Airway Anatomy

Question 1

Types of alveoli

Answer 1

Type I - alveolar epithelial cells, main site of gas exchange
Type II - cuboidal epithelial cells with microvilli, secretes alveolar fluid which keeps the surface moist. produces, stores and secretes pulmonary surfactant

Question 2

Respiratory membrane consists of:

Answer 2

alveolar wall: a layer of type I and II cells and macrophages
epithelial basement membrane
capillary basement membrane
endothelial cells of the capillary

Question 3

Surfactant consists of:

Answer 3

phospholipids and lipoproteins

Question 4

Function of surfactant

Answer 4

lower the surface tension of the alevolar fluid, which reduces the tendency of the alveoli to collapse
increases lung compliance and eases the work of breathing

Question 5

Types of respiration

Answer 5

external: exchange of gases between alveoli and blood
internal: exchange of gases between blood and tissue cells

Question 6

partial pressure of O2

Answer 6

alveolar 105mmHg
arterial 100
capillary 40
venous 40

Question 7

partial pressure of CO2

Answer 7

alveolar 40
arterial 40
capillary 45
venous 45

Question 8

Factors that affect diffusion

Answer 8

O2 concentration
altitude
loss of lung tissue
PEEP, CPAP, BIPAP

Question 9

ventilation is regulated by:

Answer 9

a controller within the CNS
a group of effectors
a group of central chemoreceptors
a group of peripheral chemoreceptors
lung receptors

Question 10

Brain centers that control ventilation:

Answer 10

brainstem: medulla and pons

cerebral cortex: voluntary input during behavioural states e.g laughing or crying

Question 11

Effectors are:

Answer 11

the muscles of ventilation that perform the work on command by the controllers within the CNS

Question 12

Central chemoreceptors

Answer 12

respond to changes in hydrogen ion concentration of ECF

ventilation is increased when hydrogen ion concentration increases and vice versa

Question 13

Peripheral chemoreceptors

Answer 13

respond to changes in PaCO2
increase ventilation in response to hypoxia
carotid receptors respond to increase PCO2 and increase ventilation accordingly

Question 14

lung receptors

Answer 14

respond to hyperinflation

send a message via the vagus nerve to the pons and expiration begins

Question 15

Changes in paed airways

Answer 15

large head - flexion of neck, pad under shoulders
large tongue - likelihood of obstruction
high anterior larynx - makes laryngoscopy hard
infant epiglottis long floppy and u shaped
funnel shaped larynx - narrowest at cricoid cartilage
narrow trachea