Final Exam Lecture Notes

Final Exam Lecture Notes - Chapter 42 Circulation and Gas...

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Chapter 42: Circulation and Gas Exchange Concept 42.1: Circulatory systems link exchange surfaces with cells throughout the body Transport systems functionally connect the organs of exchange with the body cells Gastrovascular Cavities Simple animals like cnidarians have a body wall only 2 cell layers thick btw external environment and gastrovascular cavity Gastrovascular cavity functions both in digestion and circulation o single opening maintains continuity between the fluid inside the cavity and the water outside Figure 42.2 More Complex Animals Have Two Types of Circulatory Systems Open circulatory system: blood bathes the organs directly o Circulatory fluid = the Interstitial fluid o Ex/ anthropods, most mollusks Closed circulatory system: blood is confined to vessels and is distinct from the interstitial fluid
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o Circulates blood ENTIRELY within VESSELS o Ex/some invertebrates and all vertebrates Figure 42.3 Circulatory System Parts Both of these types of systems have three basic components o 1. Blood= A circulatory fluid (blood) o 2. Blood Vessels= A set of tubes (blood vessels) o 3. Heart= A muscular pump (the heart) Atria= chambers receive blood entering heart Ventricles= chambers carry blood out Vertebrate Circulatory System Closed circulatory system of humans and other vertebrates is called the: Cardiovascular system: closed circulatory system with a heart and branching network of arteries, capillaries, and veins.
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o Arteries: vessels carry blood away from the heart to organs throughout the body HEART-- ORGANS Branch into arterioles= small vessels that convey blood to the capillaries o Capillaries: microscopic vessels with very thin, porous walls that penetrates the tissues and consists of a single layer of endothelial cells that allows exchange between the blood and interstitial fluid Networks called capillary beds At the “downstream” end, capillaries converge into venules, which then converge into veins Heart Arteries Arterioles Capillaries Venules Veins o Veins: vessels that carry blood back to the heart ORGANS HEART Figure 42.4 and 42.5 Single Circulation vs. Double Circulation o Single Circulation: blood passes through the heart once in each complete circuit In bony fishes, rays, and sharks Consists of 2 chambers: atrium and ventricle o Double Circulation: a circulatory system consisting of separate pulmonary and systematic circuits, in which blood passes through the heart after completing each circuit Pulmonary circuit = supplies blood to the lungs Right side of the heart 1 st part of circulation
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Systematic circuit= supplies all body organs except those involved in gas exchange Left side of the heart Completes the circulation **Double circulation provides a vigorous flow of blood to the brain, muscles, and other organs bc the heart repressurizes the blood destined for these tissues after it passes through the capillary beds of the lungs or skin**
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This note was uploaded on 09/12/2011 for the course BIOL 1201 taught by Professor Wishtichusen during the Fall '07 term at LSU.

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Final Exam Lecture Notes - Chapter 42 Circulation and Gas...

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