Chapter 42 Free Response Questions

1. Diagram the anatomy of the human heart (use fig 42.5 as a guide in your diagram). Label all the parts that are labeled in Figure 42.5. Diagram how the blood flows through the heart and the entire cardiovascular system (see fig 42.4)- be sure to label the different parts of the system as is done in fig 42.4. Describe where in the system the blood is low in oxygen and where it is high in oxygen. What is the function of the valves in the heart? How do the atrioventricular valves differ from the semilunar valves? What causes the sound of the beating heart? Describe what is meant by “double circulation.” What are the names of the two circulation systems called? Why do mammals need a system like this compared to amphibians and fish (see text on page 814 , esp the second column and fig 42.3)?

2. Describe what blood pressure is and the two things that determine it (page 818-819; see top of pg. 819, second column in particular). Describe how these two things work, individually, to create blood pressure. Describe two ways blood pressure can be increased and two ways it can be decreased (describe the actual physical process based on your previous answer, an answer like, “To be put in a stressful situation” is not a sufficient answer). According to your lab does your blood pressure increase, decrease, or stay the same if you suddenly stand up from a reclining position? Why does this happen?

3. Explain how breathing is controlled. Which two regions in the brain are responsible for the control of breathing? Explain how the negative feedback system works which prevents our lungs from overextending when we take a breath. Explain in detail how the medulla monitors carbon dioxide concentration in the blood to maintain homeostatic control of respiration; be sure to discuss how the production of carbonic acid and a change in pH function in this feedback system. Since the control of respiration is not influenced by the oxygen concentration in the blood how are people able to increase their breathing rate in a low oxygen environment? (see page 833 & figure 42.25)