lecture 2

Question 1

define Boyle’s law

Answer 1

the pressure of a gas tends to decrease as the volume of a gas increases

Question 2

each lung is enclosed in how many pleural membranes

Answer 2

2

Question 3

the pleural cavity is filled with what?

Answer 3

intrapleural fluid

Question 4

the visceral pleural membrane coats what?

Answer 4

the outer surface of the lungs

Question 5

the parietal pleural membrane coats what?

Answer 5

the inner surface of the ribs

Question 6

between the visceral pleural membrane and the parietal pleural membrane what will you find?

Answer 6

pleural fluid

Question 7

define pleurisy

Answer 7

inflammation of the pleura

Question 8

describe intrapleural pressure

Answer 8

-3mm subatmospheric

Question 9

what muscles does inspiration use?

Answer 9

external intercostal muscles and the diaphragm

Question 10

expiration is passive at rest but uses what muscles during severe respiratory load?

Answer 10

internal intercostals and adominal muscles

Question 11

apart from the external intercostals and the diaphragm what other muscles are used during inspiration?

Answer 11

sternocleidomastoids

scalenes

Question 12

at rest the diaphragm can be described as contracte or relaxed?

Answer 12

relaxed

Question 13

what is the pathophysiology of asthma

Answer 13

Asthma – over-reactive constriction of bronchial smooth muscle. Increases resistance, expiration difficult.

Question 14

define 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

define Intra-pleural Pressure (Pip):

Answer 15

pressure inside the pleural cavity, ALWAYS negative (in healthy lungs at least!)

Question 16

Transpulmonary pressure (PT):

Answer 16

difference between alveolar pressure and intra-pleural pressure. ALWAYS positive (in health) because Pip is always negative. PT = Palv – Pip.

Question 17

what is the major determinant of airway resistance?

Answer 17

radii of the airways

Question 18

define transpulmonary pressure

Answer 18

is the difference between the alveolar pressure and the intrapleural pressure in the lungs. During human ventilation, air flows because of pressure gradients.