HBY 531 Organ Systems
Mid-Term Examination
1995
Section 1: Answer the following using:
A = becomes more negative
B = remains unchanged
C = becomes more positive
1. The maximum diastolic potential in a ventricular myocyte __________ when external [K+] is lowered from 8 to 3 millimolar.
2. The maximum diastolic potential in a Purkinje myocyte __________ when the external [K+] is lowered from 5 to 1 mM.
3. The maximum diastolic potential in the sinus node __________ when the vagus nerve is stimulated.
Section 2: Answer the following using:
A = increases
B = no change, or remains unchanged
C = decreases
4. The duration of the P wave of the electrocardiogram __________ when the conduction in the Purkinje system is slowed.
5. The duration of the sinus node action potential __________ when the vagus nerve is stimulated.
6. The speed of conduction of the Purkinje fiber action potential __________ when the external [Na+] is reduced by a factor of two.
7. The amplitude of the L-type calcium current ___________ when the sympathetic nervous system is stimulated.
8. The slope of phase 4 in Purkinje fibers __________ when the external [K+] is raised from 3 to 6 mM.
9. Systemic arteriolar diameter __________ in response to sympathetic stimulation.
10. In a patient with severe asthma, total lung volume __________.
11. As individuals train, their maximum oxygen utilization __________.
12. As one returns from high altitude conditions, ventilation __________ from that observed before first ascent.
13. Endothelialderived factors such as prostacyclin (PGI2) and nitric oxide (NO) can locally induce __________ in vascular smooth muscle tone.
14. As respiration rate increases, resistive work of breathing
__________.
15. As cardiac output increases, vascular compliance __________.
16. As venous return increases, cardiac output __________. ()
17. As the length of a vessel with a fixed diameter increases, the overall resistance of that vessel __________. ()
18. As residual volume (RV) increases, functional residual capacity __________. ()
19. During anemic conditions, the oxygen content of the blood __________. ()
20. Activation of alpha adrenergic receptors on salivary gland arterioles leads to ___________ in the diameter of those same vessels. ()
21. Activation of beta adrenergic receptors on coronary arterioles leads to ___________ in the diameter of those same vessels. ()
22. Increases in the systemic plasma protein concentration will lead to __________ in the net filtration pressure in the glomerulus. ()
23. Inhibition of angiotensin converting enzyme will lead to __________ in proximal tubular sodium reabsorption. ()
24. A rise in plasma ADH levels will lead to __________ in proximal tubular water reabsorption. ()
25. Increasing dietary sodium intake from a low to a high level will lead to __________ in plasma aldosterone concentrations. ()
26. An increase in the plasma angiotensin II concentration will lead to __________ in the renal renin secretion rate. ()
27. Inhibtion of ADH action will lead to __________ in the urea reabsorption in the inner medullary collecting ducts.
28. A fall in plasma [Ca2+] will lead to __________ in renal activation of vitamin D. ()
29. A rise in plasma PTH will lead to __________ in renal phosphate excretion. ()
30. Intravenous infusion of NaOH will lead to __________ in proximal tubular bicarbonate reabsorption. ()
31. Respiratory compensation for a metabolic acidosis involves __________ in alveolar ventilation. ()
Section 3: For each of the following statements, choose A if the statement is true, or B if the statement is false.
32. A large increase in the chloride conductance contributes to acetylcholine's action of the SA node.
33. The upstroke of the action potential in the SA node can be blocked by TTX.
34. Treating an isolated papillary muscle (kept at a set preload) with epinephrine will increase the weight of the afterload it can lift.
35. Increasing the preload on an isolated papillary muscle will increase its maximum velocity of contraction when stimulated.
36. Stimulating the sympathetic supply to the heart will lengthen diastasis.
37. If a patient's systolic pressure is 150 mm Hg and his diastolic pressure is 90 mm Hg, then his mean pressure is 110 mm Hg.
38. Most of the total blood volume is contained in the venous
system which has the largest cross sectional area of all the vascular compartments.
39. When discussing velocity in terms of hemodynamics, one is
considering the movement of blood past a particular point per unit time.
40. At endexpiration, pleural pressure is negative and airway
pressure is atmospheric.
41. During an extended stay at high altitude, the pH of the CSF
will be proportionately lower than the blood pH.
42. Fluid flow through the lymphatics is promoted by selfcontained lymphatic valves.
43. Nervous control of the entire peripheral vasculature is
accomplished by parasympathetic inhibition and sympathetic stimulation of vascular resistance.
