Physiological and pathological formation of spinal cord Flashcards
What does ectoderm form
skin + nervous system
What does endoderm form?
Epithelial lining of gut and respiratory system/liver/pancreas
What does the mesoderm form
Notochord and muscular system
What will thicken in 4th week
The ectoderm thickens to form the neural plate
Neural crest cells
In the upper ectoderm give rise to melanocytes.
What does melanocytes produce
Melanin
What else does
- ) sCHWANN cells
- ) Adrenal medulla
- ) Bony skull
- ) Meninges
- ) Sensory dorsal root ganglia of spinal cord and cranial nerves
Abnormalities of the spinal cord
- failure to close cephalic region: anencephaly
- failure to close spinal region: spina bifida
- collectively called neural tube defect
When does the neural tube close
- neural tube usually closes at end of 4th embryonic week
Spina bifida risk and environmental factors
- 1 sibling: 2%
- 2 siblings: 10%
- parents: 4%
- environmental factors: folic acid/maternal diabetes
Syndromic causes of neural tube defects
1.) Meckel Syndrome: NTD/ Cystic kidney malformation/ extra fingers
What structures are present at four weeks (brain)?
Prosencephalon:
Mesencephalon
Rhombencephalon
Spinal cord
What structures are present at six weeks (brain)?
Telencephalon:
Mesencephalon:
Fourth ventricle:
Rhombencephalon:
What is microcephaly
Head is too small
What is macrocephaly
Head is too big
