the spinal cord

Question 1

what are the regions in spinal column

Answer 1

cervical, thoracic, lumbar, sacral

Question 2

where does the cervical region serve

Answer 2

neck

Question 3

where does thoracic region serve

Answer 3

thorax

Question 4

where does lumbar region serve

Answer 4

lower back

Question 5

where does sacral region serve

Answer 5

butt

Question 6

how many vertebra

Answer 6

30

Question 7

how can we move if we have vertebra

Answer 7

jelly donuts separate vertebra (tough tissue and thick liquid)

Question 8

what are the breakdowns for vertebra

Answer 8

7 cervical vertebrae (C1 - C7)
12 thoracic vertebrae (T1 - T12)
5 lumbar vertebrae (L1 - L5)
5 sacral vertebrae (S1 - S5) [fused]
Coccyx (tailbone)

Question 9

where is c1 attatched to

Answer 9

bottom of skull

Question 10

how do nerves leave vertebra

Answer 10

through the holes, out both sides

Question 11

where does SC end

Answer 11

at conus medullaris which is L1 region

Question 12

what is the cauda equina

Answer 12

the dangling nerves beyond the end of the SC

Question 13

what holds the dangling nerves in the cauda equina

Answer 13

thecal sac

Question 14

what is the thecal sac made out of and what is it filled with

Answer 14

dura matter and filled with CSF

Question 15

what is the spinal nerve breakdown

Answer 15

8 cervical spinal nerves (c1 - c8)
12 thoracic spinal nerves (t1 - 12)
5 lumbar spinal nerves (l1 - l5)
5 sacral spinal nerves (S1 - S5)
1 coccygeal spinal nerve

Question 16

where do nerves go in relation to vertebra

Answer 16

Nerve goes under vertebra expect for cervical spinal nerves where they go above and 8 is below C7

Question 17

where do the sacral and coccygeal perforate and where do they go

Answer 17

the sacrum from back to front and go down the legs

Question 18

where is the spinal cord widest and why

Answer 18

cervical and lumbosacral regions due to increase in LMN for arms/legs

Question 19

what are the two fissures in the spinal cord and what are the differences in them

Answer 19

anterior median fissure –> shallow but wide separation
posterior median fissure –> deep but thin fissure (tissue adhered to itself)

Question 20

what are the sulci on the SC and what occurs at these places

Answer 20

anterolateral sulcus –> motor roots exit
posterolateral sulcus –> sensory roots enter

Question 21

what is the differences between tracts and columns

Answer 21

tracts are fiber bundles with common functions

columns contain multiple tracts

Question 22

what info is in ascending tracts

Answer 22

sensory

Question 23

what info is in descending tracts

Answer 23

motor info

Question 24

how do tracts change throughout the spinal cord

Answer 24

in size and shape but not relative position

Question 25

what are the descending tracts

Answer 25

corticospinal rubrospinal reticulospinal vestibulospinal tectospinal

Question 26

where does the corticospinal tract go to/from

Answer 26

from cerebral cortex to spinal cord

Question 27

how many corticospinal tracts are there and how do they differ

Answer 27

2 --> lateral (decussates), anterior (no decussation)

Question 28

how are the axons for each region arranges in corticospinal tract

Answer 28

sacral most lateral, cervical most medial

Question 29

where does the rubrospinal tract go to/from

Answer 29

from red nucleus to spinal cord

Question 30

what info does the corticospinal tract carry

Answer 30

main motor movement (UMN to LMN)

Question 31

how many rubrospinal tracts

Answer 31

1

Question 32

what does the rubrospinal tract do

Answer 32

regulate large muscle movement (esp arms)

Question 33

where does the reticulospinal tract go to/from

Answer 33

from reticular formation (part of BS) to spinal cord

Question 34

how many reticulospinal tracts are there and what are they

Answer 34

2: lateral and medial

Question 35

what does the reticulospinal tract do

Answer 35

modify pain perception (analgesic system)

