Physiology - Respiratory - Cairns (1) Flashcards
Which one of the following is an accessory muscle of inspiration?
a) External oblique
b) Internal oblique
c) Alae nasi
d) External intercostals
e) Rectus abdominus
I think it’s C (see West’s p.97), but Cairns says its D.
During quiet breathing, the diaphragm is responsible for what percentage of change in intrathoracic volume?
a) 10%
b) 25%
c) 50%
d) 75%
e) 100%
D
The normal residual volume in an adult male is
a) 500mL
b) 800mL
c) 1200mL
d) 1800mL
e) 2300mL
C
Which of the following is a cause of reduced lung compliance?
a) Aging
b) Emphysema
c) Atelectasis
d) Asthma
e) Pneumothorax
C
Which of the following is a function of surfactant?
a) Reduces lung compliance
b) Reduces alveolar stability
c) Maintains dry alveoli
d) Decreases residual volume
e) Activates macrophages
C. It prevents pulmonary oedema.
Regarding dead space
a) Anatomical dead space is always greater than physiological dead space
b) Dead space of an adult male is approximately 350mL
c) Physiological dead space can be measured using Fowler’s method
d) Dead space can be calculated if the tidal volume, alveolar PCO2, and expiratory air PCO2 are known.
e) Dead space usually decreases in lung disease
D
Uptake of which of the following is perfusion limited?
a) Oxygen
b) Carbon dioxide
c) Carbon monoxide
d) Methoxyflurane (Penthrane)
e) Enflurane
A
Oxygen diffusion capacity of the alveolocapillary membrane is reduced by all of the following EXCEPT:
a) Altitude
b) Lung fibrosis
c) Atelectasis
d) Infection
e) Diving
E
The volume of blood in the pulmonary vasculature is
a) 500mL
b) 1000mL
c) 1500mL
d) 2000mL
e) 2500mL
B. The volume in the pulmonary vasculature is less than in the systemic vasculature because the systemic vasculature includes systemic veins that act as blood reservoirs. (? .. Not so sure about it being as low as 1000mL… ? )
Pulmonary vascular resistance is what proportion of systemic resistance?
a) One tenth
b) One sixth
c) One half
d) Identical
e) Twice
A. See West’s p.40. It is the MAP that is one-sixth, not the vascular resistance.
Marked pulmonary vasoconstriction occurs when alveolar pO2 falls below:
a) 300mmHg
b) 150mmHg
c) 100mmHg
d) 70mmHg
e) 25mmHg
D
Regarding water balance in the lung:
a) Fluid in the alveolar space is actively transported into the interstitium
b) Net flow is usually directed towards the capillary
c) Increased capillary pressure results in flow into the alveoli in the first instance
d) Pulmonary lymphatics are poorly developed
e) Peribronchial thickening only occurs in severe acute pulmonary oedema
A. Peribronchial thickening occurs in early pulmonary oedema. The pulmonary lymphatics are very numerous and active. Fluid that reaches the alveolar spaces is actively pumped out by a sodium-potassium ATPase pump in epithelial cells.
All of the following hormonal agents cause pulmonary vasodilation EXCEPT:
a) Adenosine
b) Angiotensin II
c) ANP
d) Vasopressin
e) Endothelin
B
The most likely fate of an inspired particle 5um in diameter is:
a) Removal by nasal hairs
b) Settles on tonsillar area
c) Settles on mucous membrane of trachea
d) Deposits in alveolus
e) Exhaled
C. Only the smallest particles (less than 0.1um in diameter) reach the alveoli. Many small particles are not deposited at all but are exhaled with the next breath.
One gram of haemoglobin contains approximately how much oxygen?
a) 0.01mL
b) 0.14mL
c) 1.4mL
d) 14.4mL
e) 140mL
C. West’s says 1.39mL.
