Anatomy & Physiology II
Chapter 20
The Circulatory System
1. At any given moment, most of the body's blood is in:
a. The veins
d. The capillaries
b. The
arteries
e. The lungs
c. The heart
2. Water enters the blood capillaries by means of _?_.
a. Filtration
d. Pinocytosis
b.
Active transport
e. Facilitated diffusion
c.
Osmosis
3. Inadequate pumping activity of the heart is likely to cause:
a. Neurogenic shock
d. Cardiogenic shock
b.
Venous pooling shock
e. Anaphylactic shock
c.
Obstructed venous return shock
4. Positive feedback is most important in:
a. Transient ischemic attack
d. The medullary ischemic reflex
b.
Compensated shock
e. The baroreflex
c.
Decompensated shock
5. The net filtration pressure of a blood capillary is the difference between:
a. Colloid osmotic pressure and oncotic pressure
b.
Blood hydrostatic pressure and interstital hydrostatic pressure
c.
Blood pressures at arterial and venous ends
d.
Net hydrostatic pressure and oncotic pressure
e.
Interstitial pressure and oncotic pressure
6. In autoregulation, all of the following chemicals tend to increse blood flow except:
a. Nitric oxide
d. Histamine
b. Carbon
dioxide
e. Lactic acid
c.
Thromboxane
7. Identify the net filtration pressure in a capillary under the following conditions:
Interstitial hydrostatic pressure = -2 mmHg
Colloid osmotic
pressure (COP) of tissue fluid = 6 mmHg
Colloid osmotic
pressure of the blood = 29 mmHg
Blood hydrostatic
pressure = 32 mmHg
a. 1 mmHg
d. 11 mmHg
b. 5 mmHg
e. 65 mmHg
c. 8 mmHg
8. Using the same values listed in #7, determine the oncotic pressure.
a. -2 mmHg
d. 34 mmHg
b.
23 mmHg
e. 35 mmHg
c. 30 mmHg
9. In which of the following organs would you find fenestrated capillaries?
a. Kidneys
d. Endocrine glands
b. Brain
e. Bone marrow
c. Lungs
10. The elastic arteries absorb part of the energy provided by ventricular systole and then return it via recoil during ventricular diastole to provide continuous blood flow.
11. Veins are called capacitance vessels because they hold a large amount of blood.
12. Blood flow is inversely proportional to the radius4 of the blood vessel. ( F = 1/r4) If we decrease the radius of a vessel by one half, how much will we change the velocity of flow? Will blood flow increase or decrease? (1/2)4 = 1/16 Velocity of blood flow will decrease by 16x
13. What are sinusoids? What is their function? Sinusoids are large, irregular blood-filled spaces with modifications such as fenestrations, few tight junctions, and large intercellular clefts to allow for passage of large molecules and blood cells. Blood flow in sinusoids is extremely sluggish and allows for modification of blood. For example, in liver sinusoids, liver cells absorb nutrients and destroy bacteria . Also, newly formed plasma proteins, clotting factors, and blood cells enter the circulation through sinusoids.
14. Briefly describe reactive hyperemia. Be sure to include what types of autoregulatory control are involved. Following temporary loss of blood flow, a tissue will experience a dramatic increase in blood flow due to both the myogenic response of autoregulation, and the metabolic response to accumulating wastes and depleted oxygen.
15. Identify three vasoactive chemicals secreted by platelets, endothelial cells, or perivascular tissues. For each chemical identified include its source, and its effect on vasomotion.
Many possible answers - see Powerpoints and text
Serotonin, prostacyclin, nitric oxide, endothelins, bradykinins, histamine, prostaglandins, etc.
16. Compare angiogenesis and anastamoses. How are they different? How are they alike?
17. Briefly describe three neural reflexes used to control blood pressure. Be sure to include the types of receptors and effectors involved in each, and the effects of each.
18. Briefly describe three hormonal mechanisms used to control of blood pressure. Be sure to include the source of each hormone, and the specific effects.
19. Identify 5 factors that contribute to venous return. What is the effect of exercise on each of these factors?
20. Anaphylactic shock has elements of both hypovolemic shock and vascular shock. Explain.
21. Why does isometric contraction of skeletal muscle cause fatigue much more rapidly than intermittent isotonic contractions of the same muscle?