Chapter 13 – Anatomy of the Nervous System
The Embryologic perspective:
Sixteen days after fertilization (zygote), embryo’s cells develop into three germ layers:
Endoderm, or inner tissue, is responsible for generating the lining tissues of various spaces within the body such as the mucosae of the
digestive and respiratory systems.
Mesoderm, or middle tissue, gives rise to most of the muscle and connective tissues.
Ectoderm, or outer tissue, develops into the integumentary system (the skin) and the nervous system.
During embryonic development, thin, flat layer of ectoderm begins to thicken to form the neural plate, which then invaginates to form the neural groove, which
is also sometimes referred to as the neural fold. As the neural folds come together and converge, the underlying structure forms into a tube just beneath the
ectoderm called the neural tube. Cells from the neural folds then separate from the ectoderm to form a cluster of cells referred to as the neural crest.
The anterior end of the neural tube will develop into the brain (forebrain, the midbrain, and the hind brain)
the posterior end of the neural tube will become the spinal cord.
The neural crest develops into peripheral structures.
