spinal cord Flashcards
1
Q
what grooves are the spinal cord divided left and right into?
A
anterior median fissure and posterior median sulcus
2
Q
what is gray matter composed of mainly in the internal spinal cord?
A
neuron cell bodies
3
Q
what is white matter composed of mainly in the internal spinal cord?
A
myelinated axons
4
Q
what is the central canal or the spinal cord filled with?
A
cerebrospinal fluid
5
Q
what is the gray commissure the site of?
A
axons cross from one side of CNS to other
6
Q
what type of nuclei does the posterior gray horns contain?
A
sensory nuclei
7
Q
what type of nuclei does the lateral gray horns contain?
A
autonomic motor nuclei
8
Q
what type of nuclei does the anterior gray horns contain?
A
somatic motor nuclei
9
Q
what do cell bodies of interneurons in the posterior gray horns receive and process?
A
incoming sensory input
10
Q
what do the sensory nuclei of the posterior gray horns contain?
A
cell bodies of spinal cord interneurons
11
Q
what do the cell bodies of the lower motor neurons located in the anterior gray horns send?
A
somatic motor output towards skeletal muscles
12
Q
what does the somatic motor nuclei of the anterior gray horns contain?
A
cell bodies of lower motor neurons
13
Q
what does the autonomic motor nuclei of the lateral gray horns contain?
A
cell bodies of preganglioic neurons
14
Q
what do the cell bodies of preganglionic neurons located in the lateral gray horns send?
A
autonomic motor output towards glands, cardiac and smooth muscles
15
Q
what is anterior white commissure the site of?
A
where axons cross from one side of CNS to other
16
Q
what is white matter in the spinal cord subdivided into?
A
white columns
17
Q
what do white columns contain
A
ascending and descending spinal cord tracts= bundles of axons
18
Q
what do ascending tracts conduct?
A
sensory input to brain
19
Q
what do descending tracts conduct?
A
motor output away from the brain
20
Q
what does the tract name often reveal?
A
origin, destination and white matter location
21
Q
what are the posterior white columns?
A
- fasciculus gracilis
- fasciculus cuneatus
22
Q
what sensory info does fasciculus gracilis/cuneatus tracts conduct?
A
- fine touch
- vibration
- pressure
- proprioception (conscious)
23
Q
what are the lateral white columns?
A
- lateral spinothalamic
- anterior and posterior spinocerebellar
- lateral corticospinal
24
Q
what sensory info does the lateral spinothalamic tract conduct?
A
pain and temp
25
what sensory info does the anterior and posterior spinocerebellar tracts conduct?
proprioception (unconscious)
26
where are the anterior and posterior spinocerebellar tracts located?
lateral white columns
27
what are the anterior white columns?
- anterior corticospinal
| - anterior spinothalamic
28
what sensory info does the lateral corticospinal tract conduct?
-somatic motor output that controls the skeletal muscles of the limbs
29
is the lateral corticospinal tract an ascending or descending tract?
descending
30
what sensory info does the anterior corticospinal tract conduct?
somatic motor output that controls the skeletal muscles of the axial skeleton (neck and trunk)
31
is the anterior corticospinal tract an ascending or descending tract?
descending
32
are the anterior and posterior spinocerebellar ascending or descending?
ascending
33
what ascending tract is responsible for crude touch and pressure?
anterior spinothalamic tract
34
what do sensory pathways connect?
receptors to brain
35
what do motor pathways connect?
brain to skeletal muscles
36
what do somatosensory pathways conduct?
general sensory input from receptors to brain
37
how many relay neurons are involved in the somatosensory pathways?
3
38
what 3 relay neurons are involved in the somatosensory pathways?
first/second/third-order neurons
39
what are the three main somatosensory pathways?
- spinothalamic pathway
- posterior column pathway
- spinocerebellar pathway
40
what does the spinothalamic pathway conduct?
sensations of crude touch, pressure, pain and temp
41
where do the first-order neurons of the spinothalamic pathway conduct sensory input from receptors into?
posterior gray horns
42
where do the second-order neurons of the spinothalamic pathway conduct sensory input to?
thalamus
43
how does sensory info ascend the spinal cord in the spinothalamic pathway?
- anterior spinothalamic tract
| - lateral spinothalamic tract
44
where does the third-order neurons of the spinothalamic pathway conduct sensory input?
to the primary somatosensory cortex
45
what does the posterior column pathway conduct?
sensations of fine touch, pressure, vibration and proprioception
46
where do first-order neurons conduct sensory input into in the posterior column pathway?
into the posterior gray horns and up to the medulla oblongata
47
what tracts does sensory input ascend in the first-order neurons of the posterior column pathway?
