Lecture 18 - Lung Development and Surfactant

Question 1

Embryonic period events?

Answer 1

Day 26 - wk7: ventral outpouching, series of branching forming lung bud up to segmental bronchi

Question 2

Embryonic period risks?

Answer 2

fistula

Question 3

Pseudoglandular Period Events?

Answer 3

5-17wk: continues branching up to terminal bronchioles

Question 4

Canalicular period events?

Answer 4

16-25wk: alveolar duct formation,

Question 5

Saccular Period Events?

Answer 5

24wk-postnatal: type II alveolar cells formed and produce surfactant

Question 6

Alveolar phase?

Answer 6

Late fetal -> 8yr: alveolar maturation and lining formation

Question 7

Hydrophilic surfactant proteins?

Answer 7

SP-A (reduce surface tension) and D: synthesis and host defence

Question 8

Hydrophobic surfactant proteins?

Answer 8

SP-B (myelin formation) and C: formation and stabiliation of the phospholipid monolayer

Question 9

Phospholipid monolayer formation?

Answer 9

lamellar body degraded into tubular myelin by SPA SPA and Ca, SPA B and C form layer

Question 10

Cells moderating phospholipid turnover?

Answer 10

type II cells, extracellular enzymes, macrophages

Question 11

Compliance definition?

Answer 11

degree to which lung will distend per unit chang in pressure (change in V/ Palv-Pip)

Question 12

Factors afecting compliance?

Answer 12

elasticity of lung tissue, surface tension of air liquid interface at alveoli

Question 13

Law of Laplace?

Answer 13

r’s are equal in sphere, therefor P=2T/r

Question 14

Fluid Balance?

Answer 14

surfactant reduces tendency for fluid to be sucked into airspace

Question 15

Host Defence?

Answer 15

surface tension gradients move matter out of alveoli towards ciliated regions, SP-A and D bind pathogen to promote phagocytosis