44. In active muscles, lactic acid may lessen the tone in contained blood vessels.
45. Inflation of the lungs stimulates stretch receptors in the lung.
Section 4: For each of the following, choose the single best response.
Questions 46-50 refer to the ECG and pressure volume loop shown below. For these questions, regard the QRS as a single event.
FIGURE 1
46. Which elevation on the ECG is closest to the dicrotic notch?
a. P
b. QRS
c. T
47. Which elevation on the ECG is closest to the C elevation of the venous pulse?
a. P
b. QRS
c. T
48. Which elevation on the ECG is closest to the A elevation of the venous pulse? ()
a. P
b. QRS
c. T
49. Which elevation on the ECG is closest to point B on the pressure-volume loop?
a. P
b. QRS
c. T
50. Which elevation on the ECG is closest to point D on the pressure-volume loop? ()
a. P
b. QRS
c. T
51. An excercising person is consuming 1500 ml/min of O2. Right ventricular blood contains 0.10 ml O2/ml. Arterial blood contains 0.2 ml O2/ml. What is her cardiac output?
a. 15 ml/min
b. 3 x 103 ml/min
c. 15 liters/min
d. 150 ml/min
e. 3 liters/min
52. Which of the following conditions best describes lung mechanics as the lungs inflate from 70% total lung capacity (TLC) to TLC? ()
a. Elastic recoil (Pel) is equal but opposite to the force
generated by the chest wall (Pbs).
b. Pel is small and Pbs is the predominant force acting on
the lung.
c. Pel but not Pbs begin to exert forces on the that act in
concert to deflate the lung.
d. Pel is the only force acting on the lung and tends to
deflate the lung.
e. None of the above.
53. The rheological properties of blood significantly contribute to the flow of blood through the vasculature. Which of the following statements concerning blood rheology is true?
a. Viscosity of the blood decreases as tube diameter
decreases.
b. As shear rate increases shear thinning decreases
apparent viscosity.
c. At low flow rates, leukocytes marginate at the vessel
wall and increase apparent viscosity.
d. As red cell flexibility increases axial flow is
increased.
e. All of the above.
54. Which of the following are examples of conditions that add to the dead space in the lung? )
a. Bronchiolar obstruction.
b. A two foot snorkel.
c. Pulmonary embolism.
d. Arteriovenous shunting.
e. All of the above.
55. Peripheral edema is produced by all of the following entities except:
a. filariasis.
b. decreased colloid osmotic pressure.
c. histamine release.
d. venous occlusion.
e. hypotension.
56. If a given barometric pressure at altitude is 460 torr. What is the approximate prevailing PO2 at this altitude?
a. 46 torr.
b. 75 torr.
c. 118 torr.
d. 93 torr
e. None of the above.
57. Which of the following does not occur at the tissue level of gas exchange in muscle?
a. An decrease of carbaminohemoglobin in the RBC.
b. Chloride shifts into RBC to maintain anionic balance.
c. An increase in the amount of oxygenated myoglobin.
d. The affinity of hemoglobin for oxygen decreases.
e. Plasma carries an increase in bicarbonate ions.
58. During maximal ventilation with forced expiration which of the following events occurs?
a. Phrenic and external intercostal nerve impulses are
prominent.
b. Phrenic, but not intercostal nerve impulses are
prominent.
c. External and internal intercostal, but not phrenic, nerve impulses predominate.
d. Phrenic and internal intercostal nerve impulses
predominate.
e. None of the above.
59. Which of the following statements about central control of
ventilation is false?
a. Sectioning of the brain stem above the apneustic center
prevents all breathing efforts.
b. The apneustic center controls the inspiratory effort.
c. The pneumotaxic center functions to terminate
inspiration.
d. The ventrallateral aspect of the medulla is sensitive to hydrogen ions and will so regulate ventilation.
e. The medullary centers tend to set a respiratory rhythm or oscillation which is then controlled by higher centers.
60. Which of the following statements concerning the oxyhemoglobin dissociation relationship is true?
a. At PO2 = 100 torr blood is fully saturated.
b. Fully saturated, hemoglobin contains 20 vols %.
c. 100 cc of blood contains 15 gm% of hemoglobin.
d. Venous blood carries 15 vols% of oxygen.
e. All of the above.
61. When speaking of Zone III conditions of flow in the lung,
a. alveolar pressure exceeds arterial and venous pressures.
b. arterial pressures exceeds both alveolar and venous
pressures.
c. arterial pressure exceeds venous pressure, and both
exceed alveolar pressure.
d. alveolar pressure exceeds venous pressure, but not
arterial pressure.
e. None of the above.
