PSY 100 Lecture Notes - Lecture 7: Neural Development, Organogenesis, Prenatal Development
1 Dec 2020
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Document Summary
The human brain is assembled during the first two trimesters of prenatal development. By the time babies are born, they have ~ 100 billion neurons, or nerve cells. Neurons: nerve cells that handle information processing at the cellular level in the brain. Neural tube: initial formation of the nervous system starting as a pear-shaped, long, hollow tube located along the embryo"s back. The neural tube begins to form around 18-24 days after conception and develops out of the ectoderm. The tube closes at the top and bottom at about 24 days after conception. Two birth defects associated with failure of the neural tube to close are anencephaly and spina bifida; Anencephaly: highest regions of the brain fail to develop when the fetus has anencephaly or when the head end of the neural tube fails to close; these infants die in the womb. Spina bifida: results in varying degrees of paralysis of the lower limbs.
