Topic 3 - Human Gas Exchange [9]

Question 1

During inspiration, what happens to the Lung Volume?

How does air move?

Answer 1

Lung volume increases (to decrease pressure)

Air moves into lungs. High ATM to lower pressure.

Question 2

During inspiration, what happens to the Air pressure in lungs?

Answer 2

initially drops. As air moves in, rises above atmospheric pressure

Question 3

During expiration, what happens to the Air pressure in lungs?

Answer 3

initially greater than ATM. Drops as air moves out.

Question 4

Alveoli have 300 million air sacs in each lung. How is this an adaptation for gas exchange

Answer 4

loads of sacs creates large surface area for gas exchange

Question 5

Alveoli epithelium cells are very thin. How is this an adaptation for gas exchange

Answer 5

short diffusion pathway

Question 6

Alveoli is surrounded by network of capillaries. How is this an adaptation for gas exchange

Answer 6

main concentration gradient as network ‘removes exchanged gases’

Question 7

During inspiration, what happens to the Diaphragm?

Answer 7

Contracts (downwards from domed position.)

Question 8

During expiration, what happens to the Diaphragm?

Answer 8

Relaxes (returns to domed position)

Question 9

During inspiration, what happens to the intercostal muscles?

Internal + External

Answer 9

External - Contract (ribs pulled up and outwards)

Internal - Relax

Question 10

During expiration, what happens to the intercostal muscles?

Answer 10

External - Relax

Internal - Contract (ribs pulled down and inwards)

Question 11

During expiration, what happens to the Lung Volume?

How does air move?

Answer 11

Lung volume decreases (to increase pressure)

Air moves out of lungs. Higher pressure to lower ATM