Respiratory System

Question 1

pulmonary ventilation

Answer 1

movement of gas into and out of the lungs
V = Vt x f
V = DSV + Va
occurs by process known os bulk flow

Question 2

bulk flow

Answer 2

movement of molecules along a passage way due to pressure differences between the two ends of the passageway.

Question 3

Vd

Answer 3

Anatomical dead space: space occupied by the volume of air not participating in gaseous exchange

Question 4

Va

Answer 4

Alveolar ventilation: Air that reaches the respiratory zone

V = Va + Vd

Question 5

typical values for pulmonary ventilation - at rest vs moderate vs intense exercise

Answer 5

REST
BR: 12 Vt: 0.5 V: 6

MOD EXC:
BR: 30 Vt: 2.5 V: 75

INTENSE EXC
BR: 50 Vt: 3 V: 150

Question 6

percentage of gases in air

Answer 6

0. 03% CO2
1. 93% O2
2. 04% N

Question 7

PO2 at sea level

Answer 7

partial pressure of oxygen
= 760 x 0.2093
= 159 mmHg

Question 8

PN2 at sea level

Answer 8

partial pressure of nitrogen
= 760 x 0.7904
= 600.7 mmHg

Question 9

pO2 & pCO2 entering lungs, in alveoli and leaving lungs

Answer 9

Blood entering the lung: 
o	pCO2 ~46 mmHg.
o	pO2 ~40 mmHg
Alveolar gas is approximately: 
o	pCO2  ~40 mmHg
o	pO2 ~105 mmHg 
Blood leaving the lung is approximately:
o	pO2 ~100mmHg 
o	pCO2 ~40 mmHg

Question 10

amount of O2 dissolved in 100mL of plasma

Answer 10

~0.3mL

Question 11

CO2 transport percentage values

Answer 11

9-10% dissolved in plasma
20% combined with Hb - transports as carbamino-haemoglobin
70% transported as H+ and a bicarbonate ion

Question 12

incremental exercise ventilation and pO2

Answer 12

UNTRAINED
Ventilation
o	Linear increase up to ~50–75% VO2 max
o	Exponential increase beyond this point
o	Ventilatory threshold (Tvent)
Inflection point where VE increases exponentially
pO2
o	Maintained within 10–12 mmHg of resting value

ELITE ATHLETE
Ventilation
o	Tvent occurs at higher % VO2 max
pO2
o	Decrease of 30-40mmHH at near-maximal work 
	Hypoxemia
o	Due to: 
	Ventilation/perfusion mismatch
•	Short RBC transit time in pulmonary capillary due to high cardiac output

Question 13

tidal volume (Tv) & avg values

Answer 13

volume inspired or expired per breath

M: 600mL F: 500mL

Question 14

inspiratory reserve volume (IRV) & avg values

Answer 14

max inspiration at end of tidal inspiration

M: 3000mL F: 1900mL

Question 15

expiratory reserve volume (ERV) & avg values

Answer 15

max expiration at end of tidal expiration

M: 1200mL F: 800mL

Question 16

total lung capacity (TLC) & avg values

Answer 16

volume in lungs after max inspiration
TLC = RLV + Vc
M: 6000mL F: 4200mL

Question 17

residual lung volume (RLV) & avg values

Answer 17

volume in lungs after max expiration

M: 1200mL F: 1000mL

Question 18

forced vital capacity (FVC) & avg values

Answer 18

max volume expired after max inspiration
FVC = ERV + Tv + IRV
M: 4800mL F: 3200mL

Question 19

inspiratory capacity (IC) & avg values

Answer 19

max volume inspired following tidal expiration

M: 3600mL F: 2400mL

Question 20

functional residual capacity (FRC) & avg values

Answer 20

volume in lungs after tidal expiration

M: 2400mL F: 1800mL