1. Athletes who abuse erythropoietin have many more red blood cellsthan usual.

a. Explain why anathlete might die from having too many red blood cells
b. Why is death morelikely at night when an athlete is sleeping, rather than during theday when he or she is active? Base your explanation on the heartrate.

2. After a trip to acountry close to the equator, a student returns covered withmosquito bites. She has a low fever for a week, and blood testsshow a very high level of eosinophils. Can you think of a diseasethat might cause these symptoms? Base your answer on what you knowabout tropical diseases.

3. Considering what youhave learn from the "homeostasis" section of this chapter, youshould be able to think of at lease two other organ systems thatinteract with the cardiovascular system (and the blood inparticular) to regulate blood oxygen.

4. List two organ systems and describehow they work with the cardiovascular system to make oxygenavailable to body cells.