Chapter 2

Question 1

Number of alveoli per lung?

Answer 1

300 million - diameter 100-300 micrometer

Question 2

Number of capillaries per alveolus?

Answer 2

1000

Question 3

What produces bronchodilatation and bronchoconstriction?

Answer 3

Smooth muscle cells contained in the walls of the airways can contribute largely to airway resistance and are regulated by the autonomic nerve system:
- adrenergic sympathetic fibres producing bronchodilatation
- cholinegis parasympathetic fibres producing bronchoconstriction

Question 4

What is transpulmonary pressure?

Answer 4

Difference between alveolar pressure (= atmospheric pressure) and intrapleural pressure: Ptp = Palv - Pip

Question 5

How much negative pressure is created during normal inspiration?

Answer 5

-4 mmHg

Question 6

Normal lung compliance?

Answer 6

100 mL/cm H2O

Question 7

What is surfactant?

Answer 7

Surface-active lipoprotein complex (phospholipoprotein) formed by Type II alveolar cells with hydrophilic head and hydrophobic tail regions.

Question 8

What produces surfactant?

Answer 8

Type II alveolar cells

Question 9

Laplace’s law?

Answer 9

P = T/r (concentration of surfactant is higher in small alveoli)

Question 10

Volume of anatomical dead space?

Answer 10

150 mL

Question 11

Physiological dead space?

Answer 11

Alveoli that are well ventilated but poorly perfused

Question 12

V/Q ratio normal

Answer 12

0.8 (ventilation 4M/min, pulm blood flow 5L/min)

Question 13

Physiological shunt?

Answer 13

Blood from bronchial vessels do not partake in pulmonary gas exchange but does enter left atrium

Question 14

What is Fick’s law of diffusion?

Answer 14

• Rate of gas transfer is proportional to surface area and partial pressure of gas across the two sides, and inversely proportional to the thickness of the tissue:

R=(DxAxdeltaP)/d

Question 15

Which has higher solubility: CO2 or O2?

Answer 15

CO2: 20 times more rapidly

Question 16

Three anatomical layers of alveolar cavity

Answer 16

• Continuous cytoplasmic tube of endothelial cells
• Connective tissue
• Alveolar cellur wall

Question 17

Respiratory exchange ratio?

Answer 17

Ratio of CO2 release to O2 uptake

Question 18

What are the West zones?

Answer 18

PA = alveolar pressure; Pa: arterial pressure: Pv: venous pressure
Zone 1 (upper): PA -> Pa > PV (does not exist in healthy individuals but does exist with positive pressure ventilation)
Zone 2 (middle): Pa > PA > PV
Zone 3 (lower): Pa > PV > PA

Question 19

Expected alveolar-arterial PO2 gradient

Answer 19

A-a PO2 gradient = Age/4 + 4

Question 20

Stages of pulmonary edema

Answer 20

Stage 1: increase in lymphatic drainage
Stage 2: fluid around bronchioles
Stage 3: flulid in less compliant compartments of interstitial space

Question 21

Bohr effect

Answer 21

Release of O2 when pH decreases or PaCO2 increases, even if PaO2 is relatively high