1. Circulation and gas exchange Salmon gill

2. Life exists in a friendly, watery medium What are the needs of the cell? What is the fluid that supplies the needs of the cell? What are its characteristics? What keeps that fluid “friendly?”

3. Overview of circulatory systems Three (or four) components: –Fluid bathing cells = interstitial fluid –Circulatory fluid = “hemolymph” or “blood” –Tubes = blood vessels –Muscular pump = heart (usually) Pressure produced by the heart moves blood through vessels down a pressure gradient, and the blood eventually returns to the heart Two types of circulatory systems –Open –Closed

4. Open circulatory system Arthropods and mollusks Blood and interstitial fluid are not separated; they form hemolymph Hemolymph pumped through sinuses (spaces around organs) and returned via pores, or ostia Fig. 42.3a

5. Closed circulatory system Blood and interstitial fluid are separated Earthworms, squid, octopus, and vertebrates All exchange between blood and tissues happens by diffusion in capillary beds. Fig. 42.3b

6. A few more terms Cardiovascular system of vertebrates Hearts are composed of atria (chambers that receive blood) and ventricles (chambers that pump blood out) Arteries contain blood moving away from the heart and towards capillaries Veins contain blood moving towards the heart and away from capillaries Sinuses are spaces where blood collects But the thin-walled capillaries are still where all the real action is.

7. Circulation in vertebrates Exchanging oxygen and carbon dioxide PICK UP OXYGEN LET OXYGEN GO 2 chambers Single circulation

8. Single Circulation Allows only Low Pressure Circulation to the tissues PICK UP OXYGEN LET OXYGEN GO 2 chambers

9. PICK UP OXYGEN LET OXYGEN GO 2 chambers 3 chambers Single circulation; Loses pressure Double circulation; Maintains pressure

10. Three chambered hearts and dual circulation maintain pressure but allow mixing PICK UP OXYGEN LET OXYGEN GO 2 chambers 3 chambers Single circulation; Loses pressure Double circulation; Maintains pressure O 2 mixing?

11. Dual circulation with a 4-chambered heart: high pressure, no mixing: most efficient PICK UP OXYGEN LET OXYGEN GO 2 chambers 3 chambers4 chambers Single circulation; Loses pressure Double circulation; Maintains pressure O 2 mixing?

12. Mammalian cardiovascular system Double circulation Right: deoxy Left: oxy Fig. 42.6

13. Mammalian heart Wall thickness Valves: AV & semilunar Lub-dup = valves closing A heart murmur is a defect in a valve Fig. 42.7

14. Where were we? Animal Physiology –Circulatory System –Respiratory System

15. Needs of the cell - friendly, watery medium Structure of circulatory systems –Interstitial fluid –Circulating fluid –Pumping organ –Blood vessels and spaces Functions –Transport (of nutrients, oxygen, wastes). The role of respiratory pigments. –Defense Types of circulatory systems –None –Open –Closed Circulation in vertebrates –Types of circuit Single Double/three chambered heart Double/four chambererd heart Blood pressure

16. Blood flow Systole vs. diastole Fig. 42.10

17. Arteries and veins Which is which?

18. Blood vessels 1 to 3 layers Endothelium: layer of smooth, flattened cells Fig. 42.8 Elastic Thicker Thinner Elastic

19. Blood Specialized connective tissue Fig. 42.14 Hemoglobin

20. Cardiovascular disease Heart attacks—death of cardiac muscle due to prolonged blockage of coronary arteries (which bring oxygenated blood to heart) Strokes—death of nervous tissue in the brain due to blockage or rupture of arteries in head Atherosclerosis—chronic condition often leading to the above conditions; plaques (fibrous connective tissue + lipids) narrow arteries Normal Plaque

21. Gas exchange Tracheal systems Gills Lungs Fig. 42.18 DIFFUSION

22. Tracheal systems Life on land

23. Skin Moist skin - small aquatic invertebrates, salamanders, frogs

24. Skin and External Gills mudpuppy tadpole

25. Internal Gills Water vs. air –4 – 8 vs. 210 ml O 2 per liter –Diffusion speed –Continuously pumping water

26. Countercurrent exchange Always maintaining a gradient Fig. 42.21

27. Why do fish out of water suffocate?

28. Lungs Life on land Fig. 42.23 Note [0 2 ] & veins & arteries

30. phagocytosis

32. Gas loading and unloading Partial pressures and diffusion