Nervous System 4

Question 1

Spinal Cord

Answer 1

The vertebral column (bone) forms a cavity called the vertebral canal.
The well-protected spinal cord (nervous tissue) lies inside.

Question 2

Spinal Cord functions

Answer 2

The functions of the spinal cord include:
• provides two-way communication to and from the brain and the body
• major reflex centre

Question 3

Protective coverings of the spinal cord

Answer 3

The spinal dura mater is not attached to the vertebrae.
• the space between called epidural space contains cushion of fat and network of veins
The dural and arachnoid mater extend beyond the spinal cord.
• lumbar puncture or tap is performed within the subarachnoid space to remove a sample of cerebrospinal fluid

Question 4

The spinal cord begins at the foramen magnum

Answer 4

and ends at the lumbar reguon(L1-L2) called conus medullaris
- it creates paired spinal nerves along its length

Question 5

Spinal nerves that exit the spinal cord form a structure called

Answer 5

The cauda equina

Question 6

Internal Anatomy of the S.c.

Answer 6

Gray matter forms the internal H/butterfly shape.
It is divided into:
• dorsal (posterior) horns: contain interneurons that receive sensory fibres.
• ventral (anterior) horns: contain both motor neurons and interneurons.
• lateral horns (only in thoracic and superior lumbar regions): contain sympathetic neurons.

Question 7

Axons that enter and exit the spinal cord form the following in the PNS

Answer 7

ventral roots: bundle of motor neuron axons that exit the spinal cord.
• dorsal roots: sensory neuron axons that enter the spinal cord.
• dorsal root (spinal) ganglia: cell bodies of sensory neurons.
• spinal nerves: formed by fusion of dorsal

Question 8

White matter

Answer 8

Forms the outer layer which has nerve tracts that allows comm between parts of the CNS

Question 9

Nerve tracts in the spinal cord run in 3 dirs

Answer 9

Ascending, descending and transverse

Question 10

Nerve tracts in the spinal cord run in 3 dirs

Answer 10

Ascending, descending and transverse

Question 11

Spinal tracts have 3 properties

Answer 11

decussation: most pathways cross cover from one side of CNS to other (contralateral pathways).
• relay: pathways contains two or more neurons in series to transmit nerve impulses.
• symmetry: pathways are paired symmetrically (left and right) within the spinal cord.