McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Biology .
Chapters
| 1. |
Which is CORRECT? |
| A. | voluntary control of breathing originates in the pons/medulla |
| B. | automatic breathing control descends to the respiratory musculature via the corticospinal tract |
| C. | the reciprocal innervation in automatic breathing is via descending pathways rather than spinal reflexes |
| D. | automatic fibres descend to innervate the external intercostal muscles at each thoracic level to mediate expiration |
| E. | there is no output to the phrenic nerves during expiration |
| Answer» C. the reciprocal innervation in automatic breathing is via descending pathways rather than spinal reflexes | |
| 2. |
Which abolishes automatic respiration? Destruction of: |
| A. | pre-Bottzinger complexes |
| B. | ventral gp respiratory neurons |
| C. | dorsal gp respiratory neurons |
| D. | section at the inferior border of the pons |
| E. | transaction rostral to the pons |
| Answer» A. pre-Bottzinger complexes | |
| 3. |
Which does not stimulate carotid bodies? |
| A. | carbon monoxide poisoning |
| B. | cyanide poisoning |
| C. | hypoxia |
| D. | hypercapnia |
| E. | increased H+ concentration |
| Answer» A. carbon monoxide poisoning | |
| 4. |
All of the following shift the Hb dissociation curve to the right during exercise EXCEPT: |
| A. | increased 2,3 DPG |
| B. | increased pCO2 |
| C. | increased temperature |
| D. | decreased pO2 |
| E. | increased H+ concentration |
| Answer» D. decreased pO2 | |
| 5. |
Hypoxia at high altitudes: |
| A. | is a form of stagnant hypoxia |
| B. | causes symptoms of cyanosis |
| C. | causes severe symptoms in an unacclimatised person at 3,000m |
| D. | can always be reversed with 100% O2 |
| E. | increased H+ concentration |
| Answer» B. causes symptoms of cyanosis | |
| 6. |
Regarding surfactant: |
| A. | infant respiratory distress syndrome can be adequately treated with administration of phospholipids alone |
| B. | cigarette smokers have the same amount of surfactant as non-smokers |
| C. | the phospholipid film is formed by tubular myelin |
| D. | infant respiratory distress syndrome is caused by insufficient surfactant that prevents the alveoli from expanding at first inspiratory effort |
| E. | formation of the phospholipid film is greatly facilitated by the carbohydrate in surfactant |
| Answer» C. the phospholipid film is formed by tubular myelin | |
| 7. |
Regarding the work of breathing during quiet inspiration: |
| A. | elastic work = 80% |
| B. | viscous resistance = 7% |
| C. | airway resistance = 13% |
| D. | when tidal volume versus intrapleural pressure in quiet inspiration are plotted, a straight line results |
| E. | the amount of elastic work required to inflate the whole respiratory system is more than the amount required to inflate the lungs alone |
| Answer» B. viscous resistance = 7% | |
| 8. |
Regarding gas exchange in the lungs: |
| A. | PaO2 in pulmonary capillaries is the same as PaO2 in the aorta |
| B. | diffusing capacity for O2 (DLO2) increases from 25→65ml/min/mmHg during exercise |
| C. | DLO2 is unaffected by beryllium poisoning and sarcoidosis |
| D. | CO2 retention is frequently a problem in patients with alveolar fibrosis |
| E. | decreased secretion of PDGF by alveolar macrophages causes pulmonary fibrosis |
| Answer» B. diffusing capacity for O2 (DLO2) increases from 25→65ml/min/mmHg during exercise | |
| 9. |
Regarding gas exchange in the lungs: |
| A. | N2O is diffusion limited |
| B. | CO is perfusion limited |
| C. | O2 is between N2O and CO but at rest, is perfusion limited |
| D. | diffusing capacity of the lung for a gas is inversely proportionate to the surface area of the alveolocapillary membrane and directly proportional to its thickness |
| E. | at rest, it takes blood 0.25secs to traverse the pulmonary capillaries |
| Answer» C. O2 is between N2O and CO but at rest, is perfusion limited | |
| 10. |
Regarding bronchial tone: |
| A. | substance P causes bronchoconstriction |
| B. | constriction is caused by sympathetic discharge |
| C. | dilation is caused by parasympathetic discharge |
| D. | maximal bronchoconstriction occurs at 4am |
| E. | VIP causes bronchoconstriction |
| Answer» A. substance P causes bronchoconstriction | |
| 11. |
Regarding pulmonary function, which of the following is NOT true? |
| A. | FRC = ERV + RV |
| B. | IRV in men is about 3,3L |
| C. | RV in women is about 1.1L |
| D. | inspiratory capacity in men = 4.8L |
| E. | total lung capacity = 6L in men, 4.2L in women |