-fasciculus gracilis or cuneatus tracts
48
where do first-order neurons synapse with second-order neurons in the posterior column pathway?
medulla oblongata
49
where does sensory input get conducted in second-order neurons of the posterior column pathway?
thalamus
50
where do third-order neurons of the posterior column pathway conduct sensory input?
primary somatosensory cortex
51
what does the spinocerebellar pathway conduct?
sensations of proprioception
52
where does the first-order neurons of the spinocerebellar pathway conduct sensory input to?
into the posterior gray horns
53
where do the first-order neurons of the spinocerebellar pathway synapse with second-order neurons?
within a sensory nucleus
54
where do second-order neurons of the spinocerebellar pathway conduct sensory input?
cerebellum
55
what tracts does sensory input ascend in the second-order neurons of the spinocerebellar pathway?
anterior or posterior spinocerebellar tract
56
what do the somatic motor pathways conduct?
somatic motor output from the primary cortex to a skeletal muscle
57
how many relay neurons does the somatic pathways involve?
2
58
what are the two relay neurons of the somatic motor pathways?
- upper motor neuron
| - lower motor neuron
59
what are the two main somatic motor pathways?
- lateral corticospinal pathway
| - anterior corticospinal pathway
60
what does the lateral corticospinal pathway conduct?
the somatic motor output that controls the skeletal muscles of the limbs
61
what do the upper motor neurons of the lateral corticospinal pathway conduct?
somatic motor output from the primary motor cortex to an anterior gray horn
62
what spinal tract does the somatic motor output from the upper motor neurons of the lateral corticospinal pathway descend?
lateral corticospinal tract
63
where does the upper motor neurons of the lateral corticospinal pathway synapse with lower motor neurons?
in a motor nucleus
64
what do lower motor neurons of the lateral corticospinal pathway conduct?
somatic motor output to skeletal muscles of the limbs
65
what does the anterior corticospinal pathway conduct?
somatic motor output that controls the skeletal muscles of the axial skeleton (head, neck, trunk)
66
what do the upper motor neurons of the anterior corticospinal pathway conduct?
somatic motor output from the primary motor cortex to an anterior gray horn
67
what spinal tract does the somatic motor output from the upper motor neurons of the anterior corticospinal pathway descend?
anterior corticospinal tract
68
what do lower motor neurons of the anterior corticospinal pathway conduct?
somatic motor output to skeletal muscles of the neck and trunk
69
what are spinal reflex arcs?
neural pathways that produce rapid, predictable, involuntary somatic or autonomic reflex response to a stimulus
70
what do spinal cord injuries result in?
sensory and/or motor losses at or below the level of injury
71
what does damage to the posterior gray horns or ascending spinal cord tracts lead to?
loss of sensation
72
what does damage to the anterior gray horns or corticospinal tracts lead to?
spastic or flaccid paralysis
73
what does a complete transection of the spinal cord result in?
a loss of all sensations and voluntary movement
74
what does a transection in the cervical region of the spinal cord result in?
quadraplegia
75
what does a transection in the thoracic or lumbar region of the spinal cord result in?
paraplegia
76
what is spinal shock?
a transient period of complete sensory and motor loss, and a loss of all reflexes below level of lesion, reflex activity gradually returns
77
what is spastic paralysis?
- loss of voluntary movement
| - reflex activity intact but abnormal
78
what is flaccid paralysis?
loss of voluntary movement and reflex activity
79
is flaccid paralysis caused by damage to the upper or lower motor neurons?
lower
80
is spastic paralysis caused by damage to the upper or lower motor neurons?
upper
81
approx how long is the spinal cord?
42cm long
82
approx how wide is the spinal cord?
14mm wide
83
when does the spinal cord end?
L1-L2 of vertebral column in adults and L4 in infants
84
what is the cone shaped structure that the spinal cord terminates at?
conus medullaris
85
what is the spinal cord anchored to the coccyx by?
filum terminale
86
how many regions are there in the vertebral column?
5
87
how many segments are there in the vertebral column?
31
88
how many pairs of cervical nerves are there?
8
89
how many pairs of thoracic nerves are there?
12
90
how many pairs of lumbar nerves are there?
5
91
how many pairs of sacral nerves are there?
5
92
how many pairs of coccygeal nerves are there?
1
93
what are the five regions starting from closest to the head down?
- cervical
- thoracic
- lumbar
- sacral
- coccyx
94
what do spinal nerves branch to form?
peripheral nerves
95
what type of nerves are spinal nerves?
mixed nerves that contain the axons of sensory and motor (somatic and automatic) neurons
96
are dorsal roots motor or sensory?
sensory
97
are ventral roots motor or sensory?
motor
98
what do dorsal roots contain?
axons of sensory neurons
99
what do ventral roots contain?
axons of motor neurons (somatic and autonomic)
100
what do dorsal root ganglion contain?
cell bodies of sensory neurons
101
what is the collection of roots beyond the conus medullaris called?
cauda equina
102
how is the spinal cord protected from mechanical forces?
- vertebral column
- CSF
- spinal meninges
103
what is CSF withdrawn from the spinal cord in a lumbar puncture used for?
diagnostic testing or reducing intracranial pressure
104
what is a lumbar puncture (spinal tap)?
involves the insertion of a needle into the subarachnoid space beyond L3
105
how is the outer dura mater separated from the vertebral column?
epidural space
106
what is the site of anaesthetic administration?
epidural space
