1. In autoregulation of systemic arterioles, all of the following tend to increase blood flow except
  1. high O2
  2. high carbon dioxide
  3. low pH
  4. adenosine
  5. lactic acid
  1. Blood solutes can pass through the walls of capillaries by passing through either the endothelial cell, the intercellular clefts, or
  1. the thoroughfare channels.
  2. the tight junctions
  3. the epithelial cells.
  4. the sinusoids.
  5. the fenestrations.
  1. All of the following pressures, except ___ , are in favor of filtration through capillary wall.
  1. capillary blood hydrostatic pressure
  2. plasma colloid osmotic pressure
  3. a negative interstitial hydrostatic pressure
  4. interstitial colloid osmotic pressure
  5. interstitial oncotic pressure
  1. According to Poiseuille's law, blood flow will decrease if
  1. vessel radius decreases.
  2. viscosity decreases.
  3.  increases.
  4. pressure increases.
  5. blood vessel length decreases.
  1. If a person's arterial blood pressure measures 130/85, the mean arterial blood pressure is
  1. 85 mmHg.
  2. 100 mmHg.
  3. 107.5 mmHg.
  4. 128.3 mmHg.
  5. 130 mmHg.
  1. The following sites, except ___, are under strict neural and hormonal regulations to control blood flow into an individual capillary network.
  1. the small arteries
  2. the muscular arteries
  3. the veins
  4. the precapillary sphincters
  5. the arterioles.

47. Which of the following is incorrect?

  1. Blood cannot flow from an artery into a vein without passing through any capillary network.
  2. Blood can flow from an artery through only one capillary network into a vein.
  3. Blood can flow from an artery, through two capillary networks, into a vein.
  4. Blood cannot flow from a vein into an artery without passing through the heart.
  5. Blood can flow from a vein into a capillary network.

48. A delay of electrical signals at AV node has its physiological significance of allowing

  1. more blood to fill in ventricles during atrial contraction.
  2. longer relaxation of atria.
  3. faster conduction inside ventricles.
  4. SA node to rest for a longer time.
  5. AV valves to open more quickly.

49. Mean arterial blood pressure is maintained in a normal range by means of all of the following except

  1. baroreceptor-initiated flexes.
  2. chemoreceptor-initiated reflexes.
  3. renin-angiotensin system.
  4. arterial autoregulation.
  5. vasopressin or antidiuretic hormone (ADH).

50. When mean arterial blood pressure drops, blood supply to the brain and the coronary circulation is better maintained than any other peripheral organs such as kidneys, intestines, and skeletal muscles because

  1. the carotid arteries and coronary arteries are closer to aorta.
  2. the arterioles in the brain and coronary arteries are not as reactive to neural and hormonal regulations as those in the peripheral organs.
  3. diameters of the carotid arteries and coronary arteries are larger.
  4. the carotid arteries and coronary arteries are less affected by gravity.
  5. blood vessels in the peripheral organs are less affected by neural and hormonal regulations.