1. The following information was obtained in a human subject:

Plasma:
[inulin] = 1mg/ml
[X] = 2 mg/ml

Urine
[Inulin] = 150 mg/ml
[X] = 100 mg/ml
Urine flow rate = 1 ml/min

Assuming that X is freely filtered, which of the following statements is most correct?

A. There is net secretion of X
B. There is net reabsorption of X
C. There is both reabsorption and secretion of X
D. The clearance of X could be used to measure the GRF
E. The clearance of X is greater than the clearance of the inulin
 

2. Which of the following would cause an increase in both GFR and renal plasma flow?

A. Hyperproteinemia
B. A ureteral stone
C. Dilation of the afferent arteriole
D. Dilation of the efferent arteriole
E. Constriction of the efferent arteriole
 

3. A woman has a plasma osmolarity of 300 mOsm/L and a urine osmolarity of 1200 mOsm/L. The correct diagnosis is

A. syndrome of inappropriate antidiuretic hormone (SIADH)
B. water deprivation
C. central diabetes insipidus
D. nephrogenic diabetes insipidus
E. drinking large volumes of distilled water
 
 

4. A patient is infused with para-aminohippuric acid (PAH) to measure renal blood flow (RBF).  She has a urine flow rate of 1 ml/min, a plasma [PAH] of 1 mg/ml, a urine [PAH] of 600 mg/ml, and a hematocrit of 45%.  What is her RBF?

A. 600 ml/min
B. 660 ml/min
C. 1212 ml/min
D. 1333 ml/min
E. not enough information to make this calculation
 
 
 

A woman with a history of severe diarrhea has the following arterial blood values:
pH = 7.25
PCO2 = 24 mmHg
[HCO3-] = 10 mEq/L

Venous blood shows decreased blood [K+]
 

5. The correct diagnosis of this patient is

A. metabolic acidosis
B. metabolic alkalosis
C. respiratory acidosis
D. respiratory alkalosis
E. normal acid-base status
 

6. Which of the following statements about this patient is correct?

A. She is hypoventilating
B. The decreased arterial [HCO3-] is primarily a result of buffering of excess H+ by HCO3-
C. The decreased blood [K+] is a result of exchange of intracellular H+ for extracellular K+
D. The decreased blood [K+] is a result of increased circulating levels of aldosterone
E. The decreased blood [K+] is a result of decreased circulating levels of ADH.
 

7. At plasma concentrations of glucose higher than transport maximum, the

A. clearance of glucose is zero
B. excretion rate of glucose equals the filtration rate of glucose
C. reabsorption rate of glucose equals the filtration rate of glucose
D. excretion rate of glucose increases with the increasing plasma glucose concentrations
E. renal vein glucose concentration equals the renal artery glucose concentration.
 

8. Which of the following lung volume or capacities can be measured directly by spirometry?

A. Functional residual capacity
B. Physiologic dead space
C. Residual Volume
D. Total Lung Capacity
E. Vital capacity
F. More than one of the above can be directly measured
 

9. Which of the following is true during inspiration?

A. Intrapleural pressure is positive
B. The volume in the lungs is less than the functional residual capacity
C. Alveolar pressure equals atmospheric pressure
D. Alveolar pressure is higher than atmospheric pressure
E. Intrapleural pressure is more negative than it is during expiration
F. None of the above are true
 

10. Which of the following will occur as a result moving to a high altitude?

A. Hypoventilation
B. Arterial PO2 greater than 100 mmHg
C. Decreased DPG concentration
D. Shift to the right of the hemoglobin-O2 dissociation curve
E. Pulmonary vasodilation
F. Respiratory acidosis
H. More than one of the above are true
 
 

11. The pH of venous blood is only slightly more acidic than the pH of arterial blood because

A. CO2 is a weak base
B. there is no carbonic anhydrase in venous blood
C. the H+ generated from CO2 and H2O is buffered by HCO3 – in venous blood
D. the H+ generated from CO2 and H2O is buffered by deoxyhemoglobin in venous blood
E. oxyhemoglobin is a better buffer for H+ than is deoxyhemoglobin
F. none of the above explanations are true
 

12. Compared with the apex of the lung, the base of the lung has

A. a higher pulmonary capillary PO2
B. a higher pulmonary capillary PCO2
C. a higher ventilation/perfusion ratio
D. the same ventilation/perfusion ratio
E. none of the above are true
 

