Respiratory Physiology (3)

Question 1

Boyle’s law

Answer 1

states that the pressure exerted by a gas is inversely proportional to to its volume (P a 1/V).
Note that gases (singly or in mixtures) move from areas of high pressure to areas of low pressure.

Question 2

Dalton’s Law

Answer 2

states that the total pressure of a gas mixture is the sum of the pressures of the individual gases.

Question 3

Charles Law

Answer 3

states that the volume occupied by a gas is directly related to the absolute temperature (v a T)

Question 4

Henry’s Law

Answer 4

states that the amount of gas dissolved in a liquid is determined by the pressure of the gas and it’s solubility in the liquid.

Question 5

What direction does gas always move?

Answer 5

High to low pressure

Breath in, decrease pressure in lungs to lower than atmospheric and air moves in. Opposite for expiration

Question 6

When muscles do you use for severe respiratory load (forced expiration)?

Answer 6

Expirationispassiveatrest,butusesinternalintercostal and abdominal muscles during severe respiratory load

Question 7

What muscles are involved in inspiration (up and out movement)?

Answer 7

SCM
SCALENES
EXTERNAL INTERCOSTALS
DIAPHRAGM

Question 8

What muscles are used for forced expiration?

Answer 8

Internal intercostals
Abdominal muscles

Question 9

What is the role of the external intercostal muscles?

Answer 9

Move the rib cage up and outwards

Diagpharm constricts

Expiration

Question 10

What allows for passive expiration?

Answer 10

Elastic recoil of lungs

Can be assisted by the internal meter costal muscles

Question 11

Is there an increase of decrease in resistance during expiration?

Answer 11

Increase

Question 12

When do you notice an asthmatic wheeze?

Answer 12

Expiration

Increased resistance, inflammation and narrowing.

Question 13

Is this inspiration or expiration?

Answer 13

Question 14

When is alveolar pressure negative?

Answer 14

Inspiration

Question 15

Is this inspiration or expiration?

Answer 15

Question 16

What is intra-thoracic pressure? (PA)

Answer 16

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

Question 17

What is intra-pleural pressure? (Pip)

Answer 17

pressure inside the pleural cavity, typically negative compared to atmospheric pressure (in healthy lungs at least!)

Question 18

What is PA and what is Pip?

Answer 18

1. Intra-thoracic (alveolar) pressure (PA)
2. Intra-pleural pressure (Pip)