4b. Gas exchange, Ventilation and Respiratory Volumes/Capacities

Question 1

structure of alveolus

Answer 1

Lined by simple squamous epithelium and supported by thin elastic basement membrane

Question 2

describe type I pneumocyte

Answer 2

simple squamous epithelial cells, site of gas exchange

Question 3

describe type II pneumocyte

Answer 3

simple cuboidal cells, secrete alveolar fluid and surfactant

Question 4

5 characteristics of respiratory membranes

Answer 4

The thickness of the membrane
surface area
diffusion coefficent
Partial pressure
moist membranes

Question 5

how does oxygen travel in blood

Answer 5

Red blood cells (haemoglobin) 98.5%
Dissolved in blood plasma 1.5%

Question 6

how does CO2 travel in blood

Answer 6

HC03 dissolved in plasma 70%
CO2 dissolved in plasma 7%
Bound to Haemoglobin 23%

Question 7

what is pulmonary ventilation?

Answer 7

Process of moving air into and out of the lungs

Question 8

list 2 functions of pulmonary ventilation

Answer 8

Prevents build up of CO2 in blood
supplies tissues with O2

Question 9

what muscles are involved in quiet breathing?

Answer 9

diaphragm
external intercostals
Relaxation of inspiratory muscles
Elastic recoil of lungs, surface tension

Question 10

what is Boyle’s law?

Answer 10

volume is inversely proportional to pressure

Question 11

4 results of inspiration

Answer 11

Lung volume increases
Intra alveolar pressure decreases
Barometric pressure > intra alveolar pressure
Air rushes in, equalises pressure

Question 12

4 results of expiration

Answer 12

Lungs: volume decreases
Intra alveolar pressure increases
Intra alveolar pressure > barometric pressure
Air rushes out

Question 13

describe tidal pressure

Answer 13

the amount of air inspired and expired with each breath

Question 14

describe Inspiratory reserve volume

Answer 14

the amount of air that can be inspired forcefully after inspiration of the tidal volume

Question 15

describe Expiratory reserve volume

Answer 15

the amount of air that can be forcefully expired after expiration of the tidal volume

Question 16

describe Residual volume

Answer 16

the volume of air remaining in the respiratory passages and lungs after the most forceful expiration

Question 17

what is total lung capacity?

Answer 17

Inspiratory reserve volume + expiratory reserve volume + tidal volume + residual volume

Question 18

what are two numerical indicators of an obstructed and restricted airway

Answer 18

FEV 1 sec
FVC