17. The Blood

How many heme groups are required to synthesize 4 hemoglobin molecules?

Why is it important for erythrocytes to have a high surface area to volume ratio?

Cynthia lives in Miami, a city at low altitude. She goes on a month-long trip to the Andes Mountain range (at high altitude) where the air pressure is lower and therefore there is less oxygen in each breath she takes. Upon returning to Miami, how might a sample of her blood differ from a sample taken before she left for her trip?

Anemia is a blood disorder where the $O_2$-carrying capacity of blood is too low to support the body's tissues. Which of the following is not a possible cause of anemia?

Dehydration would:

(a) Cause an increase in the hematocrit

(b) Cause a decrease in the hematocrit

(c) Have no effect on the hematocrit

(d) Cause an increase in plasma volume

Anemia is defined as:

a. A decreased oxygen-carrying capacity of the blood.

b. A decreased iron content of the blood.

c. Decreased bone marrow function.

d. Abnormalities in hemoglobin.

Predict how abnormal hemoglobin proteins that contain only two iron ions, instead of four, would affect homeostasis.

Mr. Jackson presents to the emergency room with a minor wound that has bled for several days. An examination of his medical history reveals that Mr. Jackson has hemophilia A, which is caused by a deficiency of factor VIII. Your co-worker suggests that you give Mr. Jackson some platelets to stop the bleeding. Will this help your patient? Why or why not?

Alan Forsythe, a middle-aged college professor from Boston, is in the Swiss Alps studying astronomy during his sabbatical leave. He has been there for two days and plans to stay the entire year. However, he notices that he is short of breath when he walks up steps and tires easily with any physical activity. His symptoms gradually disappear, and he feels fine after less than a month. Upon returning to the United States, he has a complete physical exam and is told that his erythrocyte count is higher than normal.

a. Attempt to explain this finding.

b. Will his RBC count remain at this higher-than-normal level? Why or why not?