Respiratory

Question 1

embryonic
lung development
time period
Critical events

Answer 1

22 days -6/8 weeks

respiratory diverticulum and proximal airways develop

Question 2

T/F the lungs continue to develop post-natal

Answer 2

TRUE

Question 3

pseudoglandular stage in lung development

Answer 3

second stage

Question 4

pseudoglandular stage
lung development
time period
Critical events

Answer 4

6 weeks to 16 weeks

brnaching ro form terminal bronchioles (pre-acinar)

HISTOLOGICAL STRUCTURE OF THE LUNG RESEMBLES A GLAND

Question 5

can the fetus servive with lung development at the pseudoglandular stage of development

Answer 5

NO - histologically there is structure that represents a gland but ONLY UP TO THE TERMINAL BRONCHIOLES - so there is no alveolar cells

born during this period of development fetuses are unable to survive

Question 6

canalicular stage of lung development
time period
critical events
survival?

Answer 6

third stage
16 weeks to 16 weeks

respiratory bronchioles form with PRIMITIVE CAPILLARY NETWORK - ACINAR

INTENSE GROWTH OF BLOOD VESSELS

born LATE in this stage - fetus able to survive - but if born in the beginning there is not enough surfactant produced yet for survival

Question 7

Terminal / saccular stage of devlopment
time line
critical events

Answer 7

weeks 26- bith

results in MATURE CAPILLARY - ENDOTHELIAL INTERFACE/ BLOOD-AIR BARRIER.

see secondary crest formations occuring which is increasing the SA for gas exhange - these are ridges of the epithelial lined mesenchyme that subdivide into saccules

increase in elastic network

with increasing levels of surfactant we see increasing / greater chance of survival if delivery of fetus pre maturely occurs during this stage

Question 8

growth and maturation of the lungs continues until when

Answer 8

up to 8-10 years of life with continued branching

Question 9

Alveolar stage of lung development
time line
critical events

Answer 9

5th stage of lung development
from 32 weeks - to birth and POST-NATAL.

see an increase in respiratory bronchioles and alveoli
alveoli will form adult shape and growth after birth is attributed to increase in number of respiratory bronchioles and alveoli

interstitial mesenchyme will continue to thin

Question 10

when do we first see surfactant

Answer 10

around week 20 in the canalicular stage

Question 11

when do we have a MEASURABLE amount of surfactant?

Answer 11

WEEKS 24-28 - LATE in the canicular stage is when you can first have a pre mature fetus born with chance of survival
- measurable = when we see survival

but not in the early canalicular

Question 12

when does surfactant accelerate in production

Answer 12

35 weeks it accelerates