Spinal Cord (unit 3)

Question 1

Adult spinal cord dimensions

Answer 1

-About 45cm (18 inch) long
-Shorter than the vertebral column
•Ends between L1 and L2

Question 2

Spinal cord divided into 31 segments

Answer 2

• 8 cervical
• 12 thoracic
• 5 lumbar
• 5 sacral
• 1 coccygeal

Question 3

Conus medullaris

Answer 3

-Tapered, cone-shaped part of the spinal cord inferior to the lumbar enlargement

Question 4

Cauda equina

Answer 4

• Collection of dorsal and ventral roots of spinal segments L2 to S5 along with filmy terminale
• Name comes from resemblance to a horse’s tail

Question 5

Film terminale

Answer 5

• Slender, strand of fibrous tissue extending from inferior tip of conus medullaris to second sacral vertebra
• Provides longitudinal support to Spinal Cord

Question 6

Spinal meninges

Answer 6

-Series of Specialized membranes surrounding the spinal cord
•Provide physical stability and shock absorption
•Blood vessels within layers deliver oxygen and nutrients to spinal cord

Question 7

Three layers of cranial meninges

Answer 7

• Dura mater: tough, fibrous outer layer
• Arachnoid mater: middle layer
• Pia mater: innermost layer

Question 8

Subarachnoid space

Answer 8

-Attach Arachnoid Mater to Pia mater

-Filled with cerebrospinal fluid (CSF)
•Acts as shock absorber and diffusion medium for gases, nutrients, chemical messengers, and wastes

Question 9

Epidural space

Answer 9

• Between Dura Mater and walls of vertebral canal

- Contains Areolar Tissue, blood vessels, and Adipose tissue

Question 10

Superficial layer of WHITE MATTER

Answer 10

• Contains Large Numbers of myelinated and unmyelinated axons
• Contains ascending/descending nerve tracts

Question 11

Deep layer of GRAY MATTER

Answer 11

• Dominated by cell bodies of neurons and neuroglia organized into functional nuclei
• Surrounds small central canal
• Forms an H or butterfly shape

Question 12

Sensory nuclei

Answer 12

-Receive and relay sensory information

Question 13

Motor nuclei

Answer 13

Issue motor commands to peripheral

Question 14

Posterior gray horns

Answer 14

-Somatic sensory and visceral nuclei

Question 15

Lateral gray horns

Answer 15

Visceral motor nuclei

Question 16

Anterior gray horns

Answer 16

Somatic motor nuclei

Question 17

Gray commissure

Answer 17

• consists of axons crossing from one side to the other

Question 18

Spinal nerves

Answer 18

• 31 pairs of spinal nerves
• Cervical region (C1-C8)
• Thoracic (T1-T12)
• Lumbar (L1-L5)
• Sacral/Coccygeal (6 total)

Question 19

Spinal nerves

Answer 19

-Contain axons of sensory and motor neurons

Question 20

Ventral root

Answer 20

-Contains axons of motor neurons

Question 21

Dorsal root

Answer 21

• Contains axons of sensory neurons whose cell bodies are in the dorsal root ganglion

Question 22

Dorsal root ganglion

Answer 22

• Contains cell bodies of sensory neurons

- Each Spinal Cord segment has pair of dorsal root ganglia (one on each side)

Question 23

Branches are called?

Answer 23

• Rami

- Ramus (singular)

Question 24

Dorsal Ramus

Answer 24

-Innervates muscles, joints, and skin of the back

Question 25

Ventral Ramus

Answer 25

-Innervates structures in the upper and lower limbs and the lateral and anterior trunk

Question 26

Communicating Rami

Answer 26

• Present in the thoracic and superior lumbar segments of spinal cord
• Contain axons of sympathetic neurons