Chapter 12 (Spinal Cord, Spinal Nerves, and Spinal Reflexes)

Where is the cerebrospinal fluid that surrounds the spinal cord located?

Cerebrospinal fluid is found in the subarachnoid space, which lies beneath the epithelium of the arachnoid mater and superficial to the pia mater.

A disease that damages myelin sheaths would affect which portion of the spinal cord?

A disease that damages myelin sheaths would affect the white matter columns of the spinal cord, which are composted of bundles of myelinated axons.

A typical spinal cord has how many pairs of spinal nerves, and where does the spinal cord end?

A typical spinal cord has 31 pairs of nerves, and the spinal cord ends at the level of lumbar vertebra 1 or 2 (L1 or L2).

Differentiate between sensory nuclei and motor nuclei.

Sensory nuclei receive and relay snesory information from peripheral receptors; motor nuclei issue motor commands to peripheral effectors.

Describe the composition of the gray matter of the spinal cord.

The Gray matter in the spinal cord is composed of the cell bodies of neurons, neuroglia, and unmyelinated axons.

Name the structures and spinal coverings that would be penetrated during a lumbar puncture procedure.

The lumbar puncture needle would penetrate the epidermis, dermis, subcutaneous layer (hypodermis), and then skeletal muscle before reaching the protective spinal coverings: the dura mater, then the arachnoid matter, and finally the subarachnoid space, which contains cerebrospinal fluid.

A person with polio has lost the use of his leg muscles. In which area of his spinal cord would you expect the virus-infected motor neurons be?

The poliovirus-infected neurons would be in the anterior gray horns of the spinal cord, where the cell bodies of somatic motor neurons are located.

Identify and describe the three spinal meninges.

The three spinal meninges are the dura mater, arachnoid mater, and pia mater

Describe the gross anatomical features of a cross section of spinal cord.

anterior median fissure, the posterior median sulcus, white matter, gray matter, the central canal, a dorsal root of each spinal nerve, a ventral root of each spinal nerve, dorsal root ganglia, and spinal nerves