Respiratory - Embryology and Anatomy

Question 1

when does lung development occur and what includes initial development?

Answer 1

1. during week 4

2. initial development includes development of lung bud from distal end of respiratory diverticulum.

Question 2

What is lung bud?

Answer 2

AKA respiratory diverticulum.

it is the outgrowth of foregut (future esophagus) and is formed during week 4.

Question 3

what are stages of lung development ?

Answer 3

1. embryonic (4w - 7w)
2. Pseudoglandular (5 w - 17w)
3. canalicular (16w-25 w)
4. saccular (26 w-birth)
5. alveolar (36 w-8 year)

every pulmonologist can see alveoli

Question 4

review structural development of lung according to stages

Answer 4

1. lung bud-trachea-bronchial bud-mainstem bronchi-secondary (lobar) bronchi- teritary (segmental) bronchi
2. endodermal tubules-terminal bronchioles (modest capillary network)
3. terminal bronchioles - respiratory bronchioles - alveolar ducts (prominent capillary network).
4. alveolar ducts- terminal sacs (seperated by 1 septae)
5. terminal sacs - adult alveoli (due to 2 septation)

Question 5

when is developmental lung surrounded with modest capillary network?

Answer 5

5-17 w (pseudoglandular)

Question 6

when is developmental lung surrounded by prominent capillary network ?

Answer 6

16 - 25 w (canalicular)

Question 7

From when is respiration capable?

Answer 7

at 25 week

Question 8

at which stage errors can lead to tracheoesophageal fistula?

Answer 8

at embryonic stage (4-7w)

Question 9

when do pneumcytes start developing ?

Answer 9

at 20 weeks