19. The Blood Vessels

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

Hormones that decrease blood volume and blood pressure include antidiuretic hormone and aldosterone.

Explain the reasons for the observed changes in blood flow velocity in the different regions of the circulation.

Capillary permeability increase and plasma proteins leak into the interstitial fluid as part of the inflammatory process. Why is this desirable?

The Agawam High School band is playing some lively marches while the coaches are giving pep talks to their respective football squads. Although it is September, it is unseasonably hot (88°F/31°C) and the band uniforms are wool. Suddenly Ryan, the tuba player, becomes light-headed and faints. Explain his fainting in terms of vascular events.

Compare the effects of the cardioacceleratory and cardioinhibitory centers on cardiac output and blood pressure.

Which of the following is greater?

(a) The osmotic pressure of the interstitial fluid during inflammation

(b) The osmotic pressure of the interstitial fluid during normal conditions

(c) Neither is greater

When we are cold or the external temperature is low, most venous blood returning from the distal part of the arm travels in the deep veins where it picks up heat (by countercurrent exchange) from the nearby brachial artery en route. However, when we are hot, and especially during exercise, venous return from the distal arm travels in the superficial veins and those veins tend to bulge superficially in a person who is working out. Explain why venous return takes a different route in the second situation.

Edema is a common clinical problem. On your first day of a clinical rotation, you encounter four patients who have edema for different reasons. Your challenge is to explain the edema in terms of either an increase or a decrease in one of the four pressures that causes bulk flow.

(1) First you encounter Mrs. Taylor in the medical unit awaiting a liver transplant. What is the connection between liver failure and her edema?

(2) Next in the obstetric ward, Mrs. So is experiencing premature labor and has edema in her legs. Which bulk flow pressures might be altered here?

(3) In emergency, Mr. Herrera is in anaphylactic shock. His capillaries have become leaky, allowing plasma proteins that are normally kept inside the blood vessels to escape into the interstitial fluid. Which of the bulk flow pressures is altered in this case and in what direction is the change?

(4) Finally, in oncology Mrs. O'Leary is recovering from breast cancer surgery. Her right breast and all of her axillary lymph nodes were removed. Unfortunately, this severed most of the lymphatic vessels draining her right arm. You notice that this arm is quite edematous. Why? Mrs. O'Leary is given a compression sleeve to wear on this arm to help relieve the edema. Which of the bulk flow pressures will be altered by the compression sleeve?

Arteries tend to have thicker walls than veins. Which of the following is a reason for this?

Which of the following physiological changes would likely occur in someone’s blood vessels when they begin an intense exercise session?

Net hydrostatic pressure forces water ____ a capillary; net osmotic pressure reabsorbs water _____ a capillary.

(a) into, out of

(b) out of, into

(c) out of, out of

(d) into, into