Spinal Nerves Overview

Question 1

nerve

Answer 1

• part of PNS

- hundreds of thousands of axons (each from a different neuron) wrapped in connective tissue

Question 2

ganglia

Answer 2

• collection of cell bodies of neurons (whose axons make up the nerve)

Question 3

cervical nerve pairs

Answer 3

8

Question 4

thoracic nerve pairs

Answer 4

12

Question 5

lumbar nerve pairs

Answer 5

5

Question 6

sacral nerve pairs

Answer 6

5

Question 7

coccygeal nerve pairs

Answer 7

1

Question 8

spinal nerves overview

Answer 8

• 31 pairs
• all mixed nerves
• branch out from spinal cord to innervate whole body
• each spinal nerve divides into branches (rami) almost immediately after leaving the vertebral column

Question 9

dorsal ramus

Answer 9

• smaller of the two ramii
• contains nerves serving dorsal trunk
• carries visceral + somatic motor, and sensory info to + from skin/muscles of back

Question 10

ventral ramus

Answer 10

• contains nerves serving ventral trunk, all limbs

- carries carries visceral + somatic motor, and sensory info to + from body surface, body wall structures, and limbs

Question 11

information transfer process

Answer 11

sensory information goes from:
stimuli > sensory receptors > spinal nerves > dorsal roots > spinal cord > brain

brain makes decision to move (sends motor command):
brain > spinal cord > ventral root > spinal nerve > muscle fiber > causes voluntary muscle contraction

Question 12

plexus

Answer 12

• network of interconnecting nerves
• formed when ventral ramii merge w/adjacent ventral ramii
• contains nerves w/fibers from various spinal nerves that have the same target organ