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After completing chapter 34, you will be able to: Describe the general functions of hormones and the endocrine system; identify the hormones released by the pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, and other hormoneproducing organs, and give the functions of each; explain the effect of stressors on the body; describe the causes, signs and symptoms, and treatments of various endocrine disorders.
CHAPTER 34 The Endocrine System 34-2 Learning Outcomes (cont.) 34.1 Describe the general functions of hormones and the endocrine system 34.2 Identify the hormones released by the pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, and other hormone-producing organs, and give the functions of each 34-3 Learning Outcomes (cont.) 34.3 Explain the effect of stressors on the body 34.4 Describe the causes, signs and symptoms, and treatments of various disorders endocrine 34-4 Introduction • The endocrine system includes the organs that secrete hormones • Hormones – Regulate chemical reactions in cells – Control functions of the organs, tissues, and other cells to n i Glands bloodstream to secrete hormones target tissues 34-5 Hormones • Endocrine glands – Ductless – Release hormones • Directly into target tissues • Into bloodstream to be carried to target tissues • Hormones – chemicals secreted by a cell that affect the functions of other cells 34-6 Types of Hormones • Steroidal Hormones – Cross cell membrane – Bind to receptor in cell nucleus – Hormone-receptor complexes • Turn a gene on or off • Enable cell to carry out functions 34-7 Types of Hormones (cont.) • Nonsteroidal hormones – Cannot cross the membrane – Bind to receptors on the membrane – Hormone-receptor complexes • Activate G-proteins which turn on enzymes • Cell takes on new functions 34-8 Types of Hormones (cont.) • Prostaglandins – Derived from lipid molecules – Target cells are located close by – Produced by organs such as • • • • • Kidneys Heart Stomach Uterus Brain 34-9 Negative and Positive Feedback Loops • Negative feedback loop – hormone release stops in response to decrease in stimulus As body cells take up blood glucose, glucose levels in the blood decline, and insulin release stops (negative feedback) 34-10 Negative and Positive Feedback Loops • Positive feedback loop – as long as stimulus is present, action of hormone continues Milk is released and the baby continues to feed 34-28 The Stress Response • Stressor – Any stimulus that produces stress – Types • Physical factors • Psychological factors • Positive stimuli 34-29 The Stress Response (cont.) • General stress syndrome – Physiologic response to stress – Caused by hormone release – Effects • Increased heart rate, respiratory rate, and BP • Increase in glucose and fatty acids in blood • Increase in cortisol 34-30 Apply Your Knowledge Match the following: ANSWER: A Extreme heat _ A Physical stress B Death of friend _ B Psychological stress A Fractured leg _ C Positive stimulus C Wedding _ B Exam _ B Hearing an explosion nearby _ C “A” on an exam _ A Flu _ B Car stolen _ Common Diseases and Disorders of the Endocrine System Disease/Disorder Description Acromegaly Enlargement of bones and thickened skin Causes: Too much growth hormone produced in adults; tumor of pituitary Addison’s disease Adrenal gland fails to produce enough corticosteroids Cause is unknown – possibly an autoimmune dysfunction; cancer 34-31 Common Diseases and Disorders of the Endocrine System (cont.) Disease/Disorder Description Cushing’s disease Moon face, buffalo hump, thin arms and legs; large abdomen Hypercortisolism Causes: excessive production of ACTH; tumor of the adrenal gland or pituitary gland; long term use of steroids Diabetes insipidus Kidneys fail to reabsorb water, resulting in excessive urination Cause: hyposecretion of ADH 34-32 Common Diseases and Disorders of the Endocrine System (cont.) Disease/Disorder Description Diabetes mellitus Type I Type II Gestational Chronic disease characterized by elevated blood glucose levels Insulin-dependent diabetes mellitus; usually develops in childhood Noninsulin-dependent diabetes mellitus; primarily in adults but increased incidence in teens Occurs during pregnancy; usually temporary 34-33 Common Diseases and Disorders of the Endocrine System (cont.) Disease/Disorder Description Dwarfism Short height, abnormal facial features, cleft lip or palate, delayed puberty Causes: Too little growth hormone produced during childhood; trauma to or tumor of the pituitary gland 34-34 Common Diseases and Disorders of the Endocrine System (cont.) Disease/Disorder Description Gigantism Very tall, delayed sexual maturity, thick facial bones Causes: Too much growth hormone produced during childhood; pituitary gland tumor Goiter Enlargement of thyroid gland, causing swelling in neck Cause: deficiency of iodine in diet 34-35 Common Diseases and Disorders of the Endocrine System (cont.) Disease/Disorder Description Graves’ disease Hyperthyroidism Exophthalmos; goiter Causes: antibodies attack the thyroid gland, causing it to produce too much thyroid hormone; autoimmune disorder 34-36 34-37 Common Diseases and Disorders (cont.) Disease/Disorder Description Cretinism Severe hypothyroidism present prior to or soon after birth Causes: absence or malformation of thyroid gland; abnormal formation of thyroid hormones; pituitary failure Myxedema Severe form of hypothyroidism Causes: removal of thyroid gland; radiation treatments to neck; obesity; may be congenital 34-38 Correct! Apply Your Knowledge True or False: ANSWER: F Acromegaly develops as a result of too much growth hormone in a _ child in an adult T In diabetes insipidus, the kidneys fail to reabsorb water _ T Too little growth hormone in childhood results in dwarfism _ F Myxedema is the result of hyperthyroidism _ hypothyroidism T Addison’s disease is the result of too little corticosteroid _ F Cushing’s disease is the result of too little ACTH _ too much ACTH F Cretinism is an extreme form of hyperthyroidism present at birth _ hypothyroidism 34-39 In Summary 34.1 Endocrine glands are ductless glands, releasing hormones directly into the bloodstream and tissues The organs of the endocrine system produce hormones that regulate the chemical reactions within cells, controlling the functions of organs, tissues, and other cells Hormone levels are controlled by positive and negative feedback loops 34-40 In Summary (cont.) 34.2 The pituitary gland releases: GH, MSH, ACTH, TSH, FSH, LH, PRL, ADH, and OT The thyroid gland releases calcitonin, T 3, and T The parathyroid gland releases PTH The adrenal medulla secretes epinephrine and norepinephrine The adrenal cortex produces aldosterone and cortisol The hormonereleasing of cells in the pancreas release glucagon and insulin The pineal body releases melatonin; the thymus releases thymosin and thymopoietin; ovaries release estrogen and progesterone (females); and the testes (males) release testosterone The kidneys produce erythropoietin, and the heart produces atrial natriuretic peptide 34-41 In Summary (cont.) 34.3 Stressors are stimuli that produce a stress response, a physiologic response to the stimulus that changes the body’s functioning in some way 34.4 The diseases and disorders of the endocrine system are as varied as the organs and hormone dysfunctions that cause them An overview of these conditions is found in Table 342 34-42 End of Chapter 34 Its not stress that kills us, it is our reaction to it ~ Hans Selye .. .34- 2 Learning Outcomes (cont.) 34. 1 Describe the general functions of hormones and the endocrine system 34. 2 Identify the hormones released by the pituitary gland, thyroid gland, parathyroid... parathyroid glands, adrenal glands, pancreas, and other hormone-producing organs, and give the functions of each 34- 3 Learning Outcomes (cont.) 34. 3 Explain the effect of stressors on the body 34. 4 Describe... stressors on the body 34. 4 Describe the causes, signs and symptoms, and treatments of various disorders endocrine 34- 4 Introduction • The endocrine system includes the organs that secrete hormones