Chapter: Respiration
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
51.

Which of the following is INCORRECT?

A. haemoglobin S causes the O2 curve to shift to the left
B. the O2 dissociation curve is shifted to the right by an increased PCO2, H+ concentration and temperature
C. carboxy haemoglobin has 240 times the affinity of O2 for Hb
D. COHB shift the O2 dissociation over to the left
E. it is equivalent to the conducting zone
Answer» A. haemoglobin S causes the O2 curve to shift to the left
52.

Regarding the chemical control of breathing, which statement is INCORRECT?

A. central chemoreceptors are located in the medulla oblongata
B. hypoxia makes an individual more sensitive to increases in arterial carbon dioxide
C. arterial oxygen less than 70mmHg markedly stimulates respiration via the carotid bodies
D. carotid bodies have the highest blood flow, per unit time per 100g, of any tissue in the body
E. carbon dioxide is more important than oxygen in respiratory control
Answer» C. arterial oxygen less than 70mmHg markedly stimulates respiration via the carotid bodies
53.

Fick’s law states that:

A. Va = (VCO2/PCO2) x K
B. V = (A.D.(P1 – P2))/T
C. pH - -LOG[H+]
D. P1V1 = P2V2
E. V1/V2 = T1/2
Answer» B. V = (A.D.(P1 – P2))/T
54.

Regarding surfactant, which statement is INCORRECT?

A. it predominantly consists of phospholipid
B. it is increased by long-term 100% oxygen therapy
C. hydrophobic “tails” face into alveolar lumen
D. it is decreased by cigarette smoking
E. pulmonary oedema is a consequence of its absence
Answer» B. it is increased by long-term 100% oxygen therapy
55.

Which of the following DOES NOT shift the O2 dissociation curve to the right?

A. increased temperature
B. increased PCO2
C. increased H+
D. increased DPG
E. increased carboxy haemoglobin
Answer» E. increased carboxy haemoglobin
56.

Regarding exercise, which statement is INCORRECT?

A. the energy cost of breathing is up to 10% of total energy expenditure
B. total pulmonary ventilation increases by up to 20 fold
C. total oxygen consumption increases by up to 20 fold
D. total carbon dioxide production increases by up to 40 fold
E. P5O increases
Answer» A. the energy cost of breathing is up to 10% of total energy expenditure
57.

Total lung capacity is equal to:

A. vital capacity + tidal volume
B. vital capacity + functional residual capacity
C. tidal volume + residual volume
D. functional residual capacity + tidal volume
E. vital capacity + residual volume
Answer» E. vital capacity + residual volume
58.

Regarding compliance, which statement is INCORRECT?

A. functional residual capacity is the equilibrium volume when elastic recoil of lung is balanced by normal tendency for chest wall to spring out
B. hysteresis is due to frictional resistance to air movement
C. compliance is greater in expiration than in inspiration
D. compliance is increased in emphysema
E. compliance is a dynamic measure of lung and chest wall recoil
Answer» E. compliance is a dynamic measure of lung and chest wall recoil
59.

Which of the following is NOT involved in the control of ventilation?

A. peripheral chemoreceptors
B. lung stretch receptors
C. basal ganglia
D. pons
E. respiratory muscles
Answer» C. basal ganglia
60.

Which of the following DOES NOT decrease lung compliance?

A. left ventricular failure
B. atelectasis
C. pulmonary fibrosis
D. advancing age
E. raised pulmonary capillary wedge pressure
Answer» D. advancing age
61.

Regarding ventilation / perfusion (V/Q) relationships, which statement is INCORRECT?

A. V/Q ratio is greatest at the lung apex
B. V/Q ratio is about one at level of third rib when upright
C. ventilation decreases proportionately more than perfusion from base to apex
D. V/Q ratio for whole lung at rest is about 0.8
E. exercise increases the V/Q ratio
Answer» C. ventilation decreases proportionately more than perfusion from base to apex
62.

Regarding pulmonary perfusion, which statement is INCORRECT?

A. apical perfusion is less than basal
B. E.coli endotoxin causes venodilatation
C. total pulmonary blood flow increases 3-6 fold during exercise
D. pulmonary vascular resistance increases at small lung volumes
E. in zone 2, pulmonary arterial pressure is greater than alveolar pressure
Answer» B. E.coli endotoxin causes venodilatation
63.

Regarding pulmonary ventilation, which statement is INCORRECT?

A. physiological dead space is normally larger than anatomical dead space
B. basal ventilation is greater than apical
C. normal tide volume is about 7ml/kg
D. airway resistance decreases at large lung volumes
E. total pulmonary ventilation can increase by up to 20 fold during exercise
Answer» A. physiological dead space is normally larger than anatomical dead space
64.

Which of the following DOES NOT constrict pulmonary arterioles?

A. adrenaline
B. thromboxane B2
C. noradrenaline
D. prostaglandin F2 α
E. isoproteronol
Answer» E. isoproteronol
65.

Regarding the lung volumes in a healthy 70kg male, 183cm tall, which is INCORRECT?

A. tidal volume = 500ml
B. residual volume = 1200ml
C. expiratory reserve volume = 1000ml
D. inspiratory capacity = 3300ml
E. vital capacity = 4800ml
Answer» D. inspiratory capacity = 3300ml
66.

Regarding carbon dioxide transport in blood, which statement is INCORRECT?

A. oxygen is about 20 times less soluble in blood
B. deoxygenation of blood increase its ability to carry carbon dioxide
C. arterial blood transports about 20% in dissolved form
D. venous blood has higher haematocrit than arterial blood
E. carbamino compounds are formed by reaction with both plasma proteins and Hb
Answer» C. arterial blood transports about 20% in dissolved form
67.

Which of the following does NOT increases synthesis of 2, 3-DPG?

A. growth hormone
B. phosphate deficiency
C. thyroid hormone
D. exercise for one hour
E. androgens
Answer» B. phosphate deficiency
68.

Which of the following DOES NOT shift the oxygen-haemoglobin dissociation curve to the right?

A. decreased phosphate
B. increased altitude
C. cortisol
D. decreased pH
E. aldosterone
Answer» A. decreased phosphate
69.

Regarding alveolar cells, which statement is INCORRECT?

A. type I pneumocytes repair alveolar epithelium
B. pulmonary alveolar macrophages are derived from blood monocytes
C. mast cell membranes bind IgE via Fc portion to heavy chain
D. APUD (neuroendocrine) cells are of endodermal origin
E. type II pneumocytes are membranous
Answer» E. type II pneumocytes are membranous
70.

Which of the following substances is NOT removed from the blood by the lung?

A. prostaglandins
B. noradrenaline
C. acetylcholine
D. adrenaline
E. bradykinin
Answer» D. adrenaline
71.

Which statement regarding gas exchange in the lungs is INCORRECT?

A. gases generally cross by simple diffusion
B. diffusion capacity for carbon dioxide is much greater than for oxygen
C. nitrous oxide is a diffusion limited gas
D. carbon monoxide does not reach equilibrium in 0.75 seconds
E. oxygen is a perfusion limited gas
Answer» C. nitrous oxide is a diffusion limited gas
72.

Which of the following substances is NOT synthesised by the lung?

A. prostaglandins
B. serotonin
C. dipalmityl phosphatidylcholine
D. histamine
E. kallikrein
Answer» B. serotonin
73.

Exercise has all of the following effects on blood gases EXCEPT:

A. increased PACO2
B. increased PAO2
C. unchanged PaCO2
D. unchanged PaO2
E. increased PvCO2
Answer» A. increased PACO2
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