Embryology

Question 1

Embryonic Stage

time period and events

Answer 1

26 days to 6 weeks
Foregut endoderm extends into surrounding mesenchyme
3 rounds of branching establish lung lobes

Question 2

Pseudo glandular Stage

time period and events

Answer 2

6-16 weeks

14 rounds of branching from form terminal bronchioles

Question 3

Canalicular Stage

time period and events

Answer 3

16-28 weeks
Terminal bronchiole divides into 2+ respiratory bronchioles
Surfactant production beings and increases as weeks progress
FETAL BREATHS CAN BE DETECTED

Question 4

Saccular Stage

time period and events

Answer 4

28-36 weeks
Respiratory bronchioles subdivide to produce terminal sacs
These continue to develop through childhood

Question 5

Alveolar Stage

time period and events

Answer 5

36 - early childhood (4-6 years)
lungs grows and alveoli mature
septae thin, single capillary network in alveolar wall, gas exchange unit established

Question 6

what determines the branching patterns?

Answer 6

mesoderm

at branch points, epithelial cell division is stopped and collagen is produced

Question 7

what aortic arch does the pulmonary vasculature come from?

Answer 7

6th aortic arch