose production in, 117 hypertrophy, 384 metabolism of, 378–380, 378–380f motor neuron control of, 235, 235f, 361–364, 362–363f neural control of, 384–391, 385t reflexes, 238–239, 387–390, 388–390f, 388t relaxation of, 373 stretching of, 387–390 striations in, 11, 11f, 361, 361f, 365, 365–366f structure of, 360–361, 361f tone of, 387 Skeletal system, 20t, 157 See also Skeletal muscles Skin architecture of, 18–19, 19f blood flow to, 474–475, 475f cutaneous sensations, 268, 270–274, 270t, 271f, 273–274f, 273t dermis of, 18 endocrine functions of, 318t epidermis of, 14, 18 epithelial linings of, 14 exocrine function of, 18 hypodermis of, 18 nerve endings in, 20 pigment of, 20 Skin cancer, 76 Skin test for allergies, 524, 525f Sleep, 214–215, 220, 231–232, 231f Sleep apnea, 558 SLE (systemic lupus erythematosus), 521, 522t, 523 Sliding filament theory of contraction, 367–369, 367t, 368f Sling surgery, 584 Slit diaphragm, 587 Slow component, in axonal transport, 164 Slow oxidative fibers, 380 Slow-twitch fibers, 380–381, 381–382f, 381t Slow waves, in small intestine, 631–632, 632f Slow-wave sleep, 214 Small intestine, 318t, 621, 628–632, 629–632f Small nuclear ribonucleoproteins (snRNPs), 67 Smallpox, 504, 514–516 Smell, 276–278, 277–278f Smoking, 544, 545, 546 Smooth (agranular) endoplasmic reticulum, 60, 61 Smooth muscles adrenergic regulation of, 252, 254 autonomic innervation of, 244, 394–395 blood flow and, 466 characteristics of, 11, 11f, 12, 393–394 comparison with skeletal and cardiac muscles, 397t contractile apparatus of, 394, 394f excitation-contraction coupling in, 393, 393f, 395–396, 396f I-30 Index Smooth muscles—Cont latch state of, 396 layers of, 393 multiunit, 394, 395f myogenic activity of, 394 nitric oxide and, 258 prostaglandins and, 351 relaxation of, 395 single-unit and multiunit, 394, 395f tone of, 245 Smooth pursuit eye movements, 306 SNARE complex, 183 Snellen eye chart, 296 S-nitrosohemoglobin (SNO), 467 SNO (S-nitrosohemoglobin), 467 snRNPs (small nuclear ribonucleoproteins), 67 SnRNPs (small nuclear ribonucleoproteins), 67 Sodium See also Salt active transport of, 145–146, 145f cotransport with glucose, 146, 146f equilibrium potential, 151 excretion of, 462 homeostasis of, 608, 608f ionic bonds with chloride, 27, 28f loss through sweat, 461 normal range in blood, 6t potassium and, 608, 608f reabsorption of, 605 renal regulation of, 604–606 Sodium channels, 135–136, 172–176, 174–176f, 426 Sodium chloride, 27, 28f, 139 Sodium citrate, 418 Sodium hydroxide, 29t Sodium-potassium pumps, in active transport, 145– 146, 145f, 153, 175–176 Soleus muscle, 381, 381f Soleus muscle pump, 436 Solifenacin, 258 Solutes, 134, 134f, 136 Solutions acidic, 29–30 alkaline, 29, 30 components of, 134 dextrose, 140, 141 hypertonic, 140, 141f hypo-osmotic, 140 hypotonic, 140, 141f isosmotic, 140 isotonic, 140, 141f neutral, 29 one-molal, 139, 139f one-molar, 138, 139f saline, 140, 141 tonicity of, 140, 141f Solvents, 134 Somatesthetic sensations, 210, 271–272 Somatic cell nuclear transfer, 738 Somatic hypermutation, 505, 512, 516, 521 Somatic motor neurons, 164t, 165, 238, 238f Somatic nervous system, 244, 245t Somatomammotropin, 349, 743–744 Somatomedins, 688 Somatosensory cortex, 210, 271 Somatostatin, 196t, 332, 335, 647 Somatotropin See Growth hormone (GH) Sound See also Hearing frequency of, 283, 285–286, 286f, 288–289, 288–289f of heart, 420–421, 421f intensity of, 283 pitch, 283, 285–286, 286f, 288–289 Sounds of Korotkoff, 480, 480f Sound waves, 282–283 Sour taste, 275, 275f, 276 Space travel, 384, 691 Spasms, muscle, 