Question 36

where does the vestibulospinal tract go to/from

Answer 36

from vestibular nuclei (in brain stem) to spinal cord

Question 37

how any vestibulospinal tracts are there

Answer 37

1

Question 38

what does the vestibulospinal tract do

Answer 38

activate quick movements due to body postion changes

Question 39

where does the tectospinal tract go to/from

Answer 39

from superior colliculus (tectum in midbrain) to spinal cord

Question 40

what does the tectospinal tract do

Answer 40

coordinate eye and head movements

Question 41

how many tetcospinal tracts

Answer 41

1

Question 42

where do the 1º neurons for sensory live

Answer 42

dorsal root ganglion

Question 43

what are the ascending tracts

Answer 43

dorsal white column tracts spinothalamic tracts spinocerebellar tracts

Question 44

where do the dorsal columns go to/from

Answer 44

from spinal cord to medial lemniscus

Question 45

what is another name for the dorsal column

Answer 45

medial lemniscal system

Question 46

what info is carried in the dorsal columns

Answer 46

touch, vibration, positon

Question 47

what are the sides of the dorsal columns and where are they

Answer 47

fasciculus gracilis --> medial fascilus cuneatus --> lateral

Question 48

how are the axons for each region arranges in dorsal columns

Answer 48

cervical most lateral, sacral most media

Question 49

where does the spinothalamic tracts go to/from

Answer 49

from spinal cord to thalamus

Question 50

how many spinothalamic tracts are there and what

Answer 50

2: lateral, anterior

Question 51

what info is carried in spinothalamic tracts

Answer 51

sharp pain, temperature

Question 52

how are the axons for each region arranges in spinothalamic tract

Answer 52

Sacral most lateral, cervical most medial

Question 53

where does the spinocerebellar tracts go to/from

Answer 53

from sc to cerebellum

Question 54

what info is carried in spinocerebellar tracts

Answer 54

motor control, state, position

Question 55

how many spinocerebellar tracts and what are they

Answer 55

2: posterior and anterior

Question 56

how many horns in grey matter and what are they

Answer 56

4 2 sensory in dorsal 2 motor in ventral

Question 57

what is the difference between spinal nerves and roots

Answer 57

Spinal nerves are combo of dorsal and ventral roots on same side of body

Question 58

what are ventral roots

Answer 58

Myelinated axons coming from the lower motor neurons that innervate body’s muscles, organs and circulatory system for motor output

Question 59

what are dorsal roots

Answer 59

myelinated axons that bring sensory input into CNS from receptors Info about pressure, temperature and pain

Question 60

what are the spinal nerve types

Answer 60

somatic efferents, visceral efferents, somatic afferents, visceral afferents

Question 61

what do somatic efferents control

Answer 61

voluntary movment

Question 62

what do visceral efferents control

Answer 62

involuntary smooth muscle motor movement and secretion from autonomic nervous system

Question 63

what do somatic afferents do

Answer 63

convey stretch and touch info from skin, joints and muscles

Question 64

what do visceral afferents do

Answer 64

convey info from internal organs

Question 65

where do cervical nerves go to

Answer 65

neck, arms, shoulder, upper back

Question 66

where do thoracic nerves go to

Answer 66

chest, abdomen, back

Question 67

where do lumbar nerves go to

Answer 67

hips, low back, legs, feet

Question 68

where do sacral nerves go to

Answer 68

butt, perineum, crotch, back of leg, feet

Question 69

where does the coccygeal nerve go to

Answer 69

tailbone

Question 70

what activates mechanoreceptor neutires

Answer 70

all somatic sensations (but tissue damage only activate in extreme conditions)

Question 71

what somatic sensations are there

Answer 71

pressure, vibration, hair deflection

Question 72

what activates nociceptors

Answer 72

noxious stimuli (tissue damage)

Question 73

where do mechanoreceptors decussate

Answer 73

medulla (brain stem)

Question 74

how do mechanoreceptors ascend in the sc

Answer 74

ipsilaterally

Question 75

where is the first mechanoreceptor synapse

Answer 75

medulla (brain stem)

Question 76

where do nociceptive cells decussate

Answer 76

spinal cord

Question 77

where is the first nociceptive synapse

Answer 77

dorsal horn

Question 78

how do nocicpetive ascend in the sc

Answer 78

contralaterally

Question 79

what are the types of 2º nocipetive neurons

Answer 79

Nociceptive specific cells Wide range dynamic cells

Question 80

what is the majority 2º nociceptive cell

Answer 80

nociceptive specific cells

Question 81

where are Nociceptive specific cells located

Answer 81

superficial parts of dorsal horn

Question 82

what do Nociceptive specific cells respond to

Answer 82

noxious stimuli only

Question 83

who does Nociceptive specific cells recetive synaptic connections from

Answer 83

1º noci cells

Question 84

where are wide range dynamic cells located

Answer 84

deep intermediate parts of dorsal horn

Question 85

what do wide range dynamic cells respond to

Answer 85

noxious stimuli and pressure

Question 86

what does wide range dynamic cells receptive synaptic connections from

Answer 86

noci cells and mechanoreceptors

Question 87

where does the spinothalamic tract project to (all steps)

Answer 87

to medial thalamus which projects to both somatosensory and associative cortices

Question 88

what is the associative cortex

Answer 88

interacts with other parts of brain to get meaning/quality of pain

Question 89

where does the neospinothalamic tract go

Answer 89

lateral thalamus which projects to somatosensory cortex

Question 90

what are the differences between UMN and LMN

Answer 90

UMN live in motor cortex and project axons to LMN, they are the origins of motor commands LMN live in ventral horns and control muscles

Question 91

what percent of UMN decussate and where

Answer 91

80-90% at pyramidial decussation in lower medulla

Question 92

what corticospinal tract decussates and what does not

Answer 92

lateral decussate and anterior does not

Question 93

what are intrafusal fibers

Answer 93

sensory component in muscle that doesn’t contract but contains a sensory stretch receptor

Question 94

what are extrafusal fibers

Answer 94

bulk of the muscle that is the sensory component which moves the muscle

Question 95

how do reflexes work

Answer 95

When the intrafusal fibers are stretched, the DRG sensory neuron goes onto the LMN to activate the extrafusal fiber of the same muscle to contract it Since muscles exist in antagonistic pairs, the sensory afferents also activate inhibitory interneurons that interact with a different LMN to suppress the extrafusal fibers of the opposite muscle

Question 96

what are signs of lower motor lesions

Answer 96

flaccid paralysis of involved muscles, muscular atrophy (because muscles don’t get activity so it degrades), diminished or absent reflexes

Question 97

what are signs of upper motor lesions

Answer 97

spastic paralysis (bc LMN are still alive so can act on their own spasms), little/no muscle atrophy, hyperactive reflexes