| Answer» D. inspiratory capacity in men = 4.8L | |
| 12. |
Regarding the glottis: |
| A. | when laryngeal adductors are paralysed there is inspiratory stridor |
| B. | abductors contract early in inspiration |
| C. | when abductors are paralysed, aspiration pneumonia may result |
| D. | the adductors are supplied by the vagus nerves, the abduction by the hypoglossal nerve |
| E. | in animals with bilateral cervical vagotomy, pulmonary oedema is purely secondary to aspiration |
| Answer» B. abductors contract early in inspiration | |
| 13. |
Regarding oxygen transport: |
| A. | Haemoglobin S has glutamic acid instead of valine in the β chains |
| B. | the O2 saturation of Hb is the percentage of available binding sites that do not have O2 attached |
| C. | the oxygenated form of Hb is the T state |
| D. | cyanosis is more obvious in anaemic patients |
| E. | normal P50 is 27mmHg |
| Answer» E. normal P50 is 27mmHg | |
| 14. |
Regarding the O2 dissociation curve: |
| A. | O2 affinity of Hb is reduced when the curve is shifted to the left |
| B. | decreased 2,3-DPG shifts the curve to the right |
| C. | the Bohr effect is attributed to the action of PCO2 on H+ concentration |
| D. | temperature has no effect on the curve |
| E. | 2,3-DPG levels are reduced at altitude |
| Answer» C. the Bohr effect is attributed to the action of PCO2 on H+ concentration | |
| 15. |
Diffusion is inversely proportional to: |
| A. | the diffusion constant |
| B. | tissue area |
| C. | solubility of the gas |
| D. | square root of the molecular weight |
| E. | the difference in partial pressure |
| Answer» D. square root of the molecular weight | |
| 16. |
In exercise: |
| A. | oxygen consumption is about 6L/min in a moderately fit subject |
| B. | the respiratory exchange ratio rises to 0.8 |
| C. | diffusing capacity increases 3-fold |
| D. | the change in cardiac output is only about a sixth of the increase in ventilation |
| E. | the oxygen dissociation curve moves to the left |
| Answer» C. diffusing capacity increases 3-fold | |
| 17. |
Central respiratory chemoreceptors: |
| A. | are located in the medulla near exit of cranial nerve X, XI |
| B. | respond directly to changes in external PCO2 |
| C. | respond directly to changes in arterial PO2 |
| D. | are located on dorsal surface of medulla |
| E. | respond to pH of CSF |
| Answer» E. respond to pH of CSF | |
| 18. |
Respiratory peripheral chemoreceptors: |
| A. | carotid bodies respond to PO2, PCO2, and pH |
| B. | peripheral chemoreceptor response to arterial PCO2 is more important than central chemoreceptor response |
| C. | aortic bodies are located within the aortic valve ring |
| D. | drop in PO2 < 100mmHg causes increase in firing rate |
| E. | carotid bodies respond to venous PO2 |
| Answer» D. drop in PO2 < 100mmHg causes increase in firing rate | |
| 19. |
Ventilatory response to CO2 is reduced by all EXCEPT: |
| A. | sleep |
| B. | barbiturate overdose |
| C. | increasing age |
| D. | decreasing the work of breathing |
| E. | trained athletes and divers |
| Answer» D. decreasing the work of breathing | |
| 20. |
The surface area of the lungs is: |
| A. | three times the area of skin |
| B. | ten times the area of skin |
| C. | 30 times the area of skin |
| D. | 100 times the area of skin |
| E. | none of the above |
| Answer» C. 30 times the area of skin | |
| 21. |
Site of most / major airway resistance is: |
| A. | trachea |
| B. | main bronchi |
| C. | large bronchi |
| D. | medium sized bronchi |
| E. | bronchioles |
| Answer» D. medium sized bronchi | |
| 22. |
The volume of the anatomical dead space is: |
| A. | 50mL |
| B. | 100mL |
| C. | 150mL |
| D. | 200ml |
| E. | 300ml |
| Answer» C. 150mL | |
| 23. |
Which respiratory volume is INCORRECT? |
| A. | tidal volume is the normal breathing volume |
| B. | vital capacity is the volume from maximal inspiration followed by maximal expiration |
| C. | residual volume is the volume remaining in lungs after maximal expiration |
| D. | functional residual capacity is the volume after normal inspiration |
| E. | total lung capacity is the vital capacity plus residual volume |
| Answer» D. functional residual capacity is the volume after normal inspiration | |
| 24. |
The diffusion constant is proportional to: |
| A. | tissue thickness |
| B. | square root of the molecular weight |
| C. | difference in partial pressures |
| D. | tissue area |
| E. | gas solubility |
| Answer» E. gas solubility | |
| 25. |
Mean pressure (mmHg) in the main pulmonary artery is: |
| A. | 2 |
| B. | 5 |
| C. | 8 |
