DIRECTIONS: Each of the questions or incomplete statements below is followed by five
suggested answers or completions. Select the ONE that is BEST in each case.
1. Complete inhibition of which one of the proximal tubule transport processes will have the
greatest inhibitory affect on fluid reabsorption in that segment?
(A) Alanine cotransporter
(B) Glucose cotransporter
(C) Sodium:hydrogen exchanger
(D) Sodium pump
(E) PAH transporter
2. During a hydropenic state, a diuretic which inhibits the Na:K:Cl tritransporter at the luminal
membrane of the thick ascending limb of the loop of Henle will result in which of the
following:
(A) A diuresis
(B) Increased K excretion
(C) Increased Na excretion
(D) Decreased urine osmolality
(E) All of the above
3. Osmoreceptors controlling ADH secretion are located in the
(A) kidney.
(B) liver.
(C) hypothalamus.
(D) pituitary.
(E) brain stem.
Answer the following two questions based on the clearance data given below.
Plasma Concentration
Urine Concentration
Creatinine
mg/dl
2
400
PAH
mg/dl
1
800
Urine flow rate = 0.5 ml/min
4. The filtration fraction (FF) is
(A) 0.10
(B) 0.15
(C) 0.20
(D) 0.25
(E) 0.30
5. The rate of reabsorption of alanine (mg/min) is
(A) 40
(B) 80
(C) 100
(D) 160
(E) 200
1
Alanine
mg/dl
80
0
6. During antidiuretic conditions, which of the following tubule segments has the highest urea
permeability?
(A) Thick ascending limb of the loop of Henle.
(B) Thin ascending limb of the loop of Henle.
(C) Distal convoluted tubule
(D) Cortical collecting duct
(E) Inner medullary collecting duct
7. All of the following bring about an increase in renin secretion EXCEPT:
(A) Constriction of a renal artery
(B) Being stranded in a desert without salt or water
(C) Chronic consumption of a diet high in potassium
(D) Movement from a supine to an erect position
(E) Administration of a "converting enzyme" inhibitor
8. All of the following contribute to the diuresis following the intravenous infusion of 3 liters
of isotonic saline EXCEPT:
(A) increase in blood flow to the renal medulla
(B) decrease in plasma oncotic pressure
(C) decreased secretion of renin
(D) decreased secretion of Atrial Natriuretic Peptide
(E) increased hydrostatic pressure in the inferior vena cava
9. Atrial Natriuretic Peptide
(A) brings about constriction of the afferent arteriole.
(B) activates guananylate cyclase.
(C) sensitizes the zona glomerulosa to angiotensin I.
(D) promotes secretion of rennin.
(E) promotes secretion of ADH.
10. Aldosterone does all of the following EXCEPT:
(A) Increases permeability of apical membrane of principal cells of cortical collecting
duct to Na
(B) Increases secretion of H by intercalated cells of cortical collecting duct
(C) Induces synthesis of new proteins
(D) Binds to specific receptors on basolateral membranes of cortical collecting duct
cells
(E) Increases activity of Na-K pumps in cortical collecting duct cells
11. Oxygen dissociation from hemoglobin is enhanced by all of the following EXCEPT:
(A) An increase in local PCO2
(B) Hyperventilation at sea level
(C) Severe exercise
(D) Fever
(E) Chronic pulmonary disease
12. Carbon dioxide is transported in the plasma from the tissues to the lungs primarily in the
form of
(A) dissolved CO2.
(B) HC03(C) carbamino-protein complexes.
(D) H2CO3(E) complexes with heavy metals in the plasma such as Mg2+
2
13. In a patient who has a generalized weakness of her skeletal muscles, but is otherwise
normal, which of the following lung volumes or lung capacities would most likely be
normal?
(A) Total lung capacity
(B) Vital capacity
(C) Residual volume
(D) Inspiratory capacity
(E) Functional residual capacity
14. During normal breathing in the resting state, expiration of the tidal volume is due
primarily to
(A) elastic recoil of the lungs.
(B) elastic recoil of the chest wall
(C) contraction of the internal intercostal muscles.
(D) contraction of the abdominal muscles.
(E) contraction of the diaphragm.
