Chapter 23

Blood pressure is highest in _______ , and blood moves most slowly in ________. a. veins; capillaries b. arteries; capillaries c. veins; arteries d. arteries; veins

Which of the following is the main difference between your cardiovascular system and that of a fish? a. Your heart has two chambers; a fish heart has four. b. Your circulation has two circuits; fish circulation has one. c. Your heart chambers are called atria and ventricles. d. Yours is a closed system; the fish's is an open system.

Paul's blood pressure is 150/90. The 150 indicates _______ ,and the 90 indicates _______. a. pressure in the left ventricle; pressure in the right ventricle b. pressure during ventricular contraction; pressure during heart relaxation c. systemic circuit pressure; pulmonary circuit pressure d. pressure in the arteries; pressure in the veins

Which of the following initiates the process of blood clotting? a. damage to the lining of a blood vessel b. conversion of fibrinogen to fibrin c. attraction of white blood cells to a site of infection d. conversion of fibrin to fibrinogen

Blood flows more slowly in the arterioles than in the artery that supplies them because the arterioles a. have thoroughfare channels to venules that are often closed off, slowing the flow of blood. b. have sphincters that restrict flow to capillary beds. c. are narrower than the artery. d. collectively have a larger cross-sectional area than does the artery

Which of the following is not a true statement about open and closed circulatory systems? a. Both systems have some sort of a heart that pumps a circulatory fluid through the body. b. A frog has an open circulatory system; other vertebrates have closed circulatory systems. c. The blood and interstitial fluid are separate in a closed system but are indistinguishable in an open system. d . Some of the circulation of blood in both systems results from body movements.

Trace the path of blood starting in a pulmonary vein, through the heart, and around the body, returning to the pulmonary vein. Name, in order, the heart chambers and types of vessels through which the blood passes.

If blood were supplied to all of the body's capillaries at one time, a. blood pressure would fall dramatically. b. resistance to blood flow would increase. c. blood would move too rapidly through the capillaries. d. the amount of blood returning to the heart would increase.

Explain how the structure of capillaries relates to their function of exchanging substances with the surrounding interstitial fluid. Describe how that exchange occurs.

Some babies are born with a small hole in the wall between the left and right ventricles. How might this affect the oxygen content of the blood pumped out of the heart into the systemic circuit?

Juan has a disease in which damaged kidneys allow some of his normal plasma proteins to be removed from the blood. How might this condition affect the osmotic pressure of blood in capillaries, compared with that of the surrounding interstitial fluid? One of the symptoms of this kidney malfunction is an accumulation of excess interstitial fluid, which causes Juan's arms and legs to swell. Can you explain why this occurs?

Physiologists speculate about cardiovascular adaptations in dinosaurs-some of which had necks almost 10 m (33 feet) long. Such animals would have required a systolic pressure of nearly 760 mm Hg to pump blood to the brain when the head was fully raised. Some analyses suggest that dinosaurs' hearts were not powerful enough to generate such pressures, leading to the speculation that long-necked dinosaurs fed close to the ground rather than raising their heads to feed on high foliage. Scientists also debate whether dinosaurs had a "reptile-like" or "bird-like" heart. Most modern reptiles have a three- chambered heart with just one ventricle. Birds, which evolved from a lineage of dinosaurs, have a four-chambered heart. Some scientists believe that the circulatory needs of these long-necked dinosaurs provide evidence that dinosaurs must have had a four-chambered heart. Why might they conclude this?