Circulation and Gas Exchange Review

1. What purpose is served by the respiratory system? (get oxygen to cells and remove CO₂)

2. Why is the respiratory surface for terrestrial organisms inside rather than outside the body? (too muchwater loss)

3. How does the human respiratory system achieve a large surface area? (bronchioles and alveoli)

4. Explain the process of breathing. (diaphragm drops, chest cavity expands, pressure drops, air comes in;reverse for exhale)

5. How does the brain monitor the need for oxygen? (sensors in aorta and carotid arteries)

6. How is breathing rate set? (if CO₂ increase, need more oxygen, breathing rate increases)

7. How is oxygen carried in the blood? (bound to hemoglobin)

8. What are the cause and symptoms of anemia? (lack of iron; fatigue)

9. Outline the effects of smoking on the respiratory system. (damage to cilia, emphysema)

10. Why do large, multicellular animals require a circulatory system? (diffusion too slow to reach allcells)

11. Distinguish between systemic and pulmonary circulation. (systemic - body; pulmonary - lungs)

12. Describe the differences between arteries and veins. (arteries - away; veins - toward)

13. Describe capillaries. (very tiny, thin walled, reach all cells)

14. What function do capillaries serve? (exchange of materials)

15. What causes a pulse? (expansion of artery as blood surges)

16. What is an aneurysm? (weakening of artery wall results in bulging out) Why are they dangerous? (artery can rupture - internal bleeding)

17. What is the function of the pulmonary and aortic semilunar valves? (keep blood from flowing backinto the ventricles)

18. Blood pressure in veins is much lower than that in arteries. Explain how this is overcome to ensure blood is returned to the heart. (veins squeezed by skeletal muscle, one-way valves)

19. It is not unheard of for soldiers to faint while standing at attention for a long period of time. Explain. (without skeletal muscle movement, blood would pool in legs)

20. Using examples, explain the purpose served by vasoconstriction and vasodilation. (direct blood flow;blushing, white)

21. You visit the doctor and have your blood pressure measured. It is 150/110. Is this high? (yes) Why might the doctor be more concerned with diastolic pressure than with your systolic pressure. (diastolic isduring ventricular relaxation so a higher pressure is more concerning)

22. What is the function of the pacemaker and why is it necessary? (generates electrical impulses thatcause heart muscle to contract. Needed to coordinate contraction of heart muscle cells)

23. How can the basic heart rate set by the pacemaker be modified? (brain can over-ride)

24. What are the two basic causes of heart attacks? (fatigue or blocked coronary arteries)

25. What is a coronary bypass operation and why would one be performed? (bypass blocked coronaryartery)

26. Explain why the ventricles have thicker walls than the atria. (ventricles pump blood further)

27. Why does the left ventricle have thicker walls than the right? (left pumps to body, right to lungs)

28. What is the only artery in the body that carries deoxygenated blood? (pulmonary artery)

29. Why is this artery an exception? (carrying blood to lungs)

30. Describe the disease atherosclerosis and explain how it can result in high blood pressure. (narrowingof the arteries so heart must pump faster and harder to get same volume through)

31. What is the relationship between diet and heart disease? (high cholesterol, high saturated fats, highsalt)

32. What is the adaptive value of the fact that arteries are usually located far below the surface of the skin? (blood at higher pressure would bleed faster, therefore they are protected deep under skin)

33. Occasionally, a child is born with an opening in the wall between the right and left ventricles. Explain how such a defect might affect the child? (mixing of blood, lack of energy)

34. Explain how starvation conditions can lead to edema. (plasma proteins used so less osmotic pressureso more fluid in tissues)

35. Imagine that you are a doctor and that you have diagnosed one of your patients as having high blood pressure. You prescribe a low salt diet. Why? (salt increases osmotic pressure of blood so water retainedin blood causing high blood pressure)

36. Imagine now that you became bored with the mundane life of a family physician and decided to become an Emergency Medicine Technician. At the scene of a car accident, a victim has lost a great deal of blood and is going into shock. The symptoms you observe are weak and rapid pulse, and falling body temperature. Explain. (loss of blood volume leads to weak pulse, heart rate tries to compensate for lessblood so rapid pulse, blood loss contributes to lower temperature)

37. Define cardiac output, stroke volume, and heart rate. (amount pumped each minute; amount pumpedper beat; beats per minute)

38. Describe the features of RBC. (biconcave disks, no nucleus, 120 d lifespan)

39. What are the differences between RBC and WBC? (RBC carry O₂, WBC immune system)

40. What is the function of platelets? (clotting)