Random embryology facts

Question 1

What do neural crest cells give rise to?

Answer 1

• Cranial: Parts of pharyngeal pouches and arches. Cranial sensory ganglia
• Trunk:
  
  • melanocytes
  • dorsal root, sympathetic chain, parasympathetic gangila
  • chromaffin cells of adrenal medulla
  • ENS
• Cardiac: spiral septum between Aorta and PA

Question 2

Median nasal prominences fuse to give rise to what?

Maxillary prominences?

If they don’t fuse?

Answer 2

Median nasal prominences fuse to form the intermaxillary segment, which gives rise to the philtrum of upper lip, four medial maxillary teeth, primary palate.

Maxillary prominences fuse to form the palatine shelves which form the secondary palate.

Failure of the palatine shelves to fuse results in cleft palate.

Failure of the median nasal prominences to fuse with the maxillary prominences results in cleft lip.

Question 3

Which two vitamins does breast milk lack?

Answer 3

D and K. K is supplemented by injection at birth, D can usually be helped with sunlight.

Question 4

Differential cyanosis (feet are blue, arms are not). Which two conditions?

Answer 4

Coarctation in neonates.

In older children, it’s PDA with Eisenmenger’s. - can’t survive for that long with a severe coarct.

Question 5

Where does fetal erythropoiesis take place (as a function of time)?

Answer 5

1. 0-10 weeks: Yolk sac
2. 10-30+ weeks: Liver (mostly) and spleen
3. 30+ weeks: bone marrow takes over

Question 6

What are the derivatives of:

Truncus Arteriosus, bulbus cordis, primitive ventricle, primitive atria, left horn of sinus venosus, right horn of sinus venosus, cardinal veins?

Answer 6

• Truncus: aortic arches, PA, Aorta
• Bulbus cordis: left & right ventricular outflow tracts (smooth parts)
• Primitive ventricles: trabeculated parts of ventricles
• Primitive atria: trabeculated parts of atria
• Left horn of sinus venosus: coronary sinus
• Right horn of sinus venosus: smooth part of right atrium
• cardinal veins
  
  • right and common: SVC and brachiocephalic veins
  • left brachiocephalic

Question 7

Fetal alcohol syndrome

Answer 7

• Holoprosencephaly
• facial abnormalities
• heart defects