Respiratory Physiology 2

Question 1

Define TIDAL VOLUME

Answer 1

The volume of air you breathe in and the volume of air you breathe out at rest (~ half capacity)

Question 2

Define INSPIRATORY RESERVE VOLUME

Answer 2

The maximum volume of air which can be drawn into the lungs at the end of a normal inspiration.

Question 3

Define EXPIRATOY RESERVE VOLUME

Answer 3

The maximum volume of air which can be expelled from the lungs at the end of a normal expiration.

Question 4

Define VITAL CAPACITY

Answer 4

Maximum amount of air that can be expired after a maximum inspiration

Question 5

Define RESIDUAL VOLUME

Answer 5

The volume of gas in the lungs at the end of a maximal expiration

Question 6

What is covered by PLEURAL MEMBRANES?

Answer 6

The lungs and interior of the thorax

Question 7

VISCERAL PLEURAL MEMBRANE

Answer 7

Lines the outer surface of the lungs

Question 8

PARIETAL PLEURAL MEMBRANE

Answer 8

Lines inner surface of the ribs

Question 9

How are lungs stuck to the rib cage?

Answer 9

Through the relationship of the pleural membranes

Question 10

How is recoil of the chest wall in normal expiration brought about?

Answer 10

Recoil of the elastic connective tissue in the lung

Question 11

What is the relationship between Boyle’s law and the mechanics of breathing?

Answer 11

Increased volume = decreased pressure
Decreased volume = increased pressure

Question 12

How does INSPIRATION happen?

Answer 12

Use of external intercostals muscles and the diaphragm

Question 13

EXPIRATION is passive at rest, however during severe respiratory load what does it use?

Answer 13

uses internal intercostal and abdominal muscles

Question 14

What is INTRA-THORACIC (Alveolar) PRESSURE (PA)

Answer 14

Pressure inside the thoracic cavity, (essentially pressure inside the lungs).
May be negative or positive compared to atmospheric pressure

Question 15

What is INTRA-PLEURAL PRESSURE (Pip)

Answer 15

Pressure inside the pleural cavity, typically negative compared to atmospheric pressure

Question 16

What is TRANSPULMONARY PRESSURE (PT)

Answer 16

Difference between alveolar pressure and intra-pleural pressure.
Almost always positive because Pip is negative

Question 17

What are the 2 cell types that make up the alveolar wall?

Answer 17

• Thin walled “Type I” cells which permit gas exchange
• Specialised “Type II” cells which secrete surfactant fluid

Question 18

What is the purpose of SURFACTANT?

Answer 18

Reduces surface tension on alveolar surface membrane

Question 19

When does surface tension occur?

Answer 19

where ever there is an air-water interface and refers to the attraction between water molecules

Question 20

When is SURFACTANT more effective?

Answer 20

In small alveoli than large alveoli because surfactant molecules come closer together and are therefore more concentrated.

Question 21

What does SURFACTANT prevent?

Answer 21

Alveolar collapse

Question 22

Define COMPLIANCE

Answer 22

Change in volume relative to change in pressure
It represents the stretchability of the lungs (not the elasticity!)

Question 23

HIGH COMPLIANCE =

Answer 23

large increase in lung volume for small decrease in ip pressure

Question 24

LOW COMPLIANCE =

Answer 24

small increase in lung volume for large decrease in ip pressure

Question 25

What is between the surfaces of the pleural membranes

Answer 25

An extremely thin layer of intrapleural fluid.