Chapter 42 Notes (Circulation and Gas Exchange)

Chapter 42 Notes (Circulation and Gas Exchange) - Chapter...

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1. The Survey of different types of circulation a. Primitive levels of organisms (Sponges, Cnidarians, Flatworms…) – simple diffusion through the simple wall. b. After primitive levels of organisms, the organisms have either closed circulatory system or open circulatory system. i. Open circulatory system: The fluid of the body (hemolymph) is ductless. Gas exchange does not occur through the fluid. Advantage – low pressure (therefore saves energy in the body.), no capillaries (easy circulation, therefore). Examples) Arthropods (Insects), Mollusca… ii. Closed circulatory system: The fluid of the body (blood) is in the duct. Gas exchange occurs through the fluid – hemoglobin. Advantage - quick rate of gas exchange since the pressure is high. Examples) Amphibians, Annelids, mammals, Mollusk (Squid, octopus) … c. Heart was developed as time went on (evolution.) i. Heart consists of atrium and ventricle. Atrium – the part that receives the blood. Ventricle – the part that sends the blood. ii. Diversity of Heart Structure Fish: 1 atrium + 1 ventricles – 2 chambers Amphibian: 2 atria + 1 ventricle – 3 chambers Reptiles: 2 atrium + 2 ventricles (But, no separation) – 4 chambers - Oxygenated blood can be mixed with non-oxygenated blood. Mammals, Birds: 2 atrium + 2 ventricles (But, separation) – 4 chambers - The separation of oxygenated blood from non-oxygenated blood – much more effective. 2. Mammalian Heart a. The whole pathway for the heart (RED for oxygen-rich / BLUE for oxygen-poor) Right Atrium → Right Ventricle → Pulmonary Artery → Lu ngs Anterior/Posterior Vena Cava ← Bo dy ← Aorta ← Left Ventricle ← Left Atrium ← Pulmonary Vein b. i. Left ventricle - highest blood pressure ii. Vena cava - lowest blood pressure c. Valves – the thin layer which makes the blood not flow back.
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i. 4 valves exist in the mammalian heart ii. AV valves: Between ventricles and atrium iii. SA valves: Between ventricles and arteries d. Two different types of circulation i. Systemic circulation: The circulation which carries oxygenated blood away from the heart to the body, and returns deoxygenated blood back to the heart. ii. Pulmonary circulation: The circulation which carries oxygen-depleted blood away from the heart, to the lungs, and returns oxygenated blood back to the heart. 3.
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This note was uploaded on 02/11/2012 for the course ZOOLOGY 152 taught by Professor Stephengammie during the Fall '11 term at Wisconsin.

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Chapter 42 Notes (Circulation and Gas Exchange) - Chapter...

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