6.7 - The Mechanisms Of Breathing

Question 1

Define ventilation

Answer 1

Scientific term for breathing - where air is constantly moving in and out of the lungs

Question 2

Define inspiration

Answer 2

Also known as inhalation - occurs when air pressure in the atmosphere is greater than that of the lungs; forcing air into the alveoli

Question 3

Define expiration

Answer 3

Also known as exhalation - occurs when air pressure in the lungs is greater than that in the atmosphere; forcing air out of the alveoli

Question 4

In inspiration, which muscles contract (2) and which muscles relax (1)

Answer 4

CONTRACT :
- external intercostal muscles
- diaphragm

RELAX:
- internal intercostal muscles

Question 5

In expiration which muscles contract (1) and which muscles relax (2)

Answer 5

CONTRACT:
- internal intercostal muscles

RELAX:
- external intercostal muscles
- diaphragm

Question 6

What happens to the air pressure in the lungs during inspiration and expiration?

Answer 6

• During inspiration the air pressure decreases
• During expiration the air pressure increases

Question 7

What happens to lung volume during inspiration and expiration?

Answer 7

• During inspiration the lung volume increases
• During expiration the lung volume decreases

Question 8

What is tidal volume?
What is this usually?

Answer 8

• The volume of air normal taken at each breath when the body is at rest.
• This is usually around 0.5 dm cubed

Question 9

What is ventilation rate?
What is this usually?

Answer 9

• The number of breaths taken in one minute
• Normally 12-20 in a healthy adult

Question 10

What is the pulmonary ventilation equation?

Answer 10

Pulmonary ventilation = tidal volume x ventilation rate

Question 11

What is the diaphragm?

Answer 11

A sheet of muscle that separates the thorax from the abdomen

Question 12

What are the intercostal muscles ?

Answer 12

These are the muscles between the ribs that allow for the expansion/compression of the thoracic cavity