Introduction

Anatomy

Introduction

·         Hilton's law: The nerve supplying a joint also supplies the muscles that move the joint and the skin covering the insertion of such muscles.

1. Unipolar (pseudounipolar) neurons - Have one process, which divides into a central branch that functions as an axon and a peripheral branch that serves as a dendrite.Are called pseudounipolar because they were originally bipolar. The two processes fuse during development to form a single process that bifurcates at a distance from the cell body.Are sensory neurons of the PNS and found in spinal and cranial nerve ganglia.

2. Bipolar neurons - Have two processes (one dendrite and one axon); are sensory; and are found in the olfactory epithelium, the retina, and the inner ear.

3. Multipolar neurons - Have several dendrites and one axon and are most common in the CNS e.g., motor cells in anterior and lateral horns of the spinal cord, autonomic ganglion cells.

·         Lymphatic Vessels are absent in the brain, spinal cord, eyeballs, bone marrow, splenic pulp, hyaline cartilage, nails, and hair.

·         Dorsal root ganglia consist of cell bodies of the unipolar or pseudounipolar neurons and have no synapses.

·         The lateral horns are found in the gray matter of the spinal cord between T1 and L2 and also between S2 and S4.