| D. | 15 |
| E. | 25 |
| Answer» D. 15 | |
| 26. |
Regarding pulmonary blood flow: |
| A. | increased arterial pressure leads to increased pulmonary vascular resistance |
| B. | localised vasoconstriction is directly due to arterial PO2 hypoxia |
| C. | regional differences are due to hydrostatic pressure differences |
| D. | at the apex Pa>Pv>PA |
| E. | pulmonary arteries and veins have transmural pressures equal to alveolar pressure |
| Answer» C. regional differences are due to hydrostatic pressure differences | |
| 27. |
Which is not inactivated by the lungs? |
| A. | serotonin |
| B. | bradykinin |
| C. | leukotrienes |
| D. | prostaglandin E2 |
| E. | vasopressin |
| Answer» E. vasopressin | |
| 28. |
Regarding the alveolar gas equation: |
| A. | the respiratory quotient nears 1.0 with exercise |
| B. | PIO2= barometric pressure – water vapour pressure |
| C. | PACO2 > PaCO2 |
| D. | PAO2 is normally 150mmHg |
| E. | remains valid if there is CO2 present in the inspired gas |
| Answer» A. the respiratory quotient nears 1.0 with exercise | |
| 29. |
The amount of O2 in blood with a PaO2 of 100mmHg is: |
| A. | 0.003ml O2/100ml |
| B. | 0.3ml O2/100ml |
| C. | 3ml O2/100ml |
| D. | 3ml O2/mL |
| E. | 0.3ml O2/L |
| Answer» B. 0.3ml O2/100ml | |
| 30. |
Regarding the O2 dissociation curve: |
| A. | increased PCO2 has a direct effect on the curve, shifting it to the right |
| B. | 2,3-DPG levels rise as altitude |
| C. | the deoxy form of Hb is in the relaxed state |
| D. | CO moves the curve to the left as it has 100 times the affinity of O2 for Hb |
| E. | P50 is at a PO2 of 40mmHg |
| Answer» B. 2,3-DPG levels rise as altitude | |
| 31. |
Which respiratory principle is INCORRECT? |
| A. | Fick’s law states that “the volume of gas per unit time that moves across a sheet of tissue is proportional to the area of the sheet, but inversely proportional to its thickness” |
| B. | the Bohr effect is “the effect of PCO2 on the O2 dissociation curve due to the action of PCO2 on H+ concentration” |
| C. | Henry’s law states that “the amount of gas dissolved is proportional to the partial pressure of that gas” |
| D. | the chloride shift is “the diffusion of HCO3 - in to the cell, with the outward diffusion of Cl- ions to maintain electrical neutrality” |
| E. | the Haldane effect is that deoxygenation of the blood increases its ability to carry CO2 |
| Answer» D. the chloride shift is “the diffusion of HCO3 - in to the cell, with the outward diffusion of Cl- ions to maintain electrical neutrality” | |
| 32. |
Given a PCO2 = 600mmHg and a HCO3- = 28mEq/l there is a: |
| A. | metabolic acidosis |
| B. | metabolic acidosis with renal compensation |
| C. | respiratory acidosis |
| D. | respiratory acidosis with renal compensation |
| E. | respiratory alkalosis |
| Answer» C. respiratory acidosis | |
| 33. |
Regarding the elastic properties of the lung: |
| A. | the lung volume at any given pressure during inflation is larger than during deflation |
| B. | the area under the pressure-volume curve is known as the compliance |
| C. | surface tension is the force acting across an imaginary line in the surface of the liquid |
| D. | pressure generated in an alveolus equals 4T/R |
| E. | surfactant, produced by Type I alveolar cells, reduces surface tension in alveoli |
| Answer» C. surface tension is the force acting across an imaginary line in the surface of the liquid | |
| 34. |
Halving the radius of an airway increases resistance: |
| A. | 2-fold |
| B. | 4-fold |
| C. | 8-fold |
| D. | 16-fold |
| E. | has no effect on resistance |
| Answer» D. 16-fold | |
| 35. |
The major site of resistance in the bronchial tree is the: |
| A. | segmental bronchii |
| B. | medium-sized bronchii |
| C. | small bronchii |
| D. | large bronchioles |
| E. | terminal bronchioles |
| Answer» B. medium-sized bronchii | |
| 36. |
Lung compliance increases with: |
| A. | asthma |
| B. | alveolar oedema |
| C. | pulmonary hypertension |
| D. | atelectasis |
| E. | pulmonary fibrosis |
| Answer» A. asthma | |
| 37. |
The ventilatory response to CO2 is increased by: |
| A. | sleep |
| B. | increasing age |
| C. | trained athlete |
| D. | morphine |
| E. | decreased PO2 |
| Answer» E. decreased PO2 | |
| 38. |
Normally the FEV1 is what percentage of FVC? |
| A. | 50% |
| B. | 60% |
| C. | 70% |
| D. | 80% |
| E. | 90% |
| Answer» D. 80% | |
| 39. |
The calibre of extra-alveolar vessels is primarily determined by: |
| A. | the difference between alveolar pressure and the pressure within them |
