Ventilation and perfusion at the level of lung

Question 1

Total ventilation

Answer 1

7500 ml/min

Question 2

Anatomic dead space

Answer 2

150 ml

Question 3

Alveolar ventilation

Answer 3

4 L/min

Question 4

Alveolar gas volume

Answer 4

3000 ml

Question 5

Volume of blood in pulmonary capillaries

Answer 5

70 ml

Question 6

Pulmonary blood flow

Answer 6

5000 ml/min

Question 7

What happens if left lung is ventilated but not perfused and right lung is perfused but not ventilated

Answer 7

V/Q = 1 but there is NO GAS EXCHANGE

=> V/Q must be matched at level of alveolar unit for normal gas exchange

Increase perfusion, increase ventilation and vice versa

Question 8

Are all regions of lung ventilated equally

Answer 8

NO

Question 9

Order of zones of lung in terms of decreasing ventilation

Answer 9

1. Lower zone
2. Middle zone
3. Upper zone

Question 10

Normal pulmonary capillary perfusion

Answer 10

5 L/min

Question 11

What is normal V/Q (V/P)

Answer 11

4/5 = 0.8

Question 12

What sort of area is the upper zone

Answer 12

Non-dependent (usually > 1)

Question 13

What sort of area is the lower zone

Answer 13

Dependent area (usually < 1)

Question 14

P and V of alveoli at the apex

Answer 14

Alveoli are UNDERPERFUSED and OVERVENTILATED

Question 15

P and V of alveoli at the base

Answer 15

Alveoli are OVERPERFUSED and UNDERVENTILATED

Question 16

V/P at apex

Answer 16

3.4

Question 17

V/P at base

Answer 17

0.63

Question 18

PO2 at base

PO2 at apex

PO2 difference

Answer 18

89

132

40

Question 19

Difference in ventilation between apex and base

Answer 19

APEX = 0.24 L/min

BASE = 0.82 L/min

Question 20

Difference in blood flow between apex and base

Answer 20

APEX = 0.07 L/min

BASE = 1.29 L/min

Question 21

Consequence of high V/P ratio at apex

Answer 21

high PO2 and low PCO2

(opposite at the base)

Question 22

Relationship between ventilation and perfusion

Answer 22

A local decrease in perfusion matches local decrease in ventilation - diversion of blood flow and air to healthy areas of lungs

Question 23

Blood pH

Formula

What does body buffer to a pH of

Answer 23

7.35 - 7.45

pH = 6.1 + log [HCO3-]/0.03 x [PCO2]

pH = log kidney/lung

Body buffers to a pH of 7.38

Question 24

What is P_aCO2

Answer 24

Partial pressyre of CO2 dissolved in arterial plasma

40 mmHg

Question 25

1. Value for resp acidosis
2. Value for resp alkalosis
3. What will HCO3 be

Answer 25

1. > 45 mmHg
2. < 35 mmHg
3. NORMAL

Question 26

[HCO3-]

Answer 26

22-26 mEq/L

Question 27

1. Value for metabolic acidosis
2. Value for metabolic alkalosis
3. What will P_aCO2 be

Answer 27

1. < 22 mEq
2. > 26 mEq
3. NORMAL