363, 387 Spastic paralysis, 183, 390, 391t Spatial summation, 199, 199f Special senses, 268 Specific immunity See Adaptive immunity Specificity of antibodies, 412, 498, 502, 504 in carrier-mediated transport, 142 of enzymes, 89, 90f of hormones, 323 SPECT (single photon emission computed tomography), 213t Speech cerebral areas involved in, 218, 218f recovery after brain injury, 218 Sperm, 56 acrosome, 735 capacitation, 734 fertilization by, 702, 735–737, 735–737f flagella of, 56, 734–735 production of, 332, 349 Spermatids, 716 Spermatocytes, 716, 716f Spermatogenesis, 705, 709, 715–716, 716f, 718 Spermatogonia, 704 Spermatozoa, 716, 717–718f, 718 Spermiogenesis, 717, 717f Sperry, Roger, 5t S phase, 74 Sphincters lower esophageal, 624 of Oddi, 640 precapillary, 433 pyloric, 625, 645 urethral, 584 Sphygmomanometers, 476, 480 Spike potentials, 176 See also Action potentials Spinal cord central canal of, 208 structure of, 207, 207f tracts of, 232–235, 233–234t, 234–235f Spinal nerves, 163, 236, 236f, 238–239, 385 Spinal shock, 260, 390 Spindle apparatus, 57 Spindle fibers, 76 Spinothalamic tract, 272 Spiral arteries, 731, 741 Spiral organ (organ of Corti), 286–288, 287f Spirogram, 542, 543f Spirometry, 542 Spironolactone (Aldactone), 612 Splanchnic nerves, 247 Spleen, 444, 444f, 495, 499 Spliceosomes, 67 Split-brain procedures, 216–217 Spongy urethra, 706 Spontaneous depolarization, 425 Sporadic ALS, 385 Sports drinks, 461 Squamous cell carcinoma, 76 Squamous epithelium, 12, 13t, 14f SQUIDS (superconducting quantum interference devices), 213 SRY gene, 705 SSRIs (serotonin-specific reuptake inhibitors), 192 Staircase effect, 375 Stapedius muscle, 284 Stapes, 284 Starch, 34, 36, 36f, 650 Starling, Ernest, 5t Starling forces, 457 Starvation, 671 Statin drugs, 438 Statistics, in scientific research, Stem cells adult, 19–20, 64, 739 basal, 276 embryonic, 19, 64, 738–740 hematopoietic, 64, 409, 411 intestinal, 629 melanocyte, 20 mesenchymal, 64 neural, 64, 209, 224 Stents, 469 Stereocilia, 280, 287 Stereoisomers, 32–33, 32f Sternocleidomastoid muscles, 541 Steroid and xenobiotic receptor (SXR), 641 Steroid family, of hormone receptors, 324 Steroid hormones anabolic, 322, 714 biosynthetic pathway for, 337, 339f, 709, 709f concentrations and tissue response, 322 conjugation of, 641 diffusion through plasma membrane, 135 genomic action of, 324 hydroxylation of, 641 inactivation of, 61 mechanism of action, 323f, 324–325 negative feedback effects of, 709 from placenta, 744, 744f, 744t receptors for, 155, 323f, 324–325 secretion of, 320, 337, 707, 709 structure of, 40, 40f Steroids, anabolic, 322, 714 Stethoscope positions, 420, 421f Stimulus intensity coding, 176, 176f Stomach, 318t, 621, 625–628, 625f Stones gallbladder, 642 kidney, 584 Strabismus, 363 Stratified epithelium, 12, 13t, 14f Stratum functionale, 723, 731 Streptococcus infections, 522 Streptokinase, 417 Stress adrenal gland and, 340–341 cancer and, 521 effects on menstrual cycle, 732–733 oxidative stress, 114, 668–669 Stress hormones, 340 Stress hyperglycemia, 679 Stress urinary incontinence, 584 Stretch reflexes, 387–388, 388t, 479 Striate cortex, 306, 306f, 308 Striated muscles, 11, 11f, 361, 361f, 365, 365–366f Stroke, 218, 417 anabolic steroids and, 322 autonomic dysreflexia, 260 COX inhibitors and, 352 etiology of, 440 excitotoxicity in, 200 hypertensive, 484 treatment of, 440 Stroke volume, 423, 451, 452–454, 476 Index Structural isomers, 33 Structural proteins, 44 Struvite stones, 584 Strychnine, 187t, 195 S-T segments, 428, 429f Subarachnoid space, 208 Subatmospheric (negative) pressure, 538 Subclavian veins, 443, 444f Subcutaneous fats, 671 Subgranular zone, 209 Submandibular ganglion, 250 Submucosa, gastrointestinal, 622 Submucosal plexus, 622 Substance P, 196, 196t Substantia nigra, 193, 215–216, 228, 391 Substrate-level phosphorylation, 115 Substrates, 89, 91, 94–95, 94f Subthalamic nucleus, 216, 391 Subventricular zone, 209 Sucrose, 34, 138 Sudden death, from cardiac arrhythmias, 441 Sudden infant death syndrome (SIDS), 558 Sugars, 33, 34 Sulci, 210 Sulfhydryl groups, 32f Sulfonylurea, 684 Sulfur, atomic structure of, 25t Sulfuric acid, 29t Summation, 185, 374–375, 374f Superconducting quantum interference devices (SQUIDS), 213 Superior colliculi, 228, 306 Superior mesenteric ganglia, 247 Superior olive, 288 Superior vena cava, 419 Superoxide dismutase, 385 Superoxide radicals, 114, 668 Supplementary motor cortex, 233 Supporting cells See Neuroglial (glial) cells Suppressor T lymphocytes See Regulatory T lymphocytes Suprachiasmatic nuclei (SCN), 227–228, 347–348 Supraoptic nuclei, 227, 333 Surface active agent, 540 Surface tension, 29, 539 Surfactants, 39, 540, 540f Surveillance, immunological, 519–520 Suspensory ligament, 293 Sustentacular (Sertoli) cells, 276, 557, 705, 716–718 Sutherland, Earl, 5t Svedberg units, 60 Swallowing, 620, 623 Swallowing center, 624 Sweat glands, 15, 18, 259t, 260 Sweating, 7, 475 Sweet taste, 275, 275f, 276 Swelling See Edema SXR (steroid and xenobiotic receptor), 641 Sympathetic chain of ganglia, 246, 246–247f Sympathetic nervous system aging and, 261 blood flow regulation by, 466, 467t divergence and convergence in, 246–247 functions of, 251 gastrointestinal regulation by, 622 glomerular filtration and, 589 glucagon secretion and, 679 insulin secretion and, 679 mass activation of, 247, 251 neurotransmission in, 190, 194, 251–254, 252– 253f, 255f parasympathetic nervous system and, 248, 258– 260, 259t postganglionic fibers of, 246, 247 preganglionic fibers of, 246, 247 Sympathetic neurons, 165 Sympathetic ophthalmia, 522, 522t Sympathoadrenal system, 247, 260, 339, 340, 454, 470, 675 Sympathomimetic drugs, 251 Sympathomimetic toxicity, 251 Symport, 146–147, 146f Synapses, 154, 180–183, 181–182f, 184f Synapses en passant, 252, 395 Synaptic clefts, 181–182 Synaptic depression, 199–200 Synaptic inhibition, 200–201, 200f Synaptic integration, 199–201 Synaptic plasticity, 199–200 Synaptic potentials, 183, 184f, 213 Synaptic signaling, 154 Synaptic transmission adrenergic, 251–252, 252–253f calcium in, 181, 182–183, 182f, 200, 201 cholinergic, 251–252, 252–253f inhibition of, 199–201 long-term depression in, 197, 199–200 long-term potentiation in, 199–200 in memory, 222–224, 223f Synaptic vesicles, 182–183, 182f Synaptobrevin-2, 183 Synaptotagmin, 183 Syncytiotrophoblast, 741 Syncytium, 11 Syncytium, functional, 425, 428 Synergistic effects, of hormones, 321 Syntaxin, 183 Synthases, 91 Synthetases, 91 a-Synuclein, 216 Systemic circulation, 418–419, 419f, 419t Systemic lupus erythematosus (SLE), 521, 522t, 523 Systems See also specific systems explanation of, 11, 20 organ, 20, 20t Systole, 420, 422 Systolic pressure, 479 Szent-Györgyi, Albert von, 5t T T3 See Triiodothyronine Tachycardia, 440 Tactile acuity, 273 Tadalafil (Cialis), 721 Tagamet, 627 Tamoxifen, 325 Tanning, 18 Target cells, 154, 317, 323 Target organs, Taste, 274–276, 275f Taste buds, 274, 275f Taste cells, 275, 275f Tau protein, 222 Tay-Sachs disease, 58, 97t TBG (thyroxine-binding globulin), 325 TCA (tricarboxylic acid) cycle, 107, 111–112, 112–113f I-31 TDF (testis-determining