The Pleural Cavity

Question 1

Define tidal volume (TV).

Answer 1

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

Question 2

Define expiratory reserve volume (ERV).

Answer 2

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

Question 3

Define inspiratory reserve volume (IRV).

Answer 3

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

Question 4

Define residual volume (RV).

Answer 4

The volume of gas in the lungs at the end of a maximal inspiration.

Question 5

How can you calculate:
Vital Capacity (VC)?
Total Lung Capacity (TLC)?
Inspiratory Capacity (IC)?
Functional Residual Capacity (FRC)?

Answer 5

VC = TV + IRV + ERV.
TLC = VC + RV = TV + IRV + ERV + RV.
IC = TV + IRV.
FRC = ERV + RV.

Question 6

What is ‘spare’ lung capacity used for?

Answer 6

Periods of greater energy demand.

Question 7

What covers the lungs and the interior of the thorax?

Answer 7

Pleural membranes between the surfaces, of which is a very thin layer of intrapleural fluid.

Question 8

What are the pleura attached to?

Answer 8

Visceral - lung surface; the parietal pleura via cohesive forces of the pleural fluid.
Parietal - the rib cage and diaphragm.

Question 9

Describe the relationship between the pleural membranes and the lungs.

Answer 9

The lungs follow the movements of the bones and muscles of the chest wall during expansion in inspiration.

The chest wall leads the expansion of the lungs. The elastic CT in the lung leads to the recoil of the chest wall in expiration.

Question 10

What is a pneumothorax?

Answer 10

A penetrating wound of the lung.
The lung collapses and the rib cage expands.
The sealed pleural cavity is opened to the atmosphere and air flows in.