PhysiologyExam I

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

1.       I. Sphingomyelin is made of 2 fatty acid chains, a sphingosine and a serine.

II. A choline, which is an alcohol with a nitrogen group, is directly connected to the glycerol moiety on phosphotidyl choline.
2.       I. Van der Waal's forces are relatively weak forces between molecules in solution. Typically the bonds are only about 100 calories of heat per mole.
II. Van der Waal's forces are a greater factor in attraction between phospholipid molecules with saturated fatty acids compared to unsaturated fatty acids.
3.       I. Gangliosides, which are cell surface molecules, are bound to integral proteins in the cell membrane.
II. If one knows the number of atmospheres of osmotic pressure of a solution, the ideal gas constant and temperature but NOT the osmotic coefficient, one could still calculate the exact osmolarity of that solution.
4.      I. The sodium-potassium ATPase transporter will cause the inside of the cell to become more negatively charged if there are no other compensatory movement of ions by either leaks through the membrane or other pumps.
II. The concentration gradient across a typical cell membrane of potassium is approximately that of sodium.
5.       I. Unlike a primary active transport, a secondary active transport cannot move a molecule across the cell membrane against its concentration gradient.
II. An extracellular chemical messenger, binding to a receptor, which activates a G protein, may lead to opening calcium channels and an increase in intracellular calcium levels.
6.       I. Diacylglycerol can activate inositol triphosphate leading to an increase in cytosolic calcium levels.
II. Protein kinases can be involved in phosphorylating proteins.
7.      I. The major activator of protein kinase C is cAMP.
II. Activation of calmodulin leads to the increase in cytosolic calcium levels.
8.       I. The apneustic center, which is part of the respiratory center in the pons, is active during exercise. It inhibits the neurons of the pneumotaxic center.
II. Damage to the vagus nerve could lead to over inflation of the lungs.
9.       I. Both the carotid bodies and aortic bodies are very sensitive to PO2 and PCO2 but not plasma H+ concentration.
II. Most of the CO2 in the blood is transported in dissolved form.
Choose the most correct answer.

10. Suppose a container had two chambers, A and B, filled with a solution. Chamber A had 20 mg/L of a substance and chamber B had 10 mg/L of the same substance, and the membrane between the two chambers was permeable to that substance. If the concentration of the substance in chamber A doubles, the diffusion of the substance will change from 10 mg/hour to

a. 5 mg/hr
b. 10 mg/hr
c. 15 mg/hr
d. 20 mg/hr
e. 30 mg/hr
 

11. A red blood cell will initially swell the most when placed in a infinite solution containing

a. 100 millimolar calcium chloride
b. 200 millimolar potassium chloride
c. 250 millimolar urea
d. 300 millimolar sucrose
e. the red blood cell will not swell in any of the above solutions

Questions 12-14

The diagram below represents a spirometry tracing illustrating the changes in lung volume that occurred when a subject inhaled maximally and then rapidly exhaled as much gas as possible.
 

12. If the patient's total lung capacity is 6 L, what is the functional residual capacity?

a. 1L
b. 2L
c. 3L
d. 4L
e. 5L

13. What is the inspiratory capacity?

a. 1.0 L
b. 1.5L
c. 2.0L
d. 2.5L
e. 3.0L

14. What is the FEV1?

a. 1.5L
b. 2.5L
c. 3.5L
d. 4.5L
e. 5.5L

Questions 15-17

Use the respiratory data below to answer the following questions.

Tidal volume = 400 ml
Anatomical dead space = 100 ml
Breathing frequency = 10 breaths/min
PACO2 = 50 mmHg
PIO2 = 150 mmHg

15. The patient's alveolar ventilation is

a. 3L/min
b. 4L/min
c. 5L/min
d. 6L/min
e. none of the above

16. The patient's alveolar oxygen tension is approximately

a. 70 mmHg
b. 80 mmHg
c. 88 mmHg
d. 98 mmHg
e. 110 mmHg

17. If the patient doubles his tidal volume without changing his CO2 production or respiratory rate, his PACO2 will approximately be

a. 15 mmHg
b. 20 mmHg
c. 25 mmHg
d. 30 mmHg
e. 35 mmHg

18. Which one of the following would increase in obstructive but not in restrictive lung disease?

a. vital capacity
b. maximum expiratory flow rate
c. FEV1
d. functional residual capacity
e. breathing frequency

19. Which of the conditions causes a decrease in arterial O2 saturation without a decrease in arterial O2 tension?

a. right to left shunt
b. carbon monoxide poisoning
c. a low V/Q ratio
d. hypoventilation
e. none of the above

20. A deficiency of pulmonary surfactant would

a. decrease surface tension in the alveoli
b. decrease the change in intrapleural pressure required to achieve a given tidal volume
c. decrease lung compliance
d. decrease work of breathing
e. increase functional residual capacity
 

Use the following graph for questions 21 and 22
 

21. What is the P50 of the oxyhemoglobin curve labeled A in the above diagram?

a. 5 mmHg
b. 30 mmHg
c. 35 mmHg
d. 40 mmHg
e. 45 mmHg

22. Which of the following conditions is most likely to shift the above oxyhemoglobin curve from A to B?

a. increased temperature
b. exercise
c. acclimatization to high altitude
d. hyperventilation
e. metabolic acidosis

23. A young skier with normal pulmonary function (minute volume 4L; pulmonary blood flow 5L/min) who is recovering from a tibial fracture suddenly develops right-sided chest pain and tachypnea (rapid breathing). Embolic occlusion of the right pulmonary artery is suspected. The diagnosis would be confirmed by which of the following gas measurement of expired alveolar air.


 

24. The oxygen required by the respiratory muscles would be increased by all of the following EXCEPT

a. a decrease in lung compliance
b. a decrease in airway resistance
c. an increase in the rate of respiration
d. a decrease in the production of pulmonary surfactant
e. an increase in tidal volume

For each of the situations described, choose the combination of arterial blood gas changes in the table with which it is most likely to be associated. Answers may be used more than once.
 
 
 
 

25. Sudden ascension to a high altitude

26. Metabolic acidosis

27. Respiratory arrest
 

28. A person exposed to carbon monoxide, <0.02 mmHg PCO (non-lethal), will have

a. an increase in ventilation
b. a slight decrease in ventilation
c. no change in ventilation
d. a cessation of breath
 

29. A health person is performing moderate exercise. Which of the following would be increased compared to normal?

a. arterial PCO2
b. venous PO2
c. diffusing capacity
d. arterial pH
e. none of the above

30. A mother and her infant girl comes into the emergency room. The mother tells you that the baby has had severe diarrhea to 2 days. You run a blood test and find the following:

plasma osmolarity: 360 mOsm/L
plasma volume: 0.3L
hematocrit: 60%

You want to rehydrate the little girl with 180 mM solution of glucose. What volume do you give to bring plasma osmolarity back to normal? Assume no fluid diffusion into interstitial tissue and normal osmolarity is 286 mosm/L. Show all steps with units by each number. Also assume over time all glucose is metabolized.
 

31. Assuming you had access to standard equipment of a pulmonary lab (spirometer, instruments to measure gas concentrations, tanks of nitrogen, helium, oxygen, carbon dioxide, etc., how could you measure a patient's residual volume. This question can be answered in a couple of sentences.

Answer Key

1. d
2. c
3. b
4. c
5. b
6. b
7. d
8. c
9. d
10. e
11. c
12. c
13. e
14 c
15. a
16. c
17. b
18. d
19. b
20. c
21. b
22. d
23. b
24. b
25. g
26. d
27. e
28. c
29. c
30. 0.194 L
31. See your text.