Biology, 6th Edition

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Greg Steinberg AP Biology Chapter 42 Circulation and Gas Exchange A. Circulation in Animals a. Transport Systems i. Transport Systems connect organs of exchange with body cells ii. Diffusion can not transport everything needed by cells. iii. The circulatory systems makes it so no substance needs to diffuse far to get to a cell. iv. Blood carries oxygen to all parts of the body – it is powered by the heart. v. Gas and Fluid movement functions as two systems, circulatory and respiratory. b. Gastrovascular Cavities i. Body plans of some organisms make a circulatory system not needed. ii. The outer cells are in the fluid, able to take in needed nutrients. The nutrients can then diffuse to the other cells. c. Open and Closed Circulatory Systems i. Both have blood, blood vessels, and a heart. ii. The heart pumps the blood through the blood vessels that carry the needed nutrients, the expended blood then returns to the heart. iii. Open Circulatory Systems – The heart pumps the hemolymph (blood and interstitial fluid) through the body. iv. Closed Circulatory Systems – Blood is separated and travels in the vessels of an organism. Blood vessels branch into smaller ones, delivering blood to all the organs. d. Cardiovascular Adaptations i. The heart can have 1-2 atria, and 1-2 ventricles. ii. Arteries, Veins, and Capillaries are the main blood vessels in the circulatory system. iii. Arteries carry blood away from the heart ad branch into very small capillaries with thin porous walls. iv. Capillaries are organized into networks called capillary beds. v. Diffusion exchanges gasses and nutrients across the wall. vi. Capillaries then converge into venules, which converge into veins, which carry used blood back into the heart. vii. A higher metabolic rate usually means a more complex circulatory system. viii. Gill circulation is pumped by a two chambered heart across the gills that pick up oxygen and deposit CO2, which then is pumped to the systematic capillaries that give oxygen to the organs.
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ix. Systemic Circuits allow for the blood to be pumped through only 1 capillary bed before returning to the heart to keep blood pressure. x. Double Circulation returns the oxygen poor blood to return to the atrium to regain oxygen before being pumped through the system again. xi. Double circulation allows the system to pump only oxygen rich blood to organs, and keeps oxygen poor blood separate. e. Double Circulation steps i. The right ventricle pumps blood to the lungs. ii. The pulmonary arteries carry the blood to the lungs. iii. The capillary beds deposit CO2 and gain Oxygen iv. The blood returns to the left atrium of the heart v. The left ventricle pumps the blood into the Aorta. vi.
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bio42 - Greg Steinberg AP Biology Chapter 42 Circulation...

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