Embryology

Question 1

Where is the respiratory tract derived from?

Answer 1

Foregut

Question 2

Are the lungs working in a foetus?

Answer 2

No

Question 3

Describe the steps of first breath when a baby is born.

Answer 3

1. Fluid in lungs is squeezed out by birth process
2. Adrenaline is released due to stress which increases surfactant release
3. Air is inhaled
4. Oxygen vasodilates pulmonary arteries
5. Umbilical arteries and ductus arteriosus constrict becoming the medial umbilical ligaments + ligamentum arteriousum

Question 4

When does surfactant production from type II pneumocytes start?

Answer 4

34 weeks gestation. There is a dramatic increase 2 weeks prior to birth.