Mechanics of breathing.

Question 1

Breathing is under (what control)?
Breathing is affected by two processes which are?

Answer 1

Breathing is under autonomic control.
Autonomic Control = You do not need to consciously think about it as it’s automatic.
1) Inhalation/inspiration. 2) Exhalation/Expiration.

Question 2

Describe inhalation/inspiration (4 steps)

Answer 2

1) Diaphragm contract/flattens.
2) Intercostal muscles (between the ribs) contract and move the ribs upwards/outwards.
3) Increase in volume of thoracic cavity thereby cavity pressure decreases.
4) This causes air to rush into the lungs as pressure is lower than in the thoracic cavity.

Question 3

Describe exhalation/inhalation (4 steps).

Answer 3

1) Diaphragm relaxes and curves upwards.
2) Intercostal muscles relax, ribs move down/in.
3) This decreases the volume of the thoracic cavity thereby increasing the pressure.
4) Air rushes out of the lungs, as thoracic cavity has more pressure than atmospheric pressure.

Question 4

1) What is tidal volume?
2) What is inspiratory reserve?
3) What is expiratory reserve?

Answer 4

1) The volume of gas inspired-expired in a normal breathing cycle.
2) The max volume of gas that’s inspired after normal inspiration.
3) The max gas volume expired in usual expiration.

Question 5

4) What is residual volume?
5) What is vital capacity?

Answer 5

1) Gas volume after maximum expiration.
2) Max expirable gas after max inspiration.