15. Loss of surfactant from the lungs would lead to all of the following EXCEPT:
(A) Collapse of small alveoli into larger communicating alveoli
(B) An increase in residual volume of the lung
(C) An increase in surface tension of the alveoli
(D) A need for a greater pressure difference across the alveoli in order to inhale
(E) An increase in the work of breathing
16. Dynamic compression of the airways is more likely to occur
(A) during inspiration rather than expiration.
(B) at lung volumes closer to total lung capacity rather than residual volume.
(C) when intrapleural pressure is below atmospheric rather than above atmospheric
pressure.
(D) at the base rather than the apex of the lung in a standing person.
(E) if lung elastic recoil is greater than normal.
17. In a normal individual during rest, the work of breathing
(A) occurs mostly during inspiration.
(B) is exerted mostly to overcome airways resistance.
(C) is responsible for about 20% of the total body energy expenditure.
(D) is conducted primarily by the external intercostal muscles.
(E) would be decreased at high altitude compared to sea level.
18. All of the following statements about functional residual capacity are true EXCEPT:
(A) It is independent of muscular activity
(B) It can be measured using a spirometer while breathing only room air
(C) It will be decreased in a person with increased lung elastic recoil
(D) It will be increased in a person with increased chest wall elastic recoil
(E) It is the volume of air remaining in the lung at the end of a normal expiration
3
19. In a subject breathing room air at a tidal volume (VT) of 600 ml, a frequency of breathing of
10 breaths per minute and a dead space volume (VD) of 200 ml, alveolar ventilation (VA)
would be
(A) 2000 ml/min.
(B) 4000 ml/min.
(C) 6000 ml/min.
(D) 8000 ml/min.
(E) impossible to calculate with the information given.
20. Alveoli in the top of the lung compared to those at the bottom of the lung in an upright
normal subject
(A) receive a greater percentage of the tidal volume.
(B) receive a greater percentage of the pulmonary blood flow.
(C) have a lower ventilation/perfusion ratio.
(D) exhibit greater compliance.
(E) have larger radii.
21. When a person goes from resting to exercising, the diffusing capacity of the lung increases
largely due to
(A) thinning of the alveolar membrane.
(B) an increase in the partial pressure of gasses in the alveoli.
(C) an increase in the surface area of the lungs through which diffusion takes place.
(D) an increase in the solubility of the gasses.
(E) an increase in the time blood spends in the alveolar capillaries.
22. All of the following occur during adaptation to high altitude EXCEPT:
(A) Relaxation of vascular smooth muscle in the pulmonary circulation
(B) Increased ventilation
(C) Decreased PaCO2
(D) Increased red blood cell concentration (polycythemia)
(E) Increased density of open capillaries in body tissues
23. The following data were obtained on a patient breathing room air at sea level: PaO2 = 55
mm Hg, PaCO2 = 32 mm Hg, pHa = 7.45, and R = 0.8. CO2 production was normal. When
the patient breathed 60% oxygen, the Pa02 increased to 120 mm Hg. The low PaO2 when
breathing room air was due most likely to
(Alveolar gas equation: PAO2 = FIO2 (PB - PH2O) - PaCO2 / R where FIO2 = 0.21 for
air and PH2O = 47 mmHg at body temperature.)
(A) shunt.
(B) ventilation/perfusion inequality.
(C) hypoventilation.
(D) weak muscles of respiration.
(E) anemia.
24. The rate of bicarbonate reabsorption by the kidney would be greatest in which of the
following conditions?
(A) Uncompensated Respiratory Acidosis
(B) Compensated Respiratory Acidosis
(C) Uncompensated Respiratory Alkalosis
(D) Compensated Respiratory Alkalosis
(E) Metabolic Acidosis
4
25. Weak acids in the glomerular filtrate facilitate HCO3 reabsorption by which of the
following:
(A) Combining with secreted H+ to prevent it from reacting with HCO3
Keeping the pH of the tubular lumen alkalotic to favor the dehydration of carbonic
acid
(C) Reducing the pH of the tubular lumen
(D) Buffering secreted H+
(E) Reacting with and neutralizing HCO326. A patient is suffering from acute diabetic ketoacidosis. When you see the patient he is
hyperventilating. The main drive for the increased ventilatory rate is:
(A) a fall in the plasma [HCO3].
(B) an increase in the plasma PCO2 due to reaction of the ketoacids with HCO3 .
(C) H+ stimulation of central chemoreceptors.
