Jennifer has the "stomach flu" that is going around campus and has been vomiting profusely for the past 24 hours. Not only has she been unable to keep down fluids or food but she has also lost the acidic digestive juices secreted by the stomach that are normally reabsorbed back into the blood farther down the digestive tract. In what ways might this condition threaten to disrupt homeostasis in Jennifer's internal environment? That is, what homeostatically maintained factors are moved away from normal by her profuse vomiting what body systems respond to resist these changes.

1. Considering the nature of negative-feedback control and the function of the respiratory system, what effect do you predict that a decrease in CO2 in the internal environment would have on how rapidly and deeply a person breathes?

2. Given that most AIDS victims die from overwhelming infections or rare types of cancer, what body system do you think HIV (the AIDS virus) impairs?

3. Body temperature is homeostatic ally regulated around a set point. Given your knowledge of negative feedback and homeostatic control system, predict whether narrowing or widening of the blood vessels of the skin will occur when a person exercises strenuously.

4. A 37-year old woman is admitted to the hospital after complaining of chest pains. She admits to having had severe headaches for several days prior to seeking medical help. She is also taking medications for high blood pressure and is four months pregnant. Which medical imaging procedures listed in your text would be the best choice of a physician attempting to determine her condition? (Assume all equipment is available and there are unlimited funds to cover costs incurred.)