factor), 704, 704f Tear (lacrimal) glands, 15 Tectal system, 306, 307 Tectorial membrane, 287 Tectospinal tracts, 234t Teeth, 18, 18f, 621 Telencephalon, 207–208, 208f, 225 See also Cerebrum Telmisartan, 462 Telomerase, 78 Telomeres, 76, 78 Telophase of cell cycle, 76, 77f, 79, 80f, 81t Temperature See also Body temperature control center, 662 enzymes, effect on, 92, 92f negative feedback control with, 92, 92f oxygen transport and, 562 receptors for, 270 regulation of, 405 Temporal lobe, 210, 211–212, 211t Temporal summation, 199 Tendons, 16 Tension-length relationship, in muscle contraction, 376–377, 377f Tensor tympani muscle, 284 Teratogenic effects, 33 Terbutaline, 255, 256t Teriparatide (Forteo), 693 Terminal boutons, 181 Terminal bronchioles, 535–536 Terminal cisternae, 371 Terminal ganglia, 248 Tertiary structure, of proteins, 42–43f, 43 Testable hypotheses, Testes compartments of, 713, 715, 715f endocrine functions of, 349, 707, 714–715 exocrine functions of, 16 formation of, 704–705, 704f immunologically privileged site in, 514, 717 paracrine regulation in, 715 puberty and, 711 sex steroid secretion by, 40, 709 undescended, 705 Testicular feminization syndrome, 707 Testis-determining factor (TDF), 704, 704f Testosterone actions of, 349, 714, 715t chemical structure of, 40f derivatives of, 714, 714f puberty and, 711, 714–715 regulation of bone and, 692 secretion of, 349, 705, 714 Tetanus, 374–375, 375f Tetanus toxin, 183 Tetany, 375 Tetracaine, 175 Tetrahydrocannabinol (THC), 197–198 Tetraiodothyronine (T4) See Thyroxine Tetrodotoxin, 186, 187t TGFb (transforming growth factor beta), 508, 520 Thalamus, 216, 225–226, 391 Thalassemia, 564 Thalidomide, 33 TH1 cells, 509 TH2 cells, 509 TH17 cells, 509 THC (tetrahydrocannabinol), 197–198 Theca interna, 725, 725f Theophylline, 328 I-32 Index Theoretical ATP yield, 116 Theories, Thermic effect of food, 675 Thermodynamics, first and second laws of, 97–98, 134 Thermogenesis, 120–121, 674–675 Thermoreceptors, 267 Thermoregulation, 474 Thermotaxis, 735 Theta waves, 214, 214f Thiamine See Vitamin B1 Thiazide diuretics, 611t, 612 Thiazolidinediones, 685 Thick filaments, 365, 365–366f Thin filaments, 365, 365–366f Third-degree AV node blocks, 442 Third ventricle, 225 Thirst centers, 226, 460, 461 Thoracic aortic aneurysms, 432 Thoracic cavity, 536, 537f Thoracic duct, 443 Thoracic muscles, 541–542, 541f Thoracic nerves, 236 Thoracic veins, 436, 455 Thoracolumbar nervous system See Sympathetic nervous system Threonine, 122t Thrombin, 416 Thrombocytes See Platelets Thrombocytopenia, 411, 484, 522 Thrombocytosis, 410 Thrombolytic agents, 417 Thrombopoietin, 410–411 Thrombosis, coronary, 414, 417 Thromboxane A2, 351, 414 Thrombus, 436 Thymine, 45, 45f, 63 Thymus, 318t, 499 Thymus-dependent cells See T lymphocytes Thyrocalcitonin See Calcitonin Thyroglobulin, 342 Thyroid follicles, 341 Thyroid gland, 318t, 341–342f, 341–343 Thyroid hormone family, of receptors, 324 Thyroid hormones abnormal levels of, 342–343, 344t in bone physiology, 692 mechanism of action, 325, 342 receptors for, 155, 323–325, 326f structural formulas for, 320, 320f synthesis of, 341, 343f Thyroiditis, 521, 522, 522t Thyroid-stimulating hormone (TSH), 332, 332t, 333–334, 342–343 Thyrotropin-releasing hormone (TRH), 42, 196t, 335 Thyroxine, 320, 325, 341, 342, 686–687 Thyroxine-binding globulin (TBG), 325 TIAs (transient ischemic attacks), 218 Tidal volume, 542, 542t Tight junctions, 147 TIL (tumor-infiltrating lymphocyte), 520 Tinnitus, 282 Tissue factor, 416–417 Tissue (interstitial) fluid, 20–21, 131, 705 Tissue