Lab 12 — Part 2

Lateral horn of the spinal cord

A region of gray matter containing the cell bodies of visceral motor neurons.

Posterior (dorsal) horn of the spinal cord

The posterior region of gray matter that receives sensory information entering the spinal cord.

Dorsal root

The root through which sensory information enters the spinal cord.

Dorsal root ganglion

A swelling containing the cell bodies of somatic sensory neurons.

Ganglion cell bodies

Neuron cell bodies located in a ganglion; in the dorsal root ganglion, they are somatic sensory neuron cell bodies.

Satellite cells

Supporting cells associated with the neuron cell bodies in a ganglion.

Nerve fibers

Neuronal processes that carry information to or from the nervous system.

Ventral root

The root through which motor information leaves the spinal cord.

Spinal nerve

A nerve associated with the spinal cord that contains both sensory and motor information.

Meninges

The connective tissue coverings surrounding the spinal cord and brain.

Three layers of the meninges

Dura mater, arachnoid mater, and pia mater.

Dura mater

The outermost layer of the meninges.

Arachnoid mater

The middle layer of the meninges.

Pia mater

The innermost meningeal layer that closely covers the nervous tissue.

Absence of the lateral horn

The lateral horn is not present at every level of the spinal cord.

Information traveling through the ventral root

Somatic motor information traveling from the spinal cord to the periphery.

Pathway of somatic motor information

Somatic motor neuron cell body in anterior horn → ventral root → spinal nerve → periphery.

Information traveling through the dorsal root

Somatic sensory information traveling from the periphery into the spinal cord.

Pathway of somatic sensory information

Periphery → spinal nerve → dorsal root → dorsal root ganglion → spinal cord.

Location of somatic sensory neuron cell bodies

In the dorsal root ganglion.

Location of somatic motor neuron cell bodies

In the anterior (ventral) horn of the spinal cord gray matter.

Location of visceral motor neuron cell bodies

In the lateral horn, when the lateral horn is present.

Visceral motor system

Also known as the autonomic nervous system.

Gray matter vs. white matter

Gray matter contains neuron cell bodies, while white matter contains nerve fibers.

Difference between dorsal and ventral roots

Dorsal root carries sensory information in; ventral root carries motor information away.

Difference between dorsal root ganglion and spinal nerve

Dorsal root ganglion contains sensory cell bodies; spinal nerve contains sensory and motor nerve fibers.

Structures in dorsal root ganglion preparation

Ganglion cell bodies, satellite cells, and nerve fibers.

Spinal cord gray matter horns and functions

Anterior horn: somatic motor; lateral horn: visceral motor; posterior horn: receives sensory info.

Structures to identify on cord and ganglion preparations

Spinal cord, fissures, sulci, central canal, white/gray matter, roots, ganglion, nerve, and meninges.

Major functional pathways to trace

Somatic motor and somatic sensory pathways connecting spinal cord and periphery.