CHAPTER 13: The Spinal Cord, Spinal nerves, and Somatic Reflexes

Question 1

What are the 4 principal functions of the spinal cord? CNLR

Answer 1

Conduction
Neural integration
Locomotion
Reflexes

Question 2

Simple repetitive muscle contractions that put one foot in front of another over and over are coordinated by groups of neurons called ___________.

Answer 2

Central Pattern Generators

Question 3

The spinal cord is divided into what 4 regions? CTLS

Answer 3

Cervical
Thoracic
Lumbar
Sacral

Question 4

What are the 2 areas in which the cord is a little thicker than usual?

Answer 4

Cervical enlargement
Lumbosacral enlargement

Question 5

Inferior to the lumbosacral enlargement, the cord tapers to a point called the ____________.

Answer 5

Medullary cone

Question 6

A bundle of nerve roots from L2 to S5 under medullary cone that resemble’s a horse’s tail, innervates pelvic organs and lower limbs.

Answer 6

Cauda equina

Question 7

The spinal cord and brain are enclosed in 3 fibrous membranes called what ____________.

Answer 7

Meninges

Question 8

From superficial to deep what are the 3 meninges of the brain/spinal cord? DAP

Answer 8

Dura mater
Arachnoid mater
Pia mater

Question 9

The dura mater forms a loose-fitting sleeve called the ________.

Answer 9

Dural sheath

Question 10

What is the space between vertebral bone and the dural sheath?

Answer 10

Epidural space

Question 11

This layer of the meninges consists of a membrane that is 5-6 layers of squamous to cuboidal cells adhering to inside of dura mater.

Answer 11

Arachnoid membrane

Question 12

Between the arachnoid membrane and the Pia mater is a space that is filled with cerebrospinal fluid. What is that space called?

Answer 12

Subarachnoid space

Question 13

When a sample of cerebrospinal fluid is needed it is taken from the lumbar cistern by a procedure called what ?

Answer 13

Spinal tap or lumbar puncture

Question 14

This is a delicate transparent membrane that is composed of one to two layers of squamous to cuboidal cells and delicate collagenous and elastic fibers.

Answer 14

Pia mater

Question 15

This transparent membrane continues beyond the medullary cone as a fibrous strand called the terminal filum and also fuses with the dura mater to form coccygeal ligament.

Answer 15

Pia mater

Question 16

The spinal cord contains two different types of nervous tissue. What are they?

Answer 16

Gray matter
White matter

Question 17

This nervous tissue of spinal cord contains little myelin, cell bodies, dendrites, proximal parts of axons of neurons, and is site of synaptic contact between neurons.

Answer 17

Gray matter

Question 18

This nervous tissue of spinal cord has bright pearly white appearance, abundance of myelin, composed of axon bundles that course up and down spinal cord.

Answer 18

White matter

Question 19

The spinal cord has a central core of gray matter that looks _________ shaped. Contains 2 _________ dorsal horns and 2 __________ ventral horns. In the middle is the _______ canal.

Answer 19

butterfly; posterior; anterior; central

Question 20

In gray matter, the gray commissure contains the ___________ which is collapsed in most areas of adult spinal cord but in some places (and in young children) it remains open lined with ependymal cells and filled with CSF.

Answer 20

Central canal

Question 21

Knowledge of locations and functions of spinal tracts is essential for what?

Answer 21

Diagnosing / managing spinal cord injuries

Question 22

These tracts carry sensory information up the spinal cord.

Answer 22

Ascending tracts

Question 23

These tracts conduct motor signals down the spinal cord.

Answer 23

Descending tracts

Question 24

Many of the spinal tracts undergo a process where they cross over from the left side of the body to the right or vice versa. Left side of brain ends up receiving sensory information from the right and send motor commands to that side.

Answer 24

Decussation

Question 25

When the origin and destination of a tract are on opposite sides we say they are __________ to each other.

Answer 25

Contralateral

Question 26

When a tract doesn't decussate, its origin and destination are on the same side of body, we say they are _________.

Answer 26

Ipsilateral

Question 27

When obtaining CSF during spinal tap procedure, the skin over lumbar vertebrae is anesthetized and needle is inserted between spinous processes of _____ and ______. Why?

Answer 27

L3 AND L4; spinal cord doesn't extend this far and isn't exposed to injury by a needle

Question 28

These nerves are composed of afferent fibers and they include nerves for smell and vision. Carry signals from receptors to CNS.

Answer 28

sENSORY NERVES

Question 29

These nerves carry only efferent fibers, carry signals from CNS to muscles/glands.

Answer 29

Motor nerves

Question 30

These nerves have both afferent and efferent fibers and conduct signals in both directions.

Answer 30

Mixed signals

Question 31

This is the knot-like apperance of a nerve. It is a cluster of nerve cell bodies outside the CNS. Enveloped in an epineurium continuous with nerve.

Answer 31

Ganglion

Question 32

How many pairs of spinal nerves are there ?

Answer 32

31 pairs

Question 33

The first 8 spinal nerves are __________

Answer 33

cervical nerves C1-C8

Question 34

The 12 spinal nerves under cervical nerves are _________

Answer 34

thoracic nerves T1-T12

Question 35

The spinal nerves under thoracic are ____________ and they are 5 pairs.

Answer 35

Lumbar nerves L1-L5

Question 36

Under lumbar nerves are 5 _________ nerves

Answer 36

sacral nerves S1-S5

Question 37

The 1 nerve under sacral nerves is the __________

Answer 37

coccygeal nerve

Question 38

What are the 5 different nerve plexuses? CBLSC

Answer 38

Cervical plexus Brachial plexus Lumbar plexus Sacral plexus Coccygeal plexus

Question 39

This plexus is located on each side of neck, has major nerves that travel down each side of mediastinum, innervate diaphragm, and play a role in breathing.

Answer 39

cervical plexus major nerve: phrenic nerve

Question 40

This plexus passes over the first rib into the axilla and innervates the upper limb and some muscles of neck and shoulder.

Answer 40

Brachial plexus

Question 41

What are the major nerves of the brachial plexus? RMU

Answer 41

Radial nerve Median nerve Ulnar nerve

Question 42

This plexus