plasminogen activator (t-PA), 417 Tissues See Primary tissues Tissue thromboplastin See Tissue factor Titin, 367, 367f, 384 T lymphocytes activation of, 510–511, 510f aging and, 499 antigen-presenting cells and, 510, 510–513f, 510–514, 510f autoreactive, 517–518, 521 cancer cell destruction by, 519–520, 520f in clonal selection theory, 515–516 comparison with B lymphocytes, 499, 500t helper, 508, 509, 511–512, 511–513f in hypersensitivity reactions, 523, 526 killer, 507–508, 511–512, 511–513f, 519–520 local inflammation and, 502 regulatory, 508, 518 viruses, response to, 512, 512f a-Tocopherol See Vitamin E Tolerance central, 518 to drugs, 61 immunological, 517–518 peripheral, 518 Toll-like receptors, 495, 500, 517 Toll receptors, 495 Tomography computed, 212, 213t positron-emission, 192, 212, 213t Tone of cardiac muscles, 245 of skeletal muscles, 387 of smooth muscles, 245 Tongue, 274–275, 275f, 621 Tonicity, 140, 141f Tonic receptors, 268, 268–269f Tonotopic organization, 289 Tonsils, 444, 499 Tooth See Teeth Torr, 544t, 547 Torricelli, Evangelista, 547 Total blood volume, 451 Total minute volume, 542, 542t Total peripheral resistance, 452, 465, 476 Total renal blood flow, 603 Totipotent cells, 19 Touch, receptors for, 270, 272–273, 273–274f, 273t Toxemia of pregnancy, 333, 484 Toxins, 495 t-PA (tissue plasminogen activator), 417 Trace elements, 668 Trachea, 535–536 Tracheostomy, 536 Tracheotomy, 536 Tract, in nervous system, 164t, 166 Training See Endurance training; Resistance training Transaminase, 91t Transamination, 122–123, 122f Transcellular transport, 147–148 Transcription factors, 65, 75, 323–324 Transdifferentiation, 740 Transducins, 301 Transduction, sensory, 267 Trans fats, 37, 37f Transferrin, 408, 412 Transfer RNA (tRNA), 46, 66, 68–69, 70f Transforming growth factor beta (TGFb), 520 Transfusion reactions, 412–413 Transient ischemic attacks (TIAs), 218 Transient receptor potential (TRP) channels, 271 Transitional epithelium, 13t Translation, genetic, 63, 68–71, 69f, 71f Transmural (transpulmonary) pressure, 538, 538t Transplants, stem cell, 411 Transport See also Carrier-mediated transport active, 132, 133, 144–148, 145–148f, 590–591 axonal, 164–165 bulk, 54–55, 148–149, 149f coupled, 146–147, 146f in epithelial membranes, 147–148, 147–148f non-carrier-mediated, 133 paracellular, 147–148 passive, 133, 133f, 144, 590–591 in plasma membranes, 132–133, 133f renal clearance and, 599–600 retrograde, 62, 165 transcellular, 147–148 Transport maximum, 142, 603 Transpulmonary pressure, 538, 538t Trans sterioisomers, 32, 32f Transurethral resection (TUR), 719 Transverse colon, 633 Transverse (T) tubules, 371–373 Trastuzumab (Herceptin), 325, 518, 520 Tremors, 230, 391, 391t Treppe, 375 TRH (thyrotropin-releasing hormone), 42, 196t, 335 Triacylglycerol, 36 See also Triglycerides Triamterene (Dyrenium), 612 Tricarboxylic acid (TCA) cycle, 107, 111–112, 112–113f Trichromatic color vision, 303, 303f Tricuspid valve, 419 Tricyclic antidepressants, 194 Trigeminal nerve, 230, 237t Triglycerides absorption of, 653 in adipose cells, 58 aggregations of, 58 digestion of, 652–653, 653f exercise and, 379, 383 formation of, 36, 38f, 119–120 secretion by liver, 641 Triiodothyronine (T3), 320, 325, 326f, 342 Tripeptides, 41 Triple reuptake inhibitors, 194 Tritanopia, 303 Tritium, 26 tRNA (transfer RNA), 46, 66, 68–69, 70f Trochlear nerve, 237t Trophic hormones, 331–332, 650 Trophoblast cells, 738 Tropomyosin, 370–371, 371f Troponin, 370–371, 371f, 392 Troponin C, 370, 392 Troponin I, 370, 392 Troponin T, 370, 392 TRP (transient