Ventilation and Compliance

Question 1

What is the average volume for anatomical dead space?

Answer 1

150ml

Question 2

What is TV - Tidal Volume

Answer 2

The volume of air breathed in and out of the lungs at each breath

Question 3

What is ERV - Expiratory Reserve Volume

Answer 3

The maximum volume of air which can be expelled from the lungs at the end of a normal expiration

Question 4

What is IRV - Inspiratory Reserve Volume

Answer 4

The maximum volume of air which can be drawn into the lungs at the end of normal inspiration

Question 5

What is RV - Residual Volume

Answer 5

The volume of gas in the lungs at the end of a maximal expiration

Question 6

What is VC - Vital capacity

Answer 6

Vital capacity = tidal volume + inspiratory reserve voume + expiratory reserve volume

Question 7

What is TLC - Total lung capacity

Answer 7

Total Lung Capacity = vital capacity + inspiratory reserve volume

Question 8

What is IC - Inspiratory Capacity

Answer 8

Inspiratory Capacity = tidal volume + inspiratory reserve volume

Question 9

What is FRC - Functional Residual Capacity

Answer 9

Functional residual capacity = expiratory reserve volume + residual volume

Question 10

What is Pulmonary ventilation?

Answer 10

The total air movement into/out of lungs (relatively insignificant in functional terms)

Measured in L/min

Question 11

What is Alveolar ventilation?

Answer 11

Fresh air getting to alveoli and therefore available for gas exchange (functionally much more significant)

Measured in L/min

Question 12

What is Partial Pressure?

Answer 12

The pressure of a gas in a mixture of gases is equivalent to the percentage of that particular gas in the entire mixture multiplied by the pressure of the whole gaseous mixture.

Pressure is commonly expressed in mmHg or kPa units

Question 13

Alveolar walls are made up of what 2 cell types?

Answer 13

Thin walled ‘Type 1’ cells which permit gas exchange

Specialised ‘Type 2’ cells which secrete surfactant fluid

Question 14

What do Type 2 alveolar cells produce?

Answer 14

Surfactany, a detergent like fluid which reduces surface tension on alveolar surface membrane, thus reducing tendency for alveoli to collapse.

Question 15

What is Compliance?

Answer 15

The change in volume relative to change in pressure

i.e. how much does volume change for any given change in pressure.

It represents the stretchability of the lungs (not the elasticity)

Changes in disease states/age

Question 16

High compliance = what?

Answer 16

Large increased in lung volume for small decreased in ip pressure

Question 17

Low compliance = what?

Answer 17

small increase in lung volume for large decrease in ip pressure.

Question 18

What does Emphysema do?

Answer 18

Loss of elastic tissue means expiration requires effort

Question 19

What does Fibrosis do?

Answer 19

Inert fibrous tissue means effort of inspiration increases

Question 20

An obstructive lung diease does what?

Answer 20

Obstruction of air flow, especially on expiration

Question 21

A Restrictive lung disease does what?

Answer 21

Restricts the expansion of the lungs

Question 22

What is spirometry?

Answer 22

A technique used to measure lung function. Measurements can be classed as static or dynamic.

Static - Where the only consideration made is the volume exhaled.

Dynamic - where the time taken to exhale a certain volume is what is being measured.

Question 23

What volumes can be measured directly using spirometry?

Answer 23

Tidal volume
Expiratory reserve volume
Inspiratory reserve volume
Inspiratory capacity
Vital capacity

Question 24

How is respiration affected in an obstructive lung disease like COPD?

Answer 24

Rate at which air is exhaled is much slower

Total volume is also reduced

Question 25

How is respiration affected in a restrictive lung disease like Pulmonary fibrosis?

Answer 25

Absolute rate of airflow is reduced

Total volume is reduced due to limitations to lung expansion