Spinal Cord

Spinal Cord
Within bony vertebral column.
Cylindrical of soft tissue (little finger).
Cross-section ? central butterfly (gray matter):
Interneuron
Cell bodies
Dendrites of efferent neurons
Entering fibers of afferent neurons
Glial cells.

Gray matter (Lacks myelin).
White matter
Myelinated axons of interneuron “fiber tracts or pathways”.
Descending: Relay information from brain to spinal cord.
Ascending: Transmit information to brain.
Others: Transmit information between different levels of brain and spinal cord.

Afferent fibers enter spinal cord via dorsal root.
Cell bodies of the afferent neurons “dorsal root ganglia.
Efferent neurons leaves spinal cord via ventral roots.

Reflex

An involuntary motor response to an adequate sensory stimulus that occurs subconsciously, without the mediation of the cerebral cortex
i.e., withdrawal reflex
Dorsal and ventral roots from same level combine ? spinal nerve, one on each side of spinal cord.

Motor Functions of the Spinal Cord
(Cord Reflexes)