MCQs with their answers on respiratory physiology

Admin عدد المساهمات : 9700 تاريخ التسجيل : 06/08/2009

Indicate the best answer or completion.

1. Due to polio, a patient suffers total paralysis of his intercostal muscles. For this patient, which of the following values would still be expected to be essential normal?

A. inspiratory reserve volume (IRV)
B. expiratory reserve volume (ERV)
C. total lung capacity (TLC)
D. vital capacity (VC)
E. none of the above

2. A child with normal lung volumes for his age (TLC = 2.5 liters, VC = 2.0 liters, ERV = 0.5 liters) would expected to have an FEV1 (one-second forced expired volume) in the range of

A. 0.5-1.0 liters
B. 1.0-1.6 liters
C. 1.6-2.0 liters
D. 2.0-2.5 liters
E. 2.5-3.0 liters

3. Contraction of the abdominal muscles is important in

A. normal (quiet) inspiration
B. forced (maximum) inspiration
C. normal (quiet) expiration
D. forced (maximum) expiration
E. none of the above

4. Alveolar surfactant acts to increase pulmonary

A. surface tension
B. compliance
C. airway resistance
D. blood flow
E. both B and D above

5. Administration of an agonist for which of the following autonomic receptors would be expected to cause airway resistance to decrease?

A. muscarinic-cholinergic
B. nicotinic-cholinergic
C. alpha-adrenergic
D. beta-adrenergic
E. histaminic

6. In emphysema, which of the following would be expected to be below normal (less positive or more negative than normal)?

A. airway resistance
B. lung compliance
C. intrapleural pressure
D. FEV1
E. B, C, and D above

7. At which of the following times in the respiratory cycle is the intrapleural pressure most negative?

A. just after the beginning of inhalation (inspiration
B. just before the end of inhalation
C. just after the beginning of exhalation (expiration)
D. just before the end of exhalation
E. any of the above, since the intrapleural pressure is constant during the normal respiratory cycle

The following questions refer to measurements taken on a male subject, age 25, at rest. Indicate whether the value given for a particular measurement is above the value that would be expected for a normal subject, below normal, or contained within the normal range.

8. Residual volume of 2.5 liters

A. above normal
B. below normal
C. within the normal range

9. Intrapleural pressure with relaxed respiratory muscles of -5 cmH2O

A. above normal (less negative than normal)
B. below normal (more negative than normal)
C. within the normal range

10. PEF (peak expired flow rate) of 250 liters/minute

A. above normal (less negative than normal)
B. below normal (more negative than normal)
C. within the normal range

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Answer
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[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة]

sunny

Admin عدد المساهمات : 9700 تاريخ التسجيل : 06/08/2009

1. Cyanosis (a bluish color of the skin and mucous membranes) indicates a higher than normal blood concentration of

A. carbon dioxide
B. carbon monoxide
C. hydrogen ion
D. diphosphogycerate (DPG)
E. reduced hemoglobin

2. As blood passes through systemic capillaries, what happens to the affinity of hemoglobin for oxygen and what happens to the Hb-O2 dissociation curve?

A. Hb affinity for O2 increases and the dissociation curves shifts to the left
B. Hb affinity for O2 increases and the dissociation curves shifts to the right
C. Hb affinity for O2 decreases and the dissociation curves shifts to the left
D. Hb affinity for O2 decreases and the dissociation curves shifts to the right
E. neither Hb affinity for O2 nor the Hb-O2 dissociation curve change

3. Suppose a person has a genetic defect causing him to continue to produce fetal hemoglobin (rather than normal hemoglobin) throughout adult life. What would be the expected systemic arterial oxygen partial pressure and saturation (compared to a normal person)?

A. higher Pa-O2 and higher Hb O2 saturation
B. higher Pa-O2 but lower Hb O2 saturation
C. lower Pa-O2 but higher Hb O2 saturation
D. lower Pa-O2 and lower Hb O2 saturation
E. normal Pa-O2 but higher Hb O2 saturation

4. Compared with systemic arterial blood, pulmonary arterial blood has a higher

A. oxygen content
B. pH
C. bicarbonate ion concentration
D. Hb concentration
E. none of the above

5. As blood passes through systemic capillaries, the enzyme carbonic anhydrase catalyzes

A. conversion of dissolved CO2 to carbonic acid
B. conversion of carbonic acid to bicarbonate ion
C. conversion of gaseous CO2 to dissolved CO2
D. binding of carbon dioxide to hemoglobin, thus displacing oxygen
E. all of the above

6. What would be the expected systemic arterial oxygen content of a normal person inhaling pure oxygen (100% O2) for an hour or so?

A. 100 ml O2 / dl blood (100 ml blood)
B. 40 ml O2 / dl blood (100 ml blood)
C. 22 ml O2 / dl blood (100 ml blood)
D. 11 ml O2 / dl blood (100 ml blood)
E. none of the above, since pure oxygen is toxic and would cause death within the hour

7. An oxyhemoglobin saturation of mixed systemic venous blood of 25% for a person at rest is

A. above normal
B. below normal
C. within the normal range

8. A hemoglobin concentration in systemic venous blood of 20 gm/dl blood is

A. above normal
B. below normal
C. within the normal range

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Answer
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[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة]

Smile

Admin عدد المساهمات : 9700 تاريخ التسجيل : 06/08/2009

1. A stroke that destroyed the respiratory center of the medulla would be expected to lead to

A. immediate cessation of breathing
B. apneustic breathing
C. ataxic breathing
D. rapid breathing (hyperpnea)
E. none of the above, since breathing would remain normal

2. The afferent (sensory) endings for the Hering-Breuer reflex are stretch receptors (mechanoreceptors) in the

A. aorta and carotid arteries
B. arteries in the cerebral circulation
C. lungs
D. heart
E. diaphragm and intercostal muscles

3. Stimulation of the reticular activating system of the brainstem (RAS) plays what role in ventilation?

A. stimulates ventilation
B. inhibits ventilation
C. stimulates inhalation but inhibits exhalation (apneustic breathing) D. stimulates exhalation but inhibits inhalation
E. causes ventilation to cease entirely ("Ondine’s Curse")

4. Hyperventilating allows one to hold one’s breath for a longer period of time, because hyperventilation

A. increases the oxygen reserve of systemic arterial blood
B. decreases the PCO2 of systemic arterial blood
C. decreases the pH of systemic arterial blood
D. increases brain blood flow
E. none of the above, since hyperventilation reduces the time one can voluntarily stop breathing

5. The most important afferent (sensory) receptors for the respiratory response to systemic arterial carbon dioxide (Pa-CO2) are the

A. CO2 receptors of the aortic and carotid bodies
B. H+ receptors of the aortic and carotid bodies
C. CO2 receptors in the medulla of the brain
D. H+ receptors in the medulla of the brain
E. CO2 receptors in the airways and lungs

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Answer
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[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة]

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