receptor potential) channels, 271 Trypsin, 93, 631, 643, 651 Trypsinogen, 643, 644f Tryptophan, 122t, 192, 319 TSH (thyroid-stimulating hormone), 332, 332t, 333–334, 342–343 T4 (tetraiodothyronine) See Thyroxine T tubules, 371–373, 372–373f Tuberculosis, 526 Tubocurarine See Curare Tubules dentinal, 18 mammary glands, 745f, 746 microtubules, 52t, 55, 57, 57f nephron, 585, 586–587 seminiferous tubules, 349, 705, 713, 713f transverse, 371–373 Tubuloglomerular feedback, 589 Index Tufted cells, 278 Tumor-infiltrating lymphocyte (TIL), 520 Tumor necrosis factor, 497, 501, 670 Tumors See also Cancer angiogenesis and, 435 benign, 518 dedifferentiation of cells in, 519 immunology of, 519–521 malignant, 519 natural killer cells and, 520–521 Tumor suppressor genes, 67, 75 Tunica externa, 431 Tunica interna, 431 Tunica media, 431 Turbulent flow, 479–480 Turner’s syndrome, 705 Turnover, of enzymes proteins, 94 Turnover rate, 665 TUR (transurethral resection), 719 T waves, 428, 429f 20/20 vision, 296 Twins, 736 Twitch, 374–375, 374f Two-point touch threshold, 272–273, 273f, 273t Tylenol, 352 Tympanic membrane (eardrum), 283 Type I diabetes mellitus, 346, 521–522, 522t, 681– 682, 682t, 683f Type I fibers See Slow-twitch fibers Type II diabetes mellitus, 346, 382–385, 382t, 384f Type II fibers See Fast-twitch fibers Tyramine, 192 Tyrosine, 41f, 122t, 191, 319, 329 Tyrosine kinase second messenger system, 329–331 U Ubiquitin, 72 UCP1, 121 Ulcerative colitis, 635 Ulcers duodenal, 627–628 peptic, 352, 628 Ultrafiltrate, 588, 589f Ultrasound, prenatal, 742 Ultraviolet light, 18–19, 76, 290, 290f Umami taste, 275, 275f, 276 Umbilical arteries, 742–743, 743f Umbilical cord banking, 746 Umbilical vein, 742–743, 743f Uncoupling proteins, 121, 675, 686, 687 Unipolar limb leads, 430, 430t Universal donors, 412–413 Universal energy carrier, 99, 100f See also Adenosine triphosphate (ATP) Universal recipients, 413 Unloading reactions, 561 Unmyelinated axons, 167, 168, 168f, 178f, 179 Unmyelinated C fibers, 558 Unsaturated fats, 36, 37f Upper motor neurons, 210, 385, 385t, 387, 390–391, 391t Upregulation, 322 Uracil, 46, 46f Urea clearance of, 602–603 effects of, 594–595, 595f excretion of, 123 normal range in blood, 6t in urine, 594–595, 595f Urea transporters, 594 Uremia, 613 Uremic coma, 613 Ureters, 582, 584 Urethra, 584, 719 Urethral folds, 706 Urethral sphincters, 584 Urgency incontinence, 584 Uric acid, 641 Uric acid stones, 584 Urinary bladder, 258–260, 259t, 582, 584 Urinary buffers, 610 Urinary incontinence, 584 Urinary system cell concepts related to, 83 functions of, 20t membrane transport in, 157 metabolism in, 126 prostaglandin actions in, 352 structure of, 582–583f, 582–584, 585f Urination, 258, 260, 584–585 Urine acidification of, 609, 609f excretion of, 458 glucose in, 143, 604 output of, 590, 597–598 protein in, 588, 613 reabsorption of, 459 urea in, 594–595, 595f Urobilinogen, 639 Urodynamic testing, 584 Urogenital sinus, 706 Uroguanylin, 648 Urokinase, 417 Urticaria (hives), 523 Uterine fibroids, 723 Uterine tubes See Fallopian tubes Uterus contractions of, 8, 333, 744–745, 745f cyclic changes in, 729, 730f, 731 development of, 705 in sexual response, 711 structure of, 723, 723f Utricle, 279, 280 Uvea, 291t V Vaccinations See Immunizations Vacuoles, 52t, 58, 496 Vagina, 14, 711, 723 Vaginal rings, 733 Vagotomy, 650 Vagus nerve in baroreceptor reflex, 477 in breathing regulation, 555 in cardiac regulation, 181, 245, 452 in gastrointestinal regulation, 245, 622, 627, 645, 646, 650 parasympathetic fibers in, 248–250, 249t path of, 