lecture 20 - spinal cord & nerves

Question 1

Where does the spinal cord originate?

Answer 1

The foramen magnum, the opening at the base of the skull.

Question 2

Where does the spinal cord end?

Answer 2

At the inferior border of the 1st lumbar vertebra (L1)

Question 3

What is the spinal cord contained within?

Answer 3

Sits within meningeal sac within the spinal cavity of the vertebrae.

Question 4

Where does the meningeal sac extend down to?

Answer 4

The coccyx.

Question 5

What is the ‘hole’ within a vertebra called?

Answer 5

The vertebral foramen

Question 6

What is the orientation of a vertebra?

Answer 6

Vertebral body sits posterior, while the spinous process sits anteriorly.

Question 7

What is the meningeal sac filled with?

Answer 7

Cerebrospinal fluid

Question 8

What is the end of the spinal cord called?

Answer 8

Conus modularis

Question 9

What anchors the spinal cord, and how?

Answer 9

The filium terminale - provides fibrous, non-neural anchor that extends to the base of the spinal cavity.

Question 10

What are the filium terminale?

Answer 10

Fibrous, non-neural tissues that anchors the spinal cord to the base of the spinal cavity.

Question 11

How many segments does the spinal cord have?

Answer 11

31

Question 12

How many spinal nerves are associated with each segment of the spinal cord?

Answer 12

2

Question 13

How are spinal nerves named?

Answer 13

By the vertebra they exit below (except for the cervical vertebra, that are ‘one off’)

Question 14

How are the nerves of the cervical vertebrae named?

Answer 14

Based on the vertebrae they exit below, plus 1. The first exits between the skull and first cervical vertebra (above it).

Question 15

Where do spinal nerves exit the spinal cord/vertebral column?

Answer 15

At the vertebral level appropriate to their origin. e.g. nerves originating in lumbar spinal cord exit between lumbar vertebrae.

Question 16

What is the name for the large collection of long nerves at the inferior end of the spinal cord?

Answer 16

Cauda equina

Question 17

In the spinal cord, where are bundles of axons found?

Answer 17

The dorsal, ventral and lateral columns

Question 18

In the spinal cord, where are bundles of cell bodies found?

Answer 18

In the dorsal, lateral and ventral horns

Question 19

What are the bundles of axons leaving the spinal cord?

Answer 19

Dorsal and ventral nerve roots.

Question 20

Is the dorsal side of the spinal cord posterior or anterior?

Answer 20

Posterior

Question 21

Is the ventral side of the spinal cord posterior or anterior?

Answer 21

Anterior

Question 22

Where do dorsal and ventral nerve roots leave the spinal cord?

Answer 22

Via intervertebral foramen - holes formed between adjacent vertebrae

Question 23

Where does afferent/sensory information arrive at the spinal cord?

Answer 23

At the dorsal nerve root (containing axons), via the dorsal root ganglion (containing cell bodies)

Question 24

Where does efferent/motor info leave the spinal cord?

Answer 24

Through ventral nerve roots (containing axons)

Question 25

Where are somatic efferent motor neurons found in the spinal cord?

Answer 25

Ventral horn

Question 26

Where are autonomic (sympathetic) neurons found in the spinal cord?

Answer 26

Lateral horn

Question 27

Where are the cell bodies of sensory neurons entering the spinal cord found?

Answer 27

Dorsal root ganglia.

Question 28

What are the three branches of a spinal nerve?

Answer 28

dorsal ramus, ventral ramus, rami communicans

Question 29

What is the information flowing through the dorsal ramus?

Answer 29

Efferent and afferent info to and from the back.

Question 30

What is the information flowing through the ventral ramus?

Answer 30

Efferent and afferent info too/from the ventral/front side of the body.

Question 31

What is the information flowing through the rami communicans?

Answer 31

Sympathetic info

Question 32

What segments of the spinal cord are Rami communicans found in?

Answer 32

T1-L2

Question 33

What is the structure of the Rami communicans?

Answer 33

Two branches from the spinal nerve come together to form the sympathetic chain ganglion

Question 34

What connective tissue covers axons?

Answer 34

Endoneurium

Question 35

What is a bundle of axons called?

Answer 35

A fascicle.

Question 36

What is the connective tissue that covers peripheral nerve fascicles?

Answer 36

Perineurium

Question 37

What is the structure of a nerve?

Answer 37

Bundles of fascicles and blood vessels covered by epineurium (connective tissue)

Question 38

What is the connective tissue that covers nerves?

Answer 38

Epineurium