These nerves are divided into 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal nerve Figure 3.
Each ascending dorsal root axon, before reaching the spinal cord, bifurcates into ascending and descending branches entering several segments below and above their own segment.
It is composed of neuronal cell bodies; neuropil; glial cells and capillaries but few myelinated nerve fibers.
Each spinal cord segment innervates a dermatome see below and Figure 3.
These two work together to ensure that the body functions normally.
Physiology of Reflexes Reflex movements are movements initiated by sensory receptors, which, by having synaptic contacts within the spinal cord, are a basic level of regulation of muscles or glands.