Mod5-Obj2: Gray matter

Question 1

Gray matter is composed of…

Answer 1

Cell bodies&dendrites of neurone unmyelinated axons and neuroglia

• Varies in size and shape down the spinal cord
• Surrounds the central canal

Question 2

Gray matter is organised into gray horns:

Answer 2

1. ) Posterior (dorsal) gray horns
2. ) Lateral gray horns (thoracic&lumbar regions only)
3. ) Anterior (ventral) gray horns

Question 3

Gray commissures

Answer 3

Axons cross over (decussate) from one side of the cord to the other
(connect two halves of the CNS)

Question 4

The cell bodies of neurons within the gray matter are organised into functional groups called…

Answer 4

nuclei

-Sensory nuclei and motor nuclei

Question 5

Sensory nuclei

Answer 5

Contain the cell bodies of spinal cord interneurons

-Receive and integrate sensory information entering the spinal cord

Question 6

Example of sensory nuclei entering the spinal cord

Answer 6

Sensory neuron (visceral), sensory neuron (somatic), dorsal root ganglion, dorsal root

Question 7

Motor nuclei

Answer 7

Contain the cell bodies of motor neurons

• Receive motor output issues by the brain
• Relay motor output to peripheral effectors
• Generate motor output that mediates spinal reflexes

Question 8

Example of motor nuclei entering the spinal cord

Answer 8

Axons of preganglionic neurons meet axons of lower motor neurons and enter the spinal cord via the ventral root

Question 9

Motor nuclei of lateral gray horns

Answer 9

cell bodies of preganglionic neurons (ANS)

-only in the thoracic and lumbar regions

Question 10

Motor nuclei of anterior gray horns

Answer 10

Cell bodies of lower motor neurons (somatic NS)

-Throughout the spinal cord