Physiology 3

Question 1

What causes alveolar ventilation to be less than pulmonary ventilation?

Answer 1

Anatomical dead space

Question 2

What is anatomical dead space dead space?

Answer 2

The remainder of some air in the airways where it is not available for gas exchange.

Question 3

What is the equation for alveolar ventilation?

Answer 3

(Tidal volume-Dead space volume) x Respiratory rate

Question 4

What is the equation for pulmonary ventilation?

Answer 4

Tidal volume x Respiratory rate

Question 5

Define pulmonary ventilation?

Answer 5

The volume of air breathed in and out per minute.

Question 6

Define alveolar ventilation?

Answer 6

The volume of air exchanged between the atmosphere and alveoli per minute.

Question 7

How is pulmonary ventilation increase physiologically?

Answer 7

By increasing depth and rate of breathing

Question 8

Why is increasing depth of breathing more advantageous than increasing respiratory rate?

Answer 8

Due to dead space.

Question 9

What two factors does transfer of gas between body and atmosphere depend on?

Answer 9

Ventilation (V)

Perfusion (Q)

Question 10

What is alveolar dead space?

Answer 10

Ventilated alveoli that are not adequately perfused with blood

Question 11

What is physiological dead space?

Answer 11

The anatomical dead space plus the alveolar dead space.

Question 12

What does accumulation of CO2 in alveoli as a result of increased perfusion do to venitlation

Answer 12

Increases ventilation (Airflow)

Question 13

What does increase in CO2 in alveoli as a result of increased ventilation do to perfusion?

Answer 13

Increases perfusion (Vasodilation)

Question 14

Which 4 factors influence the rate of gas exchange across alveolar membranes?

Answer 14

• Partial pressure gradient of O2 and CO2
• Diffusion coefficient for O2 and CO2
• Surface area of alveolar membrane
• Thickness of alveolar membrane

Question 15

What is Dalton’s law?

Answer 15

Total pressure exerted by a gaseous mixture = the sum of the partial pressure of each individual component in the gas mixture

Question 16

What is partial pressure?

Answer 16

The pressure that one gas in a mixture of gases would exert if it were the only gas present in the whole volume occupied by the mixture at a given temperature

Question 17

What are the units of partial pressure in the UK?

Answer 17

kPa (Kilopascals)

Question 18

In which direction do gases move in terms of pressure?

Answer 18

High to low (Partial pressure gradient)

Question 19

What is the diffusion coefficient?

Answer 19

The solubility of gas in membranes

Question 20

How many times greater is the diffusion coefficient of CO2 than O2

Answer 20

20x

Question 21

What is Fick’s law of diffusion?

Answer 21

The amount of gas that move acroos a sheet of tissue in unit time is proprtional to the area of the tissue but inversely proprtional to it’s thickness.

Question 22

What type of cells make up alveoli walls?

Answer 22

Flattened type I alveolar cells