Lecture AP Biology Chapter 42B Circulation and gas exchange

After studying this chapter you will be able to: Compare and contrast open and closed circulatory systems; compare and contrast the circulatory systems of fish, amphibians, reptiles, and mammals or birds; distinguish between pulmonary and systemic circuits and explain the function of each; trace the path of a red blood cell through the human heart, pulmonary circuit, and systemic circuit.

LECTURE PRESENTATIONS For CAMPBELL BIOLOGY, NINTH EDITION Jane B Reece, Lisa A Urry, Michael L Cain, Steven A Wasserman, Peter V Minorsky, Robert B Jackson Chapter 42 Circulation and Gas Exchange Lectures by Erin Barley Kathleen Fitzpatrick © 2011 Pearson Education, Inc Chapter 42 Warm-Up How does the heart beat? What are the types of blood cells and their function? What is the function of the lymphatic system? List the pathway of one molecule of O2 from the air into your pinky toe What you need to know: • General characteristics of a respiratory surface • How O2 and CO2 are transported in blood • Pathway of O2 from airRBCtissues Respiration • Gas exchange supplies O2 for cellular respiration and disposes of CO2 • Partial pressure = pressure exerted by a particular gas in a mixture of gases • Gases always diffuse from higher partial pressure  lower partial pressure © 2011 Pearson Education, Inc • Respiratory media: O2 in air or water • Respiratory surface: body wall, skin, gills, tracheae, lungs • Characteristics: – Moist – Large surface area-to-volume ratio – Larger animals: associated with vascular system © 2011 Pearson Education, Inc Gills in aquatic animals Coelom Gills Parapodium (functions as gill) (a) Marine worm Gills Tube foot (b) Crayfish (c) Sea star Fish gills: absorb O2 through countercurrent exchange (blood flows opposite of water) Tracheal systems in insects Respiratory system in birds (lungs + air sacs) Mammalian respiratory system Pathway of O2 • • • • • • • Nose/mouth: filtered, warmed, humidified Pharynx Larynx: contains vocal cords Trachea: windpipe; lined with cartilage Bronchi: branches to lungs Bronchioles Alveoli: air sacs for gas exchange • Mucus: traps particles • Cilia: sweeps particles up to pharynx Alveoli Figure 42.30a Inhaled air Exhaled air Alveolar epithelial cells Alveolar spaces CO2 O2 Alveolar capillaries Pulmonary arteries Pulmonary veins Systemic veins Systemic arteries Heart CO2 O2 Systemic capillaries Body tissue (a) The path of respiratory gases in the circulatory system Diaphragm: dome-shaped muscle separating thoracic/abdominal cavities Control of Breathing in Humans • Control center = medulla oblongata • Responds to pH changes in blood • High CO2  carbonic acid forms  lowers pH • Sensors in the aorta and carotid arteries © 2011 Pearson Education, Inc Adaptations for gas exchange • Hemoglobin: respiratory pigment in vertebrates – subunits, each with heme group with iron (Fe) – Can carry molecules of O2 – Bohr shift: O2 dissociates from hemoglobin when blood pH is low • Arthropods, mollusks: – blue hemocyanin pigment – contains copper (Cu) © 2011 Pearson Education, Inc How CO2 is transported Bicarbonate ions (70%) Hemoglobin (23%) Dissolved in plasma (7%) © 2011 Pearson Education, Inc Respiratory Adaptations of Diving Mammals • Diving mammals have evolutionary adaptations that allow them to perform extraordinary feats – For example, Weddell seals in Antarctica can remain underwater for 20 minutes to an hour – For example, elephant seals can dive to 1,500 m and remain underwater for hours • High blood to body volume ratio • Stockpile O2 and deplete it slowly • Store oxygen in their muscles in myoglobin proteins © 2011 Pearson Education, Inc Respiratory Disorders • Asthma: airways constricted • Bronchitis: bronchi swollen and clogged • Pneumonia: inflammation of lung caused by infection • Tuberculosis (TB): infectious disease caused by M tuberculosis • Emphysema: lose elasticity of lung tissue • Lung Cancer: abnormal cell growth in lungs ... respiratory surface • How O2 and CO2 are transported in blood • Pathway of O2 from airRBCtissues Respiration • Gas exchange supplies O2 for cellular respiration and disposes of CO2 • Partial... for gas exchange • Mucus: traps particles • Cilia: sweeps particles up to pharynx Alveoli Figure 42.30a Inhaled air Exhaled air Alveolar epithelial cells Alveolar spaces CO2 O2 Alveolar capillaries... veins Systemic arteries Heart CO2 O2 Systemic capillaries Body tissue (a) The path of respiratory gases in the circulatory system Diaphragm: dome-shaped muscle separating thoracic/abdominal cavities