BIOM1060 Lecture Notes - Lecture 32: Medial Umbilical Ligament, Ligamentum Arteriosum, Ductus Venosus
BIOM1060 01/05/18
FOETAL DEVELOPMENT PHYSIOLOGY (PART 2)
Foetal brain
- Development involves massive proliferation, differentiation of neurons and glia and
organisation of brain regions
- Neural proliferation greatest between 8-15 weeks
- Reduced brain growth may cause microcephaly (caused by alcohol and radiation)
- Megalencephaly: enlargement of brain (associated with autism)
- Neurons migrate to developing cortex and deep nuclei (12-20 weeks)
o Synaptogenesis: connections between neurons (continuous throughout life)
o Synaptic pruning: removing of connections to allow others to connect
o Apoptosis: selective neuronal loss (removes unwanted cells)
Foetal circulation
- Foetus obtains nutrients/oxygen from placenta
- Umbilical cord contains 2 umbilical arteries and an umbilical vein
o Umbilical artery: carries deoxygenated blood away from foetal heart to placenta
(opposite to normal) - regresses after birth (becomes medial umbilical ligament)
o Umbilical vein: carries oxygenated blood from placenta to foetus - closes off and
forms ligamentum teres of liver after birth
- Ductus venosus: connects umbilical vein to inferior vena cava - becomes ligamentum
venosum (bypasses liver)
- Foramen ovale: opening between atria of heart - becomes fossa ovalis (connects
chambers to lungs as adults - not required as foetus)
- Ductus arteriosus: connects pulmonary trunk to aorta - becomes ligamentum arteriosum
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