BMS 301 Lecture Notes - Dura Mater, Thalamus, Pia Mater
Document Summary
A segment is that portion of the spinal cord that gives rise to the roots that will form a bilateral pair of spinal nerves. In fetal life, goes down to level of s2. 7th 8th month of in utero development. Cord tapers to an end conus medularis. Collection of spinal nerve roots; but not spinal cord. To see which part of cord will be affected given injury at certain bony level. Long continuous columns of white and gray matter. White matter = myelinated nerve cell processes (axons + dendrites) Central butterfly shape (cross section) gray matter. Dorsal gray made of cell bodies of connector neurons. Ventral gray alpha motor neurons (lower motor neurons, final common pathway). Only way to get information from brain to target organ. If cell body is destroyed, will not come back. Lateral gray cell bodies that belong to autonomic nervous system. Long ascending tracts (direction of nerve impulse is towards brain)
