Respiration and Gas Exchange

Question 1

Primary respiratory muscles

Answer 1

Diaphragm, external intercostal muscles

Question 2

Mechanics of Breathing (inhalation and exhalation)

Answer 2

• Inhalation is always active (result of muscle contraction)
• Exhalation can be active or passive

Question 3

Boyle’s law

Answer 3

Boyle’s law
- Volume of gas varies inversely with pressure at a constant temperature
(As volume increases - gas pressure decreases, as volume decreases - gas pressure increases)

Question 4

What does inspiration begin with?

Answer 4

Contraction of diaphragm

Question 5

Where does air move from and to?

Answer 5

Air moves from areas of high pressure to low pressure

Question 6

Where does gas exchange occur?

Answer 6

Occurs across blood air barrier of alveoli

Question 7

What does pulmonary surfactant do?

Answer 7

(oily secretion)
- Coats alveolar surface and reduces surface tension
- Increases ability of lungs to stretch and expand

Question 8

What two locations in body does gas exchange occur?

Answer 8

Lungs and tissues

Question 9

What happens during gas exchange in lungs?

Answer 9

Oxygen gained, co2 released

Question 10

What happens during gas exchange in tissues?

Answer 10

Oxygen released, co2 gained

Question 11

Dalton’s Law

Answer 11

Each gas contributes to total pressure in proportion to its relative abundance

Question 12

Composition of air

Answer 12

78% nitrogen, 21% oxygen and 1% CO2 and tiny amount other gases