(D) an increase in the arterial [H+].
(E) CO2 stimulation of central chemoreceptors.
The next two questions refer to the following data.
Plasma [HCO3-]= 30 meq/1
Arterial PCO2 = 33 mmHg
Plasma [K+] = 4 meq/1
27. What is the plasma pH?
(A) 6.8
(B) 7.0
(C) 7.2
(D) 7.4
(E) 7.6
28. From the information provided, the appropriate renal response to this condition would be:
(A) increased ammoniagenesis.
(B) reabsorb all filtered HCO3- and excrete an acidic urine.
(C) excrete HCO3- in an alkaline urine.
(D) decrease carbonic anhydrase activity.
(E) increased K+ secretion.
29. An anesthetized experimental animal is on a ventilator with pure oxygen. The ventilatory
rate is doubled and accompanied by a fall in the arterial PCO2. Why is there a fall in PaCO2?
(A) Since the animal is on a ventilator there is less energy expenditure and thus less
production of CO2
(B) Alveolar PCO2 is determined by the ventilatory rate.
(C) There is low CO2 in the inspired gas.
(D) Excretion of CO2 is greater than the rate of CO2 production due to the higher rate of
ventilation.
(E) All of the above.
5
DIRECTIONS: Each group of questions below consists of four or five lettered headings or a
diagram or table with four or five lettered components, followed by a list of numbered words,
phrases, or statements. For each numbered question, select the ONE lettered heading or
component that is MOST CLOSELY ASSOCIATED WITH IT. Each lettered component or
heading may be selected once, more than once, or not at all.
(A) Constriction of the renal afferent arteriole only
(B) Constriction of the renal efferent arteriole only
(C) Constriction of both the afferent and efferent arterioles
(D) Dilation of the afferent arteriole only
(E) Dilation of both the afferent and efferent arterioles
For each of the following conditions/states, select the letter of the most likely response of the
afferent/efferent arterioles to the condition/state.
30. _____ A few minutes after drinking one liter of water
31. _____ Autoregulation following elevation of renal arterial pressure
-------------------------------------------------------------------------------------------------------------A. Diabetes mellitus
B. Diuretic blockade of the Na:K:Cl cotransporter
C. Diabetes insipidus
D. Saline diuresis
For each of the following conditions, select the letter of the diuretic state which is associated
with the condition.
32. ______ Hypotonic urine
33._______Osmotic diuresis
-----------------------------------------------------------------------------------------------------------------(A) Clearance of Inulin
(B) Clearance of PAH
(C) Both
(D) Neither
34._________ Increased following rapid intravenous infusion of one liter of isotonic saline
35. _________ Increased following sympathetic nerve stimulation
--------------------------------------------------------------------------------------------------------------Normal
A
B
C
D
Total lung capacity, L (TLC)
Vital capacity, L (VC)
Forced expiratory volume
(FEV 1/FVC)
Functional residual capacity, L
(FRC)
Maximum expiratory flow
rate, L/min. (MEFR)
6
4.8
83%
7
2.1
25%
4
2.1
50%
4
3.5
83%
6
4.8
25%
2.2
3.2
2.2
1.2
2.2
400
40
100
200
40
6
36. _____Weakness of the muscles of respiration
37. _____ Increased dynamic compression of the airways
38. _____Increased elastic recoil of the lungs
------------------------------------------------------------------------------------------------
A.
B.
C.
D.
E.
Respiratory
Minute
Volume
Plasma pH
Plasma
HCO3-
Plasma CO2
Urine pH
↑
↓
↑
↑
↓
↑
↑
↓
↓
↑
↓
↑
↑
↓
↑
↓
↑
↓
↓
↑
↑
↓
↓
↓
↑
39. _____ Diabetic ketoacidosis
40. _____ Chronic administration of aldosterone
41. _____ One day after ascent to high altitude
7
PHYSIOLOGY 2003
EXAM III
1. D
2. E
3. C
4. D
5. B
6. E
7. C
8. D
9. B
10. D
11. B
12. B
13. E
14. A
15. B
16. D
17. A
18. B
19. B
20. E
21. C
22. A
23. B
24. B
25. D
26. D
27. E
28. C
29. B
30. E
31. A
32. C
33. A
34. C
35. D
36. B
37. A
38. C
39. D
40. B
41. A
8