6.7 Breathing and 6.8 Exchange of gases in lungs

Question 1

What is inspiration?

Answer 1

When the air pressure of the atmosphere is greater then the air pressure inside the lungs, air is forced into the lungs.

Question 2

What is expiration?

Answer 2

When the air pressure in the lungs is greater in than that of the atmosphere, air is forced out.

Question 3

Function of internal intercostal muscles?

Answer 3

Contractions leads to expiration.

Question 4

Functions of external intercostal muscles?

Answer 4

Contractions lead to inspiration.

Question 5

What muscles/ribs/ diaphragm contract/ relax in inspiration?

Answer 5

External intercostal muscles contract, internal intercostal muscles relax, ribs are pulled upwards and outwards, diaphragm muscles contract causes ur to flatten.

Question 6

Muscles/ribs/ diaphragm contract/ relax in expiration?

Answer 6

Internal intercostal muscles contract, external muscles relax, ribs move downwards and inwards, diaphragm muscles relax, pushed up against abdomen.

Question 7

Describe in terms of pressure and volume how we breath in?

Answer 7

Ribs- increase volume of thorax/ diaphragm- increase volume of thorax
Increased volume of thorax=decrease of pressure of lungs.
Atmospheric pressure is greater then pulmonary pressure and air is forced into lungs.

Question 8

Explain how to calculate pulmonary ventilation?

Answer 8

Pulmonary ventilation rate (dm3min-1) = tidal volume (dm3) x breathing rate (min-1)

Question 9

Use ficks law to explain how alveoli are adapted for gas exchange?

Answer 9

300 million alveoli in each lung. Increases SA, SA is around 70m2. Lined with thin epithelial cells. Small diffusion distance, network of pulmonary capillaries surrounding each alveoli maintains concentration gradient

Question 10

3 risk factors that can lead to lung disease?

Answer 10

Smoking, air pollution, genetic make up and occupation.