62. Smooth muscle is found in all of the following structures except:
a. arteries.
b. veins.
c. alveolar ducts.
d. respiratory bronchioles.
e. c & d.
63. A patient is found to have a pH of 7.25 and a PCO2 of 40 torr. Which of the following conditions exist?
a. Metabolic alkalosis with respiratory compensation.
b. Acidosis with respiratory compensation.
c. Respiratory alkalosis without respiratory compensation.
d. Pure respiratory acidosis.
e. None of the above.
64. Which of the following statements about the pressurevolume
relationship in the lung (compliance) is false?
a. Emphysema increases lung compliance.
b. Decreased elasticity of lung tissue increases compliance.
c. As one increases the viscosity of the lung, the
compliance decreases.
d. Respiratory distress in the newborn increases compliance.
65. Which of the following substances act as bronchodilators?
a. Epinephrine.
b. Histamine.
c. PGf2a
d. 5HT.
e. Sympathetic stimulation.
66. The carotid and aortic bodies are most sensitive to:
a. a decrease in CO2.
b. an increase in PO2.
c. a decrease in arterial pressure.
d. a decrease in pH.
e. none of the above.
67. Which of the following statements best describes the function(s) of the surfactant system in the human lung?
a. As the lung inflates, surfactant increases alveolar surface tension.
b. The hydrophobic nature of surfactant keeps the alveoli dry.
c. As the lung deflates, surfactant functions to reduce surface tension.
d. The presence of surfactant ensures relatively even inflation of the lung.
e. All of the above.
68. The atmosphere in a jet flying at high altitude is adjusted to meet the passengers' physiological needs by:
a. changing the ratio of O2 and CO2.
b. increasing the O2 content of the cabin air.
c. increasing the cabin CO2.
d. increasing the cabin pressure.
e. decreasing the atmospheric pressure in the cabin.
69. Oxyhemoglobin releases oxygen more slowly when the:
a. pH is more acid.
b. pH is more alkaline.
c. carbon dioxide is elevated.
d. carbaminohemoglobin levels are low.
e. None of the above.
70. Restrictive lung diseases are characterized by:
a. increases in airway resistance.
b. increases in functional residual capacity.
c. increased lung compliance.
d. decreases in tidal volume.
e. None of the above.
71. When one blows up a balloon, the increased tidal volume is typically drawn from:
a. inspiratory reserve volume.
b. expiratory reserve volume.
c. residual volume.
d. expanded total lung capacity.
e. Just a & b.
72. The majority of the CO2 in the blood is carried by:
a. carbaminohemoblobin.
b. CO2 dissolved in the plasma.
c. bicarbonate ion.
d. 2,3, DPG.
e. plasma proteins.
73. The respiratory center that terminates inspiration is the:
a. pneumotaxic center.
b. apneustic center.
c. medullary inspiratory center.
d. reticular activating system.
e. pontine expiratory center.
74. Which of the following statements about the relationship between oxygen and hemoglobin is false?
a. Myoglobin has a higher affinity for O2 than normal adult
hemoglobin.
b. Low hemoglobin (Hb<15gms%) will decrease blood O2
saturation.
c. Fetal Hb has a higher affinity for O2 than the maternal
Hb.
d. Oxygen content of the blood is in part dependent on PO2.
e. As H+ concentrations increase, saturation of Hb
decreases.
75. Which of the following statements relating central venous pressures and cardiac output is false?
a. Cardiac output is a linear function of central venous
pressure.
b. Changes in blood volume produce parallel changes in
cardiac output.
c. When central venous pressure drops below 0, cardiac
output falls to 0 as well.
d. Changes in arteriolar resistance produce nonparallel
changes in the relation between cardiac output and venous pressures.
e. As venous return increases cardiac output increases
proportionately.
76. Bonnie Blair, the Olympic and World Champion speed skater, has a resting tidal volume of 900cc, a respiratory rate of 12/minute, and total deadspace of 120cc. What is her alveolar ventilation?
a. 9360 cc/min
b. 12240 cc/min
c. 10800 cc/min
d. 8360 cc/min
e. 2340 cc/min
77. A patient visits your office and you discover that his O2 arterial saturation is 95% (not 97 as per normal) and a venous saturation of 77%. What % of this patient's blood flow is shunted through the lungs without gas exchanging?
a. 0.1%
b. 10%
c. 0.9%
d. 20%
e. 2%
Questions 78-80 use the figure below which shows the filtered load and excretion rate of substance X.
