Chapter 22 - Introduction SurvivinginThinAir A Review...

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Chapter 22 Lecture Outline Introduction Surviving in Thin Air A. Review: Cellular respiration: Animals need to obtain oxygen and glucose and rid themselves of waste carbon dioxide (Chapter 6; Figures 6.2, 6.3, and 6.6). B. Life at high altitude imposes many changes on the organs and tissues that function in respiration. 1. People born in and adapted to high altitudes have relatively large lungs and hearts, more red blood cells, and elevated hemoglobin concentrations. 2. A short period of conditioning will help those living in lower altitudes acclimate to higher altitudes. Faster heart rate and larger capillary diameter are replaced over time with deeper and more rapid rates of breathing, more capillaries, and higher numbers of red blood cells and levels of hemoglobin. 3. Many animals are capable of exchanging gases from environments humans would find inhospitable. Some birds can stand the cold and low oxygen concentrations of altitudes of 20,000–30,000 feet. They have more efficient lungs, hemoglobin with a very high affinity for oxygen, a larger number of capillaries, and muscle proteins that hold oxygen. C. Gas exchange (respiration) is the transposition of oxygen with CO 2 between an animal and its environment. I. Mechanisms of Gas Exchange Module 22.1 Overview: Gas exchange involves breathing, the transport of gases, and exchange of gases with tissue cells. A. The process of breathing (the intake of oxygen and removal of CO 2 ) makes it possible to use the nutrients obtained from digestion. There are three steps to gas exchange: 1. Breathing involves inhaling O 2 and exhaling CO 2 (Figure 22.1). 2. The transport of gases involves diffusion into and transport by hemoglobin in the red blood cells of the circulatory system. 3. Blood supplies every cell with O 2 and picks up waste CO 2 . B. There must be a constant supply of oxygen and removal of CO 2 at the cellular level. The process requires the combined efforts of the circulatory and respiratory systems. Module 22.2 Animals exchange O 2 and CO 2 across moist body surfaces. A. The portion of an animal where gas exchange with the environment takes place is called the respiratory surface. Respiratory surfaces vary among animal groups. However, what all respiratory surfaces have in common is that they must be moist, thin, and extensive. Gases must be dissolved in water before they can diffuse across a body surface. In each part of Figures 22.2A–D, the circle represents a cross section of the animal’s body in the region of the respiratory surface, and the yellow color represents the respiratory surfaces.
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B. Earthworms (Module 18.10) and other “skin breathers” must live in moist environments to keep their skin moist. Small size or flatness provides the high ratio of respiratory surface to body volume required for efficient gas exchange between environment and cells (Figure 22.2A). C.
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This note was uploaded on 03/10/2011 for the course BIOL 10 taught by Professor Kite during the Spring '11 term at Laney College.

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Chapter 22 - Introduction SurvivinginThinAir A Review...

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