Exam 5, Unit 4 Guyton Review Questions
35. What substance in the plasma is the major factor that contributes to plasma colloid osmotic pressure?
Albumin because it does not pass through the capillary walls and exerts osmotic pressure. The capillary wall is highly permeable to sodium chloride, glucose, cholesterol, potassium
63. A decrease in which of the following would be expected to occur in response to an increase in sodium intake? Angiotensin II, nitric oxide, sodium excretion, atrial natriuretic peptide
Angiotensin II
62. Excess production of which of the following would most likely result in chronic hypertension? Atrial natriuretic peptide, prostacyclin, angiotensin II, nitric oxide
Angiotensin II...... is a powerful vasoconstrictor antinatriuretic, and hypertensive hormone. Nitric oxide and prostacyclin are potent vasodilator's and natriuretic substances. Atrial natriuretic peptide is a natriuretic (natural diuretic) and antihypertensive.
26. Blood flow through a vessel is 100 mL/min. What would be the approximate flow through the vessel after increasing the vessel diameter to four times normal assuming that the pressure gradient was maintained?
Answer: 25,600 ML/min According to a scientific law flow through the vessel increases in proportion to the fourth power of the radius. A fourfold increase in vessel diameter or radius would increase four to the fourth power, or 256 times normal. Rule: R ^ 4 if R = 1, take 4×1 = 4 4 ^ 4 = 25,600 Or rule: blood flow rate (100 ML/min) ×256 = 25,600
16. A diameter of a precapillary arteriole is increased in a muscular vascular bed. A decrease would happen where?
Arteriolar resistance The decrease in arterial arteriolar resistance would lead to an increase in vascular conductance and capillary blood flow, hydrostatic pressure, and filtration rate.
2. A 25-year-old guy exercises. How does this affect arteriolar resistance, adenosine concentration, vascular conductance in skeletal muscles?
Decrease arteriolar resistance due to release of vasodilator substances like adenosine (increase). The increase in tissue adenosine concentration decreases arteriolar resistance and increases vascular conductance in blood flow to the skeletal muscles.
47. A decrease in what 2 pressures would tend to increase lymph flow?
Decrease in interstitial hydrostatic pressure, decrease in plasma colloid osmotic pressure
54. If Blood flow stays the same and pressure decreased, what would happen to resistance? Hint: V= IR, R = V/I
Decreased vascular resistance
24. How does hyperaldosteronism hypertension effect extracellular fluid volume, plasma renin activity, plasma potassium concentration?
ECF increase, plasma renin activity decrease, plasma potassium concentration decrease. Excess secretion of aldosterone results in enhanced tubular reabsorption of sodium and secretion of potassium. The increased reabsorption of sodium and water leads to an increase in extracellular fluid volume, which in turn suppresses renin release by the kidney. Increase in potassium secretion leads to a decrease in plasma potassium concentration, or hypokalemia.
97. Major cause of death after myocardial infarction?
Fibrillation of the heart
6. Filtration rate =?
Filtration = KF × NFP
52. Kf =? KF is expressed in what units?
Filtration rate/net filtration pressure = KF Units: EX. 15 ML/min/mmHg
17. Under control conditions, flow through a blood vessel is 100 mL/min with a pressure gradient of 50 mmHg. What would be the approximate flow through the vessel after increasing the vessel diameter by 50%, assuming the pressure gradient is maintained at 100 mmHg?
Forget this one 500 ML/min
100. What occurs in unilateral right heart failure?
Increased right atrial pressure Because in acute right heart failure the kidneys retain sodium and water, and the systemic but not the pulmonary veins become congested. Mean pulmonary filling pressure and left atrial pressure do not increase but right atrial pressure increases and edema of the lower extremities including the feet and ankles occurs.
7. A drug is given that decreases the diameter of arterioles in a muscle bed/capillaries. How does this effect vascular conductance, capillary filtration, blood flow?
Increased vascular resistance decrease vascular conductance and blood flow decrease in capillary hydrostatic pressure/filtration rate
49. What increases the net movement of glucose across a capillary wall?
Increasing concentration difference of glucose across the wall.
135. If spinal anesthesia drops blood pressure, causes shock, what do you do to treat it?
Infusion of sympathomimetic drug. Spinal anesthesia drops blood pressure by neurogenic shock, lack of sympathetic tone. The best way to increase sympathetic tone is by infusing a Sympathomimetic drug Not fluids or blood products treat the cause
57. Which pressure is normally negative in a muscular capillary bed?
Interstitial hydrostatic pressure because pumping of the lymphatic system makes the pressure negative
34. Under normal physiological conditions, blood flow to the skeletal muscle is determined mainly by what?
Metabolic needs, local not angiotensin II, vasopressin, capillary osmotic pressure
Net filtration pressure =?
NFP (mmHg) = capillary hydrostatic pressure - plasma colloid osmotic pressure + interstitial colloid osmotic pressure - interstitial hydrostatic pressure.
60. Which of the following is the fastest rate of movement across the capillary wall? Sodium, albumin, glucose, oxygen
Oxygen because it is lipid soluble and can cross the capillary wall with ease, it has the fastest movement across the capillary wall
138. A guy got shot with low blood pressure signs of shock and the blood bank is out of blood. What would you do to prevent shock? Give: glucocorticoid, antihistamine infuse a balance electrolyte solution, infuse a sympathomimetic drug, plasma infusion
Plasma infusion Optimal therapy is to replace the blood that he has lost so pick the next best therapy. Plasma infusion has high colloid osmotic pressure and will help the infused fluid stay in the circulation much longer than a balanced electrolyte solution
144. A 60-year-old woman has been severely burned and has an arterial pressure of 70/40 with a heart rate of 130 bpm. Which of the following therapies would the physician recommend as initial therapy? Blood infusion, plasma infusion, infusion of a balanced electrolyte solution, infusion of a sympathomimetic drug, administration of a glucocorticoid
Plasma infusion: in patients with severe Burns there is a large loss of plasma -like substances from the burned tissues. Therefore, the plasma protein concentration decreases severely and the therapy of choice would therefore be plasma infusion.
107. Which condition normally accompanies acute unilateral right heart failure?
Right atrial pressure increases. Overall cardiac output decreases resulting in a decrease in arterial pressure and urinary output. Left atrial pressure decreases
59. Movement of solutes such as Na+ across the capillary walls occurs primarily by which process?
Simple Diffusion, (semipermeable membrane)
39. True or false. Capillary wall permeability to oxygen is most dependent on oxygen concentration in the blood.
True, O2 concentration trumps capillary hydrostatic pressure, intracellular clefts in the capillary wall, plasma colloid osmotic pressure, capillary wall hydraulic permeability
61. True /false. A decrease in extracellular fluid volume would be expected to occur in response to a direct increase in renal arterial pressure.
True. Increased pressure causes increased diuresis, the loss of sodium and water tends to decrease extracellular fluid volume. GFR would increase.
84. If a person has been exercising for one hour, which of the following organs will experience the smallest decrease flow? Brain, intestines, kidneys, nonexercising skeletal muscle, pancreas
Brain. The brain and the heart maintain their blood flow. Everything else can decrease
5. In a capillary the plasma colloid osmotic pressure = 25 mmHg, capillary hydrostatic pressure = 25 mmHg, interstitial fluid hydrostatic pressure = -5 mmHg, interstitial colloid osmotic pressure = 10 mmHg, KF = 10 mL/min/mmhg. what is the rate of net fluid movement across the capillary wall?
150 mL/min The x2 25's cancel out -5 and 10 add up to 15 outer force pressure KF = 10 10×15 = 150 ML/min
9. A 65-year-old man has congestive heart failure is being treated with an ACE inhibitor. How does this effect arterial pressure, angiotensin II, total peripheral resistance?
Decrease all them, arterial pressure, angiotensin II, total peripheral resistance
40. What vessel has the greatest total cross-sectional area in the circulatory system?
Capillaries. they have more than the aorta, small arteries, venules, vena cava The venous system holds more blood than the arterial system
87. After a heart attack/MI why would the heart fibrillate; after the infarction?
Current of injury from the damaged area. Acute blood loss supply to a cardiac muscle causes depletion of potassium from the cardiac myocytes. This increases ECF potassium levels and increases irritability of the cardiac musculature, increasing likelihood for fibrillation. A more negative membrane potential protects the heart from fibrillation, and a current of injury allows electrical current flow from an ischemic area of the heart to a normal area and can elicit fibrillation.
141. Release of which of the following substances causes vasodilation and increased capillary permeability during anaphylactic shock? Histamine, bradykinin, nitric oxide, atrial natriuretic factor, adenosine
Histamine. It's related allergens, histamine causes venous dilation, dilation of arterioles and greatly increased capillary permeability with rapid loss of fluid and protein into the tissue spaces. This reduces venous return and often results in anaphylactic shock.
13. Bradykinin is infused into the brachial artery of a 22-year-old man. How does this affect capillary hydrostatic pressure, interstitial hydrostatic pressure, lymph flow?
Increase all of them. Bradykinin is a vasodilator that is believed to play a role in regulating blood flow in capillary leakage in inflamed tissue. Infusion of bradykinin into the brachial artery would increase arteriolar diameter and decrease arteriolar resistance. The decrease in arteriolar resistance would also result in an increase in capillary hydrostatic pressure and filtration rate. Increase in filtration rate leads to an increase in interstitial hydrostatic pressure and lymph flow.
