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BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor Chapter 42 Circulation and Gas Exchange Modules 22.1 – 22.4 From PowerPoint® Lectures for Biology: Concepts & Connections Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Respiration • Respiration controls the inhalation of oxygen and the exhalation of carbon dioxide • There are 3 phases of gas exchange: – 1. Breathing: oxygen enters the lungs and carbon dioxide is breathed out – 2. Oxygen is transported throughout the body by the heart and the blood (and CO2 is removed) – 3. Cells take up oxygen from the blood and send back CO2 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Gills • Gills are out-foldings of the body surface that are suspended in the water. • They are easy to keep moist, but the warmer the water the less oxygen is dissolved in it. • Blood flows in the opposite direction of water over the gills, this is called countercurrent exchange, and increases diffusion of oxygen. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Tracheal Systems • In insects, there are tiny air tubes that branch throughout the body. • This increases surface area for gas exchange. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Lungs • In humans and other mammals, air enters through the nose – It passes through the pharynx and larynx (voice box) into the trachea (windpipe) – The trachea forks to form two bronchi, one goes to each lung – Each bronchus branches into numerous bronchioles (smaller tubes) inside the lungs Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings • The human respiratory system Nasal cavity Pharynx (Esophagus) Left lung Larynx Trachea Right lung Bronchus Bronchiole Diaphragm (Heart) Figure 22.6A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings • The bronchioles end in clusters of tiny sacs called alveoli – Alveoli form the respiratory surface of the lungs – Oxygen diffuses through the thin walls of the alveoli into the blood Figure 22.6C Oxygen-rich blood Oxygen-poor blood Bronchiole Alveoli Blood capillaries Figure 22.6B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The diaphragm • The diaphragm, a sheet of skeletal muscle that forms the bottom of the rib cage, controls the volume of our lungs • We ventilate our lungs through negative pressure breathing, we suck air into our lungs (it’s pulled not pushed) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Chapter 23: Circulation • The function of the circulatory system is to transport oxygen throughout our body – It transports O2 and nutrients to cells – It takes away CO2 and other wastes Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Open vs. Closed • Humans have a closed circulatory system, all of our blood is in vessels • Insects have an open circulatory system, blood bathes all organs directly Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Heart Evolution • Fish have 2 chambered hearts • Amphibians and reptiles have 3 chambered hearts • Birds and mammals have 4 chambered hearts Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The Heart • The mammalian heart has two thin-walled atria that take in blood from the body • It also has thick-walled ventricles that pump blood to the body and lungs • In pictures, blue blood has NO oxygen, red blood has oxygen Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Pulmonary artery Aorta Superior vena cava Pulmonary artery LEFT ATRIUM RIGHT ATRIUM Pulmonary veins Pulmonary veins Semilunar valve Semilunar valve Atrioventricular valve Atrioventricular valve Inferior vena cava RIGHT VENTRICLE LEFT VENTRICLE Figure 23.4A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Arteries, Veins, Capillaries • Arteries carry oxygenated blood away from the heart and to the body • Veins carry deoxygenated blood from the body back to the heart and lungs to get oxygen • Capillaries are 1 cell thick to make diffusion easier Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Blood • Blood is made of: – Plasma – Red Blood Cells (Erythrocytes) – Platelets – White Blood Cells (Leukocytes) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Plasma • Plasma is mostly water and contains nutrients and minerals Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Red Blood Cells • Red blood cells contain hemoglobin – Hemoglobin enables the transport of O2 – They are produced in the bone marrow Figure 23.14 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings White Blood Cells • White blood cells (leukocytes) fight infections and cancer Basophil Eosinophil Monocyte Neutrophil Lymphocyte Figure 23.15 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Platelets • When a blood vessel is damaged or cut, platelets respond – They help trigger the formation of a clot that plugs the leak Figure 23.16B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings