Spinal Cord Anatomy

Question 1

gray matter =

Answer 1

cell bodies

Question 2

gray matter is composed mostly of

Answer 2

neuronal cell bodies, capillaries, and some support cells

Question 3

dorsal white matter column boundaries

Answer 3

medially - dorsal median sulcus

laterally - dorsolateral sulcus

Question 4

dorsal white matter column consists of

Answer 4

fasciculus gracilis and fasciculus cuneatus

Question 5

dorsal white matter column contains

Answer 5

only sensory ascending tracts

Question 6

lateral white matter column location

Answer 6

between dorsal and ventral roots

Question 7

lateral white matter column contains

Answer 7

ascending and descending fiber tracts

both sensory and motor fibers

Question 8

ventral white matter column location

Answer 8

between ventral roots and ventral median fissure

Question 9

ventral white matter column contains

Answer 9

both ascending and descending sensory and motor tracts

Question 10

how many pairs of spinal nerves

Answer 10

31 pairs

Question 11

spinal cord segments

Answer 11

8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

Question 12

which spinal cord segments are part of the lumbar and cervical enlargements

Answer 12

cervical - C5-T1

lumbar - L2-S2

Question 13

4 types of neurons found in spinal cord gray matter

Answer 13

1. interneurons
2. motor neurons
3. sensory neurons
4. preganglionic autonomic neurons

Question 14

location of interneurons

Answer 14

everywhere

Question 15

characteristics of interneurons

Answer 15

short axons, receive info, send info a short distance, help shape CNS function

Question 16

location of motor neurons

Answer 16

ventral horn only

Question 17

characteristics of motor neurons

Answer 17

alpha - striated
gamma - special receptors in muscle
innervate skeletal muscle fibers

Question 18

location of sensory neurons

Answer 18

dorsal horn only

Question 19

characteristics of sensory neurons

Answer 19

axons form ascending sensory white matter tracts

others integrate

Question 20

location of preganglionic motor neurons

Answer 20

lateral horns (T1-L2 and S2-S4)

Question 21

characteristics of preganglionic motor neurons

Answer 21

axons form part of output pathway of autonomic nervous system

Question 22

4 types of dorsal horn nuclei

Answer 22

1. substantia gelatinosa
2. nucleus proprius
3. nucleus dorsalis
4. visceral afferent nucleus

Question 23

location/function of substantia gelatinosa

Answer 23

location - apex of dorsal horn
function - pain modulation

Question 24

location/function of nucleus proprius

Answer 24

location - dorsal horn (largest nucleus)
function - transmission of pain and temperature

Question 25

location/function of nucleus dorsalis (clark's nucleus)

Answer 25

``` location - medial base of dorsal horn, spinal cord segments C8-L3 function - related proprioceptive info ```

Question 26

location/function of visceral afferent nucleus

Answer 26

``` location - lateral to nucleus dorsalis in dorsal horn, spinal cord segments T1-L2, S2-4 function - receives visceral sensory dorsal root fibers (input part of ANS) ```

Question 27

which spinal cord segments contain a lateral horn

Answer 27

T1-L2 and S2-S4 (forms intermediolateral cell column)

Question 28

what kind of neurons are located in the lateral horn

Answer 28

visceral preganglionic motor neurons

Question 29

function of visceral preganglionic motor neurons

Answer 29

part of the ANS

Question 30

why kind of neurons are located in the ventral horn

Answer 30

1. alpha motor neurons (large) 2. gamma motor neurons (small) 3. interneurons

Question 31

function of ventral horn neurons

Answer 31

motor

Question 32

names of 3 white matter bundles not part of 3 major white matter columns

Answer 32

1. ventral white commissure 2. dorsolateral tract of lissauer 3. fascicles proprius

Question 33

function of ventral white commissure

Answer 33

pain and temperature | allows sensory pain info to cross midline of spinal cord

Question 34

function of dorsolateral tract of lissauer

Answer 34

short ascending and descending fibers carrying info relating to pain

Question 35

function of fasciculus proprius

Answer 35

short ascending and descending fibers that connect spinal segments and are important for intersegmental reflexes

Question 36

syringomyelia

Answer 36

Causes a lesion around the central canal of the spinal cord Usually present in the cervical cord region (The lesion starts centrally affecting medial structures then grows out laterally)

Question 37

syringomyelia destroys

Answer 37

ventral white commissure and the alpha and gamma motor neurons in the ventral gray matter

Question 38

spina bifida

Answer 38

Congenital malformation of neural tube development | Results in incompletely formed spinal cord and sometimes malformations of vertebral segments

Question 39

signs/symptoms of spina bifida

Answer 39

varying degrees of paralysis, absence of skin sensation, poor or absent bowel and/or bladder control Curvature of spine (scoliosis)

Question 40

4 presentations of spina bifida

Answer 40

1. spina bifida occulta 2. meningocele 3. meningomyelocele 4. rachischisis/anencaphalic

Question 41

beginning/end of spinal cord

Answer 41

Begins: foramen magnum Ends: approximately L2 in adults

Question 42

Spinal Cord Neural Segment

Answer 42

Part of spinal cord which receives or gives dorsal and ventral rootlets for a single pair of spinal nerves

Question 43

Lesion in Gray Matter

Answer 43

Impairments are segmental: only affecting structures innervated by that particular section of grey matter Ex) Lesion in gray matter of C5 → you impair ONLY the muscles innervated by C5

Question 44

Lesion in White Matter

Answer 44

The lesion in white matter affects all functions of all structures below the level of the lesion Destroys function of cell bodies that they originated from White matter spreads Ex) Complete lesion of C5 → paralysis in every section the tract is heading to below