FIGURE 2
78. Which of the following best describes the renal handling of substance X? Assume that substance X is freely filtered and not metabolized in the kidney.
a. no net tubular transport
b. net secretion
c. net reabsorption
d. both secretion and reabsorption occur.
e. there is not enough information to determine anything about tubular transport.
79. What is the Tm of substance X?
a. There is no apparent Tm for substance X.
b. There is not enough information to determine the Tm.
c. 0.2 ug/ml
d. 100 ml/min
e. 20 ug/min
80. How would the renal clearance of substance X compare to the clearance of inulin?
a. Both clearances are the same.
b. The clearance of X is larger than the clearance of inulin.
c. The clearance of X is smaller than the clearance of inulin.
d. There is not enough information to make the comparison.
81. A person is infused with PAH, and after equilibration, PPAH is 0.02 mg/ml. At this time, urine flow is 2 ml/min and UPAH is 3 mg/ml. What is renal plasma flow?
a. 200 ml/min
b. 300 ml/min
c. 500 ml/min
d. 1000 ml/min
e. none of the above are correct
82. A person has an arterial PCO2 of 65 mm Hg, and a plasma [bicarbonate] of 24 mM. What is plasma pH?
a. 7.02
b. 7.19
c. 7.34
d. 7.52
e. none of the above are within 0.1 pH units from the correct pH.
83. A person has a plasma pH of 7.53, a plasma [bicarbonate] of 40 mM, and an arterial PCO2 of 50 mm Hg. How would you describe the acid base status of this person?
a. normal
b. respiratory alkalosis
c. respiratory acidosis
d. metabolic alkalosis
e. metabolic acidosis
84. A person has a urine flow of 1.5 liters/day, and urinary concentrations of ammonium, titratable acid, and bicarbonate of 5, 6, and 1 mM, respectively. What is the net rate of renal acid excretion?
a. 15 mmoles/day
b. 18 mmoles/day
c. 11 mmoles/day
d. 60 mmoles/day
e. none of the above are within 1 mmole/day of the correct answer.
85. Which of the following is not transported across the apical membrane in the proximal tubule by a sodium-coupled secondary active transport mechanism (symporter or antiporter)?
a. glucose
b. urea
c. hydrogen ions
d. phosphate
e. all of the above
86. Which of the following mechanisms is not significantly involved in sodium reabsorption in the principal cells in the late distal tubules and collecting ducts?
a. passive sodium diffusion through apical membrane sodium channels
b. passive sodium diffusion through the tight junctions
c. active extrusion of sodium from the cell via Na,K-ATPase located in the basolateral membrane
d. neither a nor b are involved.
e. a, b, and c all contribute significantly to principal cell sodium transport.
87. Which of the following statements about the ionic composition of the body fluid compartments is not true?
a. Extracellular [Na+] is much higher than intracellular [Na+].
b. The total intracellular phosphate concentration is higher than in extracellular fluid.
c. The total intracellular calcium concentration is the same as the concentration of free calcium.
d. The concentrations of sodium and chloride are not identical in extracellular fluid.
e. Intracellular [protein] is higher than extracellular [protein].
88. Which of the following will produce similar relative increases in the volumes of the intracellular and extracellular fluid compartments?
a. increased capillary permeability to plasma protein in a person with normal kidney function.
b. ingestion of 2 liters of pure water.
c. ingestion of 300 mmoles of isotonic sodium chloride.
d. only a and b.
e. a, b, and c.
89. Which of the following statements about renal medullary countercurrent multiplication is not true?
a. The high concentrations of sodium and chloride in the medullary interstitium results from the reabsorption of these ions by the cells of the collecting ducts.
b. Countercurrent multiplication does not occur in the vasa recta.
c. Urea is passively secreted into the tubular fluid in the thin ascending limb.
d. In an antidiuresis, the tubular fluid entering the outer medullary collecting ducts will be isotonic with respect to plasma.
e. In an antidiuresis, urea is passively reabsorbed in the inner medullary collecting ducts.
90. Which of the following statements about renal epithelial H+ secretion is not correct?
a. H+ secretion will rise when either plasma pH falls or plasma PCO2 rises.
b. H+ secretion will be decreased by inhibition of cytosolic carbonic anhydrase.
c. H+ secretion in the proximal tubule occurs via both Na+- H+ antiport and an H+-ATPase.
d. H+ secretion into the lumen of the proximal tubule reduces tubular fluid [bicarbonate].
e. A relatively small fraction of the secreted protons are buffered in the tubular fluid.