Spinal CordSpinal Cord(Handout)(Handout)

prof. azaprof. aza

Figure 04a Spinal Cord Figure 04a Spinal Cord

The spinal cord (Figure The spinal cord (Figure 04a) lies along the 04a) lies along the middorsal line of the middorsal line of the body It has two main body It has two main functions: (1) it is the functions: (1) it is the center for many reflex center for many reflex actions, and (2) it actions, and (2) it provides a means of provides a means of commu-nication commu-nication between the brain and between the brain and the spinal nerves that the spinal nerves that leave the cord.leave the cord.

The spinal cordThe spinal cord The white matter of the cord is white The white matter of the cord is white

because it contains myelinated long fibers of because it contains myelinated long fibers of interneurons that run to-gether in bundles interneurons that run to-gether in bundles call tracts. These tracts connect the cord to call tracts. These tracts connect the cord to the brain. The dorsal ones are primarily the brain. The dorsal ones are primarily ascending to the brain, while the ventral ascending to the brain, while the ventral tracts bring information down from the brain. tracts bring information down from the brain.

The inner portion of the cord is filled with a The inner portion of the cord is filled with a mass of nerve cell bodies called gray matter. mass of nerve cell bodies called gray matter. Each spinal nerve emerges from the spinal Each spinal nerve emerges from the spinal cord as two short branches, the dorsal and cord as two short branches, the dorsal and the ventral roots. These roots join just before the ventral roots. These roots join just before the nerve leaves the vertebral column. the nerve leaves the vertebral column.

Figure 04b CNS and PNS Figure 04b CNS and PNS

These tracts connect the cord to the brain. These tracts connect the cord to the brain. The dorsal ones are primarily ascending to The dorsal ones are primarily ascending to the brain, while the ventral tracts bring the brain, while the ventral tracts bring information down from the brain. The inner information down from the brain. The inner portion of the cord is filled with a mass of portion of the cord is filled with a mass of nerve cell bodies called gray matter. Each nerve cell bodies called gray matter. Each spinal nerve emerges from the spinal cord spinal nerve emerges from the spinal cord as two short branches, the dorsal and the as two short branches, the dorsal and the ventral roots. These roots join just before ventral roots. These roots join just before the nerve leaves the vertebral column.the nerve leaves the vertebral column.

Peripheral Nervous SystemPeripheral Nervous System

Figure 05 Figure 05 Cranial Cranial Nerves Nerves

Figure 06 Figure 06 Spinal Spinal

NervesNerves