13.  If an area of the lung is not ventilated because of bronchial obstruction, the pulmonary capillary blood serving that area will have a PO2 that is

A. equal to atmospheric PO2
B. equal to mixed venous PO2
C. equal to normal systemic arterial PO2
D. higher than inspired PO2
E. lower than mixed venous PO2
F. none of the above are true
 

14. The following data were obtained during a pulmonary function test:

Fraction of CO2 in mixed expired gas: 3.0%
Fraction of CO2 in alveolar gas: 4.5%
Tidal volume: 450 ml
Frequency: 10 breaths per minute

The volume of physiologic dead space is:

A. 100 ml
B. 125 ml
C. 150 ml
D. 225 ml
E. 750 ml
F. none of the above are correct
 
 

15. Which of the following conditions is most likely to produce the change from the normal maximum flow volume curve illustrated below?

A. Asthma
B. Emphysema
C. Bronchiolitis
D. Fibrosis
E. Fatigue
 
 

Use the respiratory data below to answer the following questions (16 – 18)

Tidal volume = 425 ml
Anatomical dead space = 95 ml
Breathing frequency = 10 breaths/min
PACO2 = 55 mmHg
PIO2 = 145 mmHg
 

16. The patient’s alveolar ventilation is

A.3.0 L
B. 3.3 L
C. 4.0 L
D. 4.3 L
E. none of the above are correct
 

17. The patient’s alveolar oxygen tension is approximately

A. 90 mmHg
B. 76.6 mmHg
C. 112.5 mmHg
D. 140 mmHg
E.  145 mmHg
 

18. If the patient increases his tidal volume by 30% without changing his CO2 production or respiratory rate, his PACO2 will be

A. 45.3 mmHg
B. 26.8 mmHg
C. 11.24 mmHg
D. 31.4 mmHg
E. none of the above answers are within 2 mmHg of being correct
 

19. A sick patient is brought to you in the emergency room.  Her plasma osmolarity is 370 mOsm, her plasma volume is 1.7 L and her hematocrit is 45%.

You want to rehydrate the patient with 120 mM of glucose.  Approximately what volume do you give to bring the plasma osmolarity back to normal?  Assume no fluid diffusion into interstitial tissue, that normal osmolarity is 286 mosm and that all glucose will be metabolized.

A. 0.5 L
B. 0.9 L
C. 1.5 L
D. 2.8 L
E. 3.0 L
 

20. Preventing the inactivation of sodium channels will decrease

A. the relative refractory period of nerve cells
B. the upstroke velocity of nerve cell action potentials
C. the downstroke velocity of nerve cell action potentials
D. the magnitude of the overshoot in nerve cell action potentials
E. the duration of nerve cell action potentials
 

21.  Periodic hyperkalemic paralysis is characterized by high potassium concentration in plasma, interstitial fluid and muscle weakness.  Which of the following is likely to cause muscle weakness as a result of increased extracellular potassium concentration?

A. hyperpolarization of muscle cells
B. inactivation of sodium channels in muscle cells
C. increased release of neurotransmitters from alpha motor neurons
D. decreased potassium conductance in muscle cells
E. increased duration of action potentials produced by alpha motor neurons
 
 
 

The diagram of a nerve action potential for the following 3 questions.

22. At which labeled point on the action potential is the K+ closest to its electrochemical equilibrium?

A. 1
B. 2
C. 3
D. 4
E. 5

23. What process is responsible for the change in membrane potential that occurs between point 1 and point 3?

A. movement of Na+ into the cell
B. movement of Na+ out of the cell
C. movement of K+ into the cell
D. movement of K+ out of the cell
E. activation of the Na+/K+ ATPase pumps
F. inhibition of the Na+/K+ ATPase pumps
 

24. What process is responsible for the change in membrane potential that occurs between point 3 and point 4?

A. movement of Na+ into the cell
B. movement of Na+ out of the cell
C. movement of K+ into the cell
D. movement of K+ out of the cell
E. activation of the Na+/K+ ATPase pumps
F. inhibition of the Na+/K+ ATPase pumps
 

