A&p I: Spinal Cord

Front 1

Number of spinal nerves

Back 1

31 pairs

Front 2

The spinal cord is a little thicker at the _____________________ and gives rise to nerves of the upper limbs

Back 2

Cervical enlargement

Front 3

The spinal cord is a little thicker at the______________________ and gives rise to nerves of the lower limbs

Back 3

lumbar enlargement

Front 4

What is the medullary cone?

Back 4

Place inferior to the lumbar enlargement where the spinal cord tapers to a point

Front 5

The ______________________ is a bundle of nerve roots arising from the lumbar enlargement and medullary cone that innervates the pelvic organs and lower limbs

Back 5

cauda equina

Front 6

Define meninges

Back 6

fibrous connective tissue membranes covering the central nervous system

Front 7

Define epidural space

Back 7

the space between the vertebral bones and the dural sheath

Front 8

Describe the dura mater

Back 8

It is a tough, collagenous membrane about as thick as a rubber kitchen glove

Front 9

Describe the arachnoid mater

Back 9

consists of simple squamous epithelium that adheres to the inside of the dura, and a loose mesh of collagenous and elastic fibers spanning the gap between the arachnoid mater and the pia mater

Front 10

What fills the subarachnoid space?

Back 10

CSF

Front 11

Describe the pia mater

Back 11

delicate, transparent membrane that closely follows the contours of the spinal cord

Front 12

What two structures fuse to form the coccygeal ligament, and what does it do?

Back 12

Dura mater and pia mater fuse at the level of vertebra S2

It anchors the cord and meninges to vertebra Co1

Front 13

What are denticulate ligaments?

Back 13

regularly occurring extensions of the pia that extend through the arachnoid to the dura and anchor the cord, limiting side-to-side movement

Front 14

Describe gray matter

Back 14

Dull colored because it has little myelin. Site of synaptic contact between neurons, so it's the site of neural integration in the spinal cord

Front 15

Describe white matter

Back 15

Has an abundance of myelin. Composed of bundles of axons called tracts that carry signals from one part of the CNS to another

Front 16

Describe the visible structure of gray matter in the spinal cord

Back 16

Looks like a butterfly. Has two posterior/dorsal horns and two anterior/ventral horns. Central canal is often collapsed in adults

Front 17

Describe the anterior and posterior roots of a spinal nerve

Back 17

Anterior: the anterior horns of gray matter contain large somas of the somatic motor neurons. Axons from these somatic motor neurons exit by way of the anterior root and go to the skeletal muscles

Posterior: carries sensory nerve fibers, which enter the posterior horn and sometimes synapse with an interneuron there

Front 18

What is another term for the 3 pairs of columns in the white matter, consisting of bundles of axons?

Back 18

Funiculi

Front 19

Each funiculi/column is subdivided into...(2 synonymous terms)

Back 19

tracts/fascilculi

Front 20

What do ascending tracts carry?

Back 20

sensory information

Front 21

What do descending tracts carry?

Back 21

motor impulses

Front 22

When tracts decussate so that the origin and destination are on opposite sides of the body, we say they are _______________ to each other

Back 22

contralateral

Front 23

How many neurons do sensory signals travel across? Describe each

Back 23

3

First-order neuron: origin to spinal cord or brainstem

Second-order neuron: spinal cord or brainstem to thalamus/gateway

Third-order neuron: thalamus/gateway to sensory region of cerebral cortex

Front 24

What are the names of the three pairs of funiculi of white matter?

Back 24

anterior, lateral, posterior

Front 25

Name the 6 ascending tracts

Back 25

gracile fasciculus, cuneate fasciculus, spinothalamic, spinoreticular, posterior spinocerebellar, anteriorspinocerebellar

Front 26

What sensory information does gracile fasciculus carry?

Back 26

sensation of limb and trunk position and movement, deep touch, visceral pain, and vibration below T6

Front 27

What sensory information does cuneate fasciculus carry?

Back 27

same as gracile fasciculus but above T6

Front 28

What sensory information does the spinothalamic tract carry?

Back 28

sensations of light touch, tickle, itch, temperature, pain, and pressure

Front 29

What sensory information does the spinoreticular tract carry?

Back 29

sensation of pain from tissue injury

Front 30

What sensory information does the posterior spinocerebellar tract carry?

Back 30

feedback from muscles (proprioreception)

Front 31

What sensory information does the anterior spinocerebellar tract carry?

Back 31

same as posterior spinocerebellar. Proprioreception

Front 32

Name the 7 descending (motor) tracts

Back 32

lateral corticospinal, anterior corticospinal

tectospinal

lateral reticulospinal, medial reticulospinal

lateral vestibulospinal, medial vestibulospinal

Front 33

What motor information do the lateral and anterior corticospinal tracts relay?

Back 33

fine control of limbs

Front 34

What motor information does the tectospinal tract relay?

Back 34

reflexive head turning in response to visual and auditory stimuli

Front 35

What motor information do the lateral and medial reticulospinal tracts relay?

Back 35

balance and posture; regulation of awareness of pain

Front 36

What motor information does the lateral vestibulospinal tract relay?

Back 36

balance and posture

Front 37

What motor information does the medial vestibulospinal tract relay?

Back 37

control of head position

Front 38

A short distance away from the spinal cord the, _______________ swells into the _________________, which contains the neurosomas of sensory neurons

Back 38

posterior root, posterior root ganglion

Front 39

When the dorsal and ventral roots merge, they form the spinal nerve proper, which is a __________ nerve because it carries sensory and motor signals

Back 39

mixed