250, 250f sensory input from, 260, 261t Vagus nerves, 237t, 248, 250 Vagus nuclei, 231 Vagusstoff, 181 See also Acetylcholine (Ach) Valence electrons, 26 Valine, 41f, 122t I-33 Valium, 196, 229, 232 Valsalva’s maneuver, 479 Valsartan, 462 Valves heart, 419–420, 419–420f venous, 435–436, 435–436f van der Waals forces, 43 Varicose veins, 436 Varicosities, 252, 395 Vasa recta, 593, 594 Vascular endothelial growth factor (VEGF), 305, 434–435, 518 Vascular resistance to blood flow, 463–465, 464– 465f, 464t Vascular tunic, 291t Vas (ductus) deferens, 706, 718 Vasectomy, 722, 722f Vasoactive intestinal peptide (VIP), 258 Vasoconstriction, 432–433, 475–476, 476f Vasodilation, 397, 433, 462, 464–468, 469–472 Vasodilators, 110, 397, 484 Vasomotor control centers, 231, 477 Vasopressin See Antidiuretic hormone (ADH) Vectors, for gene therapy, 95 VEGF (vascular endothelial growth factor), 305, 434–435, 518 Veins abdominal, 435–436, 455 arcuate, 586 central, 637, 637f compliance of, 455 hepatic portal, 636, 637f interlobar, 586 interlobular, 586 pulmonary, 418 renal, 586 subclavian, 443, 444f thoracic, 436, 455 umbilical, 742, 742f varicose, 436 Venous blood, 406 Venous return, 454–455, 455f Venous thromboembolism, 436 Venous valves, 435–436, 435–436f Ventilation (breathing) See also Lungs; Respiratory system acid-base balance and, 569, 569t altitude and, 571–573, 571t, 573f, 573t exercise and, 570–571, 570f, 571t explanation of, 533 inspiration and expiration, 541–542, 541f, 542t intrapulmonary and intrapleural pressures, 537– 538, 538t mechanics of, 540–544, 541f, 543f, 544t partial carbon dioxide pressure and, 555–557, 556–557f partial oxygen pressure and, 557–558, 557f pH and, 555–557, 556–557f physical aspects of, 536–540 pulmonary function tests, 542–544, 542t, 543–544f pulmonary receptors and, 558–559 regulation of, 553–559, 554–557f Ventilation/perfusion ratio, 550–552, 552f Ventral corticospinal tract, 390 Ventral horns, 232 Ventral roots, 238, 385 Ventral tegmental area (VTA), 228 Ventricles, 208, 209f, 418, 422–423, 452–453, 454 Ventricular fibrillation, 440, 441 Ventricular tachycardia, 440 I-34 Index Ventrolateral preoptic nucleus (VLPO), 231 Venules, 406, 431, 455 Verapamil, 397, 426 Vergence movements, 306 Vertical sleeve gastrectomy, 625 Vertigo, 282 Very-low-density lipoproteins (VLDLs), 438, 654 Vesicles, 55, 182–183 Vestibular apparatus, 278–282, 279–282f Vestibular membrane, 285–286 Vestibular nuclei, in equilibrium, 278–282, 279–282f Vestibular nystagmus, 282 Vestibulocochlear nerve, 230, 237t, 280 Vestibulospinal tracts, 234t, 235 Viagra, 198, 721 Villi, 629–630, 630f, 741, 742 Vioxx, 352 VIP (vasoactive intestinal peptide), 258 Virulence, and antigenicity, 515, 515f Viruses See also specific viruses retroviruses, 509 T lymphocyte responses to, 512, 512f Viscera, 621 Visceral effector organs, 244, 245 Visceral fats, 671 Visceral pleura, 536 Visible light, 290, 290f Vision, 290–308 See also Eyes; Retina accommodation in, 295–296, 296f, 307 age-related changes to, 295–296, 305 averted, 304 color, 301, 303, 303f dark adaptation in, 300–301, 301–302f lateral inhibition in, 273, 274f near point of, 295 neural processing of information, 307–308 refraction and, 294, 294–295f resolving power of, 296 sensitivity of, 304, 304–305f 20/20 vision, 296 Visual acuity, 296–297, 304 Visual cycle of retina, 299, 300 Visual field, 294, 295f Visual sensitivity, 304, 304–305f Visuospatial ability, cortical area related to, 217 Vital capacity, 542, 542t Vital centers, 231 Vitalist concept of chemical reactions, 89 Vitamin A, 666–667, 