25.  A cell has the following electrolyte concentrations: K+ : 90 mEq; Na+ : 3 mEq; Cl- : 2 mEq; Mg+2: 60 mEq.  The ECF concentration of these ions are K+ : 4 mEq; Na+ : 150 mEq; Cl- : 100 mEq; Mg+2: 1 mEq.  The conductance of these ions are K+ : 20 siemens; Na+ : 2 siemens; Cl- :  1 siemens; Mg+2: 0.5 siemens.  The theoretical resting membrane potential for this cell is

A. +64.5 mV
B. –66.5 mV
C. – 63.5 mV
D. +63.5 mV
E. The resting membrane potential is not within 5 mV of the above answers
 

26. A cell membrane has a length constant of 2.5 mm.  If you put an electrical probe into the cell membrane and the reading 2.5 mm from the point of insertion is +15 mV and a normal resting membrane potential is –80 mV, what have you raised the potential to at the point of insertion?

A. 176.8 mV
B. 95.7 mV
C. 336.7 mV
D. 255.7 mV
E. The correct answer is not within 5 mV of the above answers
 

27. You have measured the amperage of sodium to be 0.005 amps when the membrane potential is 15 mV.  There is 20x more sodium on the outside of the cell than inside the cell.  Calculate the conductance in mmhos. (the answers are given below in absolute values)

A. There is not enough information given to do this calculation.
B. 78 mmhos
C. 53 mmhos
D. 64 mmhos
E. 47 mmhos
 

28. Suppose you have a membrane with a sodium conductance of 10 mmhos.  If the Nerst value for sodium is +60 mV, then calculate the amperage of sodium flow when the membrane potential is –15 mV.

A. – 450 mAmps
B. – 0.75 mAmps
C. – 0.45 mAmps
D. – 750 mAmps
E. The correct answer is not within 50 mAmps of the above answers
 
 

A) Only I is true
B) Only II is true
C) Both I and II are true
D) Both I and II are false
 
 

29. I. Tetraethylammonium will increase the period of depolarization during an action potential.

     II. Voltage sensitive potassium channels stay open longer than voltage sensitive sodium channels.
 

30. I. Tetracaine is an anesthetic, which like tetradotoxin, blocks voltage sensitive sodium channels.

     II.  Consider 2 axons A and B.  A is unmyelinated and B is myelinated.  If both have a conductance velocity of 20 m/sec, then axon A is about twice the diameter as B.
 

31. I. 5-HT plays a role in temperature regulation of the body.

     II. In the absence of beta-hydroxylase but in the presence of tyrosine hydroxylase and decarboxylase, tyrosine will be converted into dopamine.
 

32. I.  Heroin is an opioid that is derived from opium poppy seeds.

     II. Skeletal muscle fibers are made of multiple muscle fascicles.  These fascicles are surrounded by perimysium.
 

33. I. During skeletal muscle contraction the I band becomes shorter.

     II. Nebulin is an elongated elastic protein that is attached to the Z discs and runs parallel to the actin myofilaments.
 

34. I. Eccentric isotonic contraction is when the skeletal muscle lengthens.

     II. The “oxygen debt” following strenuous exercise is not paid until the glycogen levels are restored in the muscle tissue.
 

35. I. The calcium-calmodulin complex directly adds a phosphate group into myosin in smooth muscle.

     II. The enteric nervous system modulates gut motility by affecting the slow wave potentials of single unit smooth muscles in the intestines.
 

36. I. In cell membranes, more double bonds in the fatty acid chains will increase the fluidity of that cell membrane.

     II. In gangliosides, a sugar moiety is attached to a choline.
 

37. I. When the internal intercostal muscles contract, the lateral and anterior-posterior diameters increase.

     II. In red blood cells, the HCO3- is transported out by a Na+/ HCO3- counter transporter.
 

38. I. ANP inhibits Na+/K+ ATPase pumps mostly in the collecting tubules/ducts.

     II. If renal clearance of substance X is less than GFR, then substance X must have been filtered.
 

Key:

1. B
2. C
3. B
4. C
5. A
6. D
7. D
8. E
9. E
10. D
11. D
12. B
13. B
14. C
15. D
16. B
17. B
18. E
19. B
20. C
21. B
22. E
23. A
24. D
25. B
26. A
27. B
28. B
29. C
30. A
31. C
32. D
33. A
34. A
35. B
36. A
37. D
38. A