| B. | the pressure in the pulmonary artery |
| C. | the lung volume |
| D. | the cardiac output |
| E. | the patient’s fluid status |
| Answer» C. the lung volume | |
| 40. |
Which statement regarding hyperbaric oxygen therapy is INCORRECT? |
| A. | males eliminate carboxy haemoglobin faster than females |
| B. | gas around the body is normal air compressed to the same high pressure |
| C. | it produces marked increases in dissolved oxygen in the blood |
| D. | oxygen is administered at up to 3 atmospheres pressure |
| E. | toxicity includes optic neuritis |
| Answer» A. males eliminate carboxy haemoglobin faster than females | |
| 41. |
All of the following are features of acclimatisation to high altitude EXCEPT: |
| A. | shift to the right of the oxygen dissociation curve |
| B. | increased number of capillaries in peripheral tissues |
| C. | pulmonary vasodilation |
| D. | polycythaemia |
| E. | increased maximum breathing capacity |
| Answer» C. pulmonary vasodilation | |
| 42. |
Which of the following statements is TRUE? |
| A. | pulmonary stretch receptors lie within the airway epithelial cells |
| B. | J receptors, when stimulated, cause slow deep breathing |
| C. | irritant receptors, when stimulated, send impulses up the vagus in unmyelinated fibres |
| D. | irritant receptors are rapidly adapting |
| E. | increased maximum breathing capacity |
| Answer» D. irritant receptors are rapidly adapting | |
| 43. |
Which one of the following statements regarding ventilation is INCORRECT? |
| A. | tidal volume in the average human is 500ml |
| B. | anatomical dead space is the volume of the conducting airway and is about 160ml |
| C. | upper regions of the lung ventilate better than the lower regions |
| D. | you can measure physiological dead space via Bohr’s method to get what is called a Bohr equation which is: VD PACO2-PECO2 VT PACO2 |
| E. | None of the above |
| Answer» C. upper regions of the lung ventilate better than the lower regions | |
| 44. |
The diffusion capacity (DI) of the lung accounts for: |
| A. | P1-P2 |
| B. | area of lung |
| C. | the thickness |
| D. | diffusion constant |
| E. | all of the above |
| Answer» A. P1-P2 | |
| 45. |
Regarding movement to high altitude, which statement is INCORRECT? |
| A. | hyperventilation occurs due to hypoxic stimulation of peripheral chemoreceptors |
| B. | pro-erythroblasts mature into erythrocytes more rapidly than normal |
| C. | renal bicarbonate excretion increases |
| D. | increased numbers of mitochondria appear in the tissues |
| E. | FiO2 decreases with increasing altitude |
| Answer» E. FiO2 decreases with increasing altitude | |
| 46. |
Metabolic functions of the lung include all of the following EXCEPT: |
| A. | conversion of AI to AII by ACE |
| B. | metabolism of AII |
| C. | inactivation of bradykinin |
| D. | removal of serotonin |
| E. | metabolism of arachidonic acid metabolises |
| Answer» B. metabolism of AII | |
| 47. |
Which of the following is INCORRECT? |
| A. | O2 toxicity causes convulsion |
| B. | O2 at 100% in premature infants causes retrolental fibroplasia |
| C. | acclimatisation to high altitudes include a shift to the left of the O2 dissociation curve |
| D. | polycythaemia is a feature of acclimatisation |
| E. | acute mountain sickness is due to hypoxaemia and alkalosis |
| Answer» C. acclimatisation to high altitudes include a shift to the left of the O2 dissociation curve | |
| 48. |
Regarding the neural control of breathing, which statement is INCORRECT? |
| A. | medullary centres are close to but separate from central chemoreceptors |
| B. | during quiet respiration, expiration is a passive event |
| C. | inspiratory medullary neurons supply both phrenic nerves |
| D. | ventral medullary neurons are expiratory and do not discharge spontaneously |
| E. | inspiratory medullary neurons discharge spontaneously at a rate of 12-15 times/minute |
| Answer» D. ventral medullary neurons are expiratory and do not discharge spontaneously | |
| 49. |
The transport of which of the following gases is DIFFUSION LIMITED? |
| A. | O2 |
| B. | N2O |
| C. | CO2 |
| D. | CO |
| E. | halothane |
| Answer» D. CO | |
| 50. |
With regard to anatomic dead space, all of the following are true EXCEPT: |
| A. | it is calculated by Bohr’s method |
| B. | the normal value is about 150ml |
| C. | it increases with large inspirations |
| D. | depends on the size of the subject |
| E. | it is equivalent to the conducting zone |
| Answer» A. it is calculated by Bohr’s method | |
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