667t Vitamin B1 (thiamine), 666, 667t Vitamin B2 (riboflavin), 101, 666, 667t Vitamin B3 (niacin) characteristics of, 666 functions of, 667t hydrogen carriers and, 100, 101 lipoprotein levels and, 438 recommended dietary allowance for, 665t Vitamin B6 (pyridoxine), 123, 666, 667t Vitamin B12 (cyanocobalamin), 408, 411, 665t, 666, 667t Vitamin C (ascorbic acid), 438, 666, 667t Vitamin D, 667–668, 667t Vitamin D3, 321, 693–695, 694f Vitamin E, 438, 666, 667t Vitamin K, 418, 666 Vitamin K epoxide reductase, 418 Vitamins See also specific vitamins fat-soluble, 666–668 recommended dietary allowances for, 664–665t, 666 sources and functions of, 667t water-soluble, 666 Vitreous body/humor, 293 VLDLs (very-low-density lipoproteins), 438, 654 VLPO (ventrolateral preoptic nucleus), 231 Vocal cords, 536, 536f Voice box (larynx), 536, 536f Voiding reflex, 584 Volatile acids, 568 Voltage, cellular, 150 Voltage-gated calcium channels, 182–183, 372–373 Voltage-gated ion channels, 174, 183 Voluntary muscles See Skeletal muscles Vo2 max, 378 Vomiting, 30 Von Willebrand’s disease, 417 Von Willebrand’s factor, 414 VTA (ventral tegmental area), 228 W WADA (World Anti-Doping Agency), 410 Waist-to-hip ratio, 671 Warfarin (Coumadin), 418, 423 Warming, in respiratory system, 536 Warmth, in inflammation, 502 Warmth receptors, 270 Water in body composition, 25 chemical structure of, 27, 27f hydrogen bonds between, 29, 29f ionization of molecules, 29 osmosis and, 34, 135, 136–137, 137f reabsorption by kidneys, 590–598, 591f surface tension of, 29 Water channels (aquaporins), 135, 137, 594, 596 Water-soluble vitamins, 666 Watson, James, 5t Weight gain, 664, 671 Weightlessness, 384, 691 Weight loss, 664, 670, 671 Wernicke–Korsakoff syndrome, 666 Wernicke’s aphasia, 218 Wernicke’s area, 218, 218f West age-related macular degeneration, 305, 435 Wet brain (Wernicke–Korsakoff syndrome), 666 White adipose tissue, 120, 670 White blood cells See Leukocytes White fibers, 380 White matter, 169, 209 White rami communicantes, 246 WHO (World Health Organization), 148, 671–672 Wilkins, Maurice, 5t Windpipe (trachea), 535–536 The Wisdom of the Body (Cannon), Wolffian (mesonephric) ducts, 705–706 Working memory, 198, 221, 221t World Anti-Doping Agency (WADA), 410 World Health Organization (WHO), 148, 671–672 X Xanax, 196, 232 Xarelto (rivaroxaban), 423 X chromosomes, 703–704, 703f Xenobiotics, 599 X-linked genes, 703 X-ray computed tomography, 212 Y Yawning, 284 Y chromosomes, 703, 703f Yeast, and fermentation, 89 Yohimbine, 256t Z Zantac, 627 Z discs, 366–367, 384 Zinc, recommended dietary allowance for, 665t, 668 Z lines, 361, 365–366 Zollinger-Ellison syndrome, 628 Zoloft, 192 Zolpidem, 229 Zona fasciculata, 337 Zona glomerulosa, 337 Zona pellucida, 725 Zona reticularis, 337 Zonular fibers, 293 Zwischenscheibe (Z) discs, 366–367, 384 Zwischenscheibe (Z) lines, 361, 365–366 Zyflo, 352 Zygotes, 19, 702, 703, 736 Zymogenic (chief) cells, 625 Zymogens, 94 ... called ryanodine receptors; chapter 12, section 12. 2) in a process of Ca21-induced Ca21 release (chapter 12; see fig 12. 34) This produces a massive release of Ca21 from the sarcoplasmic reticulum... Capillaries 0.008 1 ,20 0,000,000 600 0.1 60 Venules 0.03 80,000,000 570 0 .2 110 Terminal veins 1.5 1,800 30 30 Main venous branches 2. 4 600 27 10 27 0 Large veins 6.0 40 11 20 22 0 Vena cava 12. 5 40 50 Terminal... Cross-Sectional Area (cm2) Number Length (cm) Total Volume (cm3) 10 0.8 40 30 Large arteries 40 3.0 20 60 Main artery branches 600 5.0 10 50 06 1,800 5.0 25 Arterioles 0. 02 40,000,000 125 0 .2 25