PSY610 Final Term Notes

PSYP 610 Final term short notes

This lesson introduces the step-by-step process of how the nervous system develops — starting from the earliest stages of life in the womb.

1. Overview

The nervous system starts to form in the third week of embryonic development. The process involves highly organized stages that transform a simple group of cells into a complex network of neurons and brain structures.

Q2. Key Stages of Development

1. Neural Induction

A portion of the embryo’s ectoderm (outer layer) is instructed to become neural tissue. This occurs due to signals from a structure called the notochord. The induced tissue forms the neural plate, which folds to become the neural tube.

b. Formation of the Neural Tube The neural tube gives rise to the brain and spinal cord. Closure of the neural tube is critical; failure can result in defects like: Spina bifida Anencephaly

c. Primary Brain Vesicles The neural tube expands to form three major sections:

1. Prosencephalon (forebrain)
2. Mesencephalon (midbrain)
3. Rhombencephalon (hindbrain)

These further divide into secondary vesicles that will develop into specific brain regions (like the cortex, cerebellum, etc.).

d. Cell Proliferation (Neurogenesis) Involves the rapid division of cells to create neurons and glial cells. Most neurons are generated prenatally in specialized areas called ventricular zones.

e. Neuronal Migration