Spinal Cord Flashcards

1
Q

dorsal root ganglia (DRG)

A

*contain the cell bodies of sensory neurons
*NO SYNAPSES in the DRG

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2
Q

dorsal root (of a spinal segment)

A

*axons of sensory neurons (with cell bodies in DRG)
*afferents

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3
Q

ventral root (of a spinal segment)

A

*axons of motor neurons innervating skeletal muscles
*efferents

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4
Q

gray matter

A

*enriched with nerve cell bodies (soma)
*stains lightly on myelin stain

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5
Q

white matter

A

*enriched with axons
*stains darkly on myelin stain

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6
Q

gray and white matter organization in the spinal cord

A

*gray matter (cell bodies) on the INSIDE
*white matter (axons) on the OUTSIDE

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7
Q

organization of gray matter in the spinal cord

A

1) posterior/dorsal horn (sensory - cell bodies of neurons for pain & temp)
2) anterior/ventral horn (motor - cell bodies of lower motor neurons)
3) lateral horn (cell bodies of sympathetic nervous system; only found in the thoracic region)

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8
Q

organization of white matter in the spinal cord

A

1) lateral corticospinal tract (motor axons; descending)
2) posterior/dorsal column (sensory axons for vibration and proprioception; ascending)
3) spinothalamic tract (sensory axons for pain and temperature; ascending)

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9
Q

spinal segment

A

the portion of the spinal cord that forms a specific spinal nerve

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10
Q

spinal nerve

A

a mixed nerve formed by the joining of the dorsal root (sensory) and the ventral root (motor)

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11
Q

anterior horn

A

contains cell bodies of LOWER MOTOR NEURONS

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12
Q

posterior/dorsal horn

A

contains cell bodies of sensory neurons for pain and temperature (location of first synapse for the spinothalamic tract)

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13
Q

spinothalamic tract - general function

A

carries ascending sensory information about PAIN, TEMPERATURE, and CRUDE TOUCH

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14
Q

spinothalamic tract - pathway

A

1) first neuron enters the spinal cord, immediately synapsing in the posterior/dorsal horn, and decussates
2) second neuron ascends all the way up the spinal cord, through the brainstem, and into the thalamus, synapsing in the VPL nucleus
3) third neuron carries the info from the VPL to the somatosensory cortex

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15
Q

spinothalamic tract - level of decussation

A

decussates at the level of the spinal cord that it enters into

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16
Q

damage to spinothalamic tract leads to

A

contralateral loss of pain and temp

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17
Q

dorsal column-medial lemniscus - general function

A

carries ascending sensory information about VIBRATION, PROPRIOCEPTION, and FINE TOUCH

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18
Q

dorsal column-medial lemniscus - pathway

A

1) first neuron enters the spinal cord and ascends (on the ipsilateral side) all the way up to the caudal medulla, where it synapses in either the nucleus gracilis or the nucleus cuneatus
2) second neuron (after synapse) decussates in the caudal medulla and ascends through the brainstem, synapsing in the VPL nucleus of the thalamus
3) third neuron carries info from the VPL to the somatosensory cortex

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19
Q

dorsal column-medial lemniscus - level of decussation

A

decussates in the caudal medulla

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20
Q

dorsal column-medial lemniscus - damage to the spinal cord causes

A

IPSILATERAL loss of propriception/vibration

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21
Q

dorsal column-medial lemniscus - damage to the brainstem causes

A

CONTRALATERAL loss of proprioception/vibration

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22
Q

corticospinal tract - general function

A

carries descending MOTOR information from the cortex to skeletal muscles

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23
Q

corticospinal tract - pathway

A

1) first neuron travels from cortex down through brainstem, decussating in the caudal medulla (decussation of pyramids) and continues to descend through the spinal cord, synapsing in the anterior horn at the level of the spinal cord where it wants to create an activity
2) second neuron carries the signal from the anterior horn out to the periphery to innervate the muscle

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24
Q

corticospinal tract - level of decussation

A

caudal medulla (decussation of pyramids)

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25
Q

corticospinal tract - damage anywhere from brainstem up to cortex causes

A

CONTRALATERAL motor loss

26
Q

corticospinal tract - damage to the spinal cord causes

A

IPSILATERAL motor loss

27
Q

fasciculus gracilis

A

the dorsal column pathway (more medial) that carries proprioception and vibration from the lower limbs

28
Q

fasciculus cuneatus

A

the dorsal column pathway (more lateral) that carries proprioception and vibration from the upper limbs

29
Q

dermatome

A

a region of skin innervated by an individual spinal nerve that in turn synapses in the corresponding spinal segment

30
Q

dermatome of nipple region

A

T4

31
Q

dermatome of umbilicus

A

T10

32
Q

C5 dermatome

A

shoulder

33
Q

C6 dermatome

A

lateral forearm (in anatomical position)

34
Q

C7 dermatome

A

middle digit

35
Q

C8 dermatome

A

fourth and fifth digits

36
Q

T1 dermatome

A

medial forearm (in anatomic position)

37
Q

L4 dermatome

A

anteromedial leg (below the knee)

38
Q

L5 dermatome

A

anterior lateral leg (below knee) and dorsum of foot

39
Q

S1 dermatome

A

small toe, lateral foot, calf

40
Q

S2-S4 dermatome

A

saddle-like distribution in the perineal area

41
Q

L4 myotome

A

mediates leg extension and patellar reflex

42
Q

L5 myotome

A

dorsiflexion at the ankle

43
Q

S1 myotome

A

mediates plantar flexion at the ankle & the achilles tendon reflex

44
Q

C5 myotome

A

mediates arm abduction

45
Q

C5-C6 myotome

A

mediates flexion at the elbow and the biceps tendon reflex

46
Q

C6 myotome

A

wrist extension

47
Q

C7 myotome

A

elbow extension and the triceps reflex

48
Q

functional components of the spinal nerve

A
  1. general somatic afferents (GSA)
  2. general visceral afferent (GVA)
  3. general visceral efferent (GVE)
  4. general somatic efferent (GSE)
49
Q

how many spinal nerves are there

A

31 spinal nerves

50
Q

where does the spinal cord end (conus medullaris)

A

vertebral level L1/L2

51
Q

cauda equina

A

nerve fibers that continue to run down in the vertebral column after the spinal cord ends

52
Q

spinal cord enlargements

A
  1. cervical enlargement (C5-T1)
  2. lumbar enlargement (L1-S2)
53
Q

coverings of the spinal cord

A

dura, arachnoid, and pia mater

54
Q

epidural space in the spinal cord

A

*REAL space between the vertebral column and the dura
*used as a site for administering analgesics/anasthetics

55
Q

subdural space in spinal cord

A

a POTENTIAL space between the dura and the arachnoid

56
Q

subarachnoid space in the spinal cord

A

*a REAL space between the arachnoid and the pia mater

57
Q

blood supply to the spinal cord - general

A

1 anterior spinal artery (majority of blood) and 2 posterior spinal arteries

58
Q

Rexed laminae

A

distinct layers of the gray matter in the spinal cord

59
Q

sacral spinal cord (appearance)

A

predominantly gray matter

60
Q

lumbar spinal cord (appearance)

A

more white matter compared to sacral region

61
Q

thoracic spinal cord (appearance)

A

lots of white matter & lateral horn

62
Q

cervical spinal cord (appearance)

A

predominantly white matter; very little gray matter