11. 55-year-olds blood pressure is 170/98 mmHg. Further tests indicate that he has renovascular hypertension as a result of stenosis in the left kidney. How does his condition affect total peripheral resistance, plasma renin activity, plasma aldosterone concentration?
Increase all of them. Stenosis of one kidney results in the release of renin and the formation of angiotensin II from the affected kidney. Angiotensin II stimulates aldosterone production and increases total peripheral resistance by constricting most of the blood vessels in the body
12. Histamine is infused into the brachial artery. How does this affect the following micro circulatory changes: capillary water permeability, capillary hydrostatic pressure, capillary filtration rate?
Increase all them. Histamine is a vasodilator that is typically released by mast cells and basophils. Infusion of histamine into a brachial artery would decrease arteriolar resistance and increase water permeability of the capillary wall. The decrease in arteriolar resistance would also increase capillary hydrostatic pressure. Increase in capillary hydrostatic pressure and water permeability leads to an increase in capillary filtration rate Think: histamines effect on arterioles, then downstream effect to capillaries
19. What would cause the greatest increase in the net movement of sodium across a muscle capillary wall? Increase or decrease: wall permeability to sodium, wall surface area, concentration difference across wall
Increase all.
28. A 22-year-old man loses 700 mL of blood, his blood pressure is 90/55 mmHg. How does this affect heart rate flow, sympathetic nerve activity and total peripheral resistance?
Increase all. The arterial baroreceptors are activated in response to a decrease in arterial pressure, causing increased SNS outflow. This leads to constriction of peripheral blood vessels, increased total peripheral resistance and a return of blood pressure toward normal. There would be a decrease in parasympathetic nerve activity, an increase in sympathetic outflow which would result in an increase in heart rate.
64. Which of the following would be expected to occur in response to constriction of the renal artery? Increase in sodium excretion, decrease in arterial pressure, decrease in renin release, increase angiotensin II
Increase angiotensin II Constriction of the renal artery increases renin release, angiotensin 2 formation and arterial pressure. Sodium excretion decreases, but only transiently, because as arterial pressure increases, sodium excretion returns to normal levels via a pressure natriuresis mechanism
10. Cognitive stimuli such as reading, problem solving, and talking all result in significant increases in cerebral blood flow. For the increase in cerebral blood flow, what has to happen to carbon dioxide, pH, adenosine?
Increase carbon dioxide, decreased pH, increase adenosine
89. What condition normally causes arteriolar vasodilation during exercise?
Increase plasma adenosine concentration. Also: increases in: potassium ion concentration, plasma nitric oxide concentration, plasma osmolality
14. An increase in shear stress in a blood vessel releases what out of the endothelium?
Increased Nitric oxide nitric oxide increases blood flow by increasing cyclic guanosine monophosphate
48. What organ has the lowest capillary permeability to plasma molecules? Glomerular, liver, muscle, intestinal, brain
The brain because it has tight junctions between capillary endothelial cells that allow only extremely small molecules such as water oxygen carbon dioxide to pass in or out of the brain tissues.
33. True or false. An increase in hydraulic conductivity of the capillary wall and capillary hydrostatic pressure would tend to increase lymph flow.
True
38. Resistance = Delta P/blood flow, true or false. Hint: V = IR
True
42. True/false. An increase in viscosity would be expected to decrease blood flow in a vessel?
True An increase in: pressure gradient across the vessel, plasma colloid osmotic pressure, viscosity of the blood, plasma sodium concentration would increase blood flow in a vessel
45. True /false. An increase in plasma colloid osmotic pressure tends to decrease capillary filtration rate.
True this pressure force holds fluid inside the vessel
58. True or false. Movement of leg muscles would decrease venous hydrostatic pressure in the legs.
True because it causes blood flow to the vena cava which reduces venous hydrostatic pressure.
50. An old guy with CHF has a low cardiac output, normal blood pressure, elevated heart rate, right atrial pressure of 10 mmHg (elevated). An increase in what would be expected?
Vena cava hydrostatic pressure. Plasma colloid osmotic pressure, interstitial colloid osmotic pressure, arterial pressure, cardiac output would all be low to normal
23. The diameter of a precapillary arteriole is decreased in a muscle vascular bed. Would it decrease capillary filtration rate?
Yes
46. Does an increase in capillary wall hydraulic conductivity tend to increase capillary filtration rate?
Yes (capillary wall permeability to water) Plasma sodium concentration has no effect on filtration
36. During exercise does vascular conductance, blood flow, carbon dioxide concentration, and arterial diameter increase?
Yes, during exercise tissue levels of carbon dioxide and lactic acid increase. These metabolites dilate blood vessels, decrease arteriolar resistance, and enhance vascular conductance and blood flow.