the central nervous system

Question 1

gross anatomy of spinal cord

Answer 1

1. gray matter:
   - differentiated into anterior and posterior horns
2. white matter:
   - forms ascending and descending spinal tracts
   - consists of sensory and motor fibers
3. central canal:
   - leads to 4th ventricle of brain

Question 2

spinal nerves

Answer 2

• pass through intervertebral foramen
• 31 pairs
• dorsal root=sensory nerve entry point
• dorsal root ganglion=sensory nerve cell bodies
• ventral root= motor nerve exit point

Question 3

plexus

Answer 3

-a merging network of spinal nerve trunks leading to and from a specific bodily area.

Question 4

cervical plexus

Answer 4

head, neck, upper chest, and back

Question 5

brachial plexus

Answer 5

shoulder, arm, and hand

Question 6

lumbar plexus

Answer 6

lower back, abdomen, genitalia, thigh

Question 7

sacral plexus:

Answer 7

buttocks, posterior thigh, calf, foot

Question 8

meninges

Answer 8

protective membrane covering brain and spinal cord

Question 9

Dura mater

Answer 9

-dense irregular connective tissue surrounded externally by blood vessels and fat

Question 10

arachnoid membrane

Answer 10

• squamous epithelium and elastic connective tissue.

- encloses subarachnoid space

Question 11

pia mater

Answer 11

• vascular areolar membrane supporting blood vessels

- closely adherent to the spinal cord and brain

Question 12

ascending tract—dorsal (crossover at medulla):

Answer 12

1. fasciculus gracilis; light touch and muscle position
   - sense in lower body
2. fasciculus cuneatus; light touch and muscle position
   - sense in upper body
3. spinocerebellar: subconscious muscle sense to the cerebellum—> posture control

Question 13

ascending tract—lateral (crossover at level of entry):

Answer 13

-spinothalamic; pain and temperature

Question 14

ascending tract—anterior(crossover at level of entry):

Answer 14

-spinothalamic; crude touch and pressure

Question 15

descending tracts—motor pathways from the cerebral cortex and/or the cerebellum:

Answer 15

1. pyramidal (crossover at medulla forming pyramids):
   - corticospinal; fine voluntary movement
2. extrapyramidal(crossover above medulla):
   - involuntary influence on coordination and balance