Spinal Cord Flashcards
(130 cards)
1
Q
What does the CNS consist of?
A
the forebrain
the brainstem
the spinal cord
2
Q
What is the forebrain comprised of?
A
the cerebral hemispheres
the olfactory bulb
the hypothalamus
the diencephalon
3
Q
What does the brainstem consist of?
A
the midbrain (mesencephalon)
the hindbrain (rhombencephalon)
4
Q
What parts of the CNS does the spinal cord contain?
A
sensory neurons that receive sensation from the sensory receptors
motor neurons that control muscles
long tracts connecting the spinal cord with the brain
the preganglionic nuclei of the autonomic nervous system
pattern generators for complex movements such as running at different speeds
5
Q
What is the spinal cord?
A
a long cylindrical structure extending from the base of the skull to the first lumbar vertebra in the human
6
Q
Where is the spinal cord noticeably thicker?
A
in the regions that are connected to the upper and lower limb
7
Q
What is in a transverse section of the spinal cord?
A
A central butterfly-shaped area of grey matter is surrounded by white matter
8
Q
The gray matter is divided into:
A
ventral horn
dorsal horn
9
Q
The white matter is divided into:
A
3 funiculi (columns):
the dorsal funiculus
the lateral funiculus
the ventral funiculus
10
Q
The gray matter can be further subdivided into a series of layers called:
A
the laminae of Rexed
11
Q
What layers form the dorsal horn?
A
Layer 1
Layer 2
Layer 3
Layer 4
12
Q
What is the dorsal horn related to?
A
sensory input
13
Q
What layers form the ventral horn?
A
Layer 7
Layer 8
Layer 9
14
Q
What does the ventral horn have functions to?
A
the motor system
15
Q
What is located at lamina 9?
A
the limb and trunk motor neurons
16
Q
What lamina is found between the ventral and dorsal horns?
A
lamina 5
17
Q
What is lamina 5 the site of?
A
pattern generators for limb movements
18
Q
What lamina is small and not present at all levels?
A
lamina 6
19
Q
What does the spinal cord receive sensory information from?
A
the skin, joints, and internal organs
20
Q
The motor neurons in the spinal cord connect with and initiate activity in:
A
the muscles, blood vessels, and internal organs
21
Q
The brain sends what to control motor neurons in the SC
A
nerve fiber bundles (tracts)
22
Q
The mammalian spinal cord is made up of how many distinct anatomical and functional regions
A
6
23
Q
what is the prebrachial anatomical/functional SC region for?
A
the neck
24
Q
what is the brachial anatomical/functional SC region for?
A
the forelimb
25
what is the postbrachial anatomical/functional SC region for?
sympathetic outflow
26
what is the crural anatomical/functional SC region for?
lower limb
27
what is the postcrural anatomical/functional SC region for?
pelvic parasympathetic outflow
28
what is the caudal anatomical/functional SC region for?
the tail
29
What is the descending order of the anatomical/functional regions of the SC?
the neck
the forelimb
sympathetic outflow
lower limb
pelvic parasympathetic outflow
the tail
30
What spinal cord segments does the prebrachial region of the SC extend from?
C1 - C4
31
What spinal cord segments does the brachial region of the SC extend from?
C5 - T1
32
What spinal cord segments does the postbrachial region of the SC extend from?
T2 - L2
33
What spinal cord segments does the crural region of the SC extend from?
L3 - S1
34
What spinal cord segments does the
postcrural region of the SC extend from?
S2 - S4
35
What spinal cord segments does the caudal region of the SC extend from?
S5 - coccygeal segments
36
The spinal cord contains sophisticated pattern generators that can:
initiate different kinds of coordinated movements
37
Movement patterns generated in the spinal cord include
locomotion, posture, and balancing
38
Motor neurons in the SC initiate:
muscle fibre contraction and secretion of glands
39
What do motor neurons in the SC act as a final common pathway for?
motor function's central and peripheral neural pathways
40
What are the 2 major functional groups of the motor neurons in the SC?
somatic
autonomic
41
What do somatic motor neurons innervate?
skeletal (voluntary) muscle
42
What do autonomic motor neurons innervate?
smooth muscles and glands
43
Where are somatic motor neurons located in the SC?
the ventral horn of the gray of the SC in lamina 9
44
What type of neurons are somatic motor neurons in the spinal cord?
large multipolar neurons
45
What do somatic motor neurons in the spinal cord stain well with?
acetylcholinesterase markers
NeuN markers
46
Why are lamina 9 motor neurons large?
because they each support a very long axon that runs to supply the striated muscles of the axial skeleton (muscles of the neck, trunk, and tail) and the muscles of the upper and lower limbs
47
What does the axon of lamina 9 motor neurons supply?
the striated muscles of the axial skeleton (muscles of the neck, trunk, and tail)
the muscles of the upper and lower limbs
48
The motor neurons innervating axial muscles are present at:
all spinal cord levels
49
the large motor neurons innervating limb muscles are only present at:
the level of origin of the upper limb nerves (C5 to T1 spinal cord segments in the human)
the level of origin of the lower limb nerves (L3 to S1 spinal cord segments in the human)
50
The autonomic motor neurons of the spinal cord can be divided into what two separate groups?
the preganglionic motor neurons of the sympathetic nervous system
the preganglionic motor neurons of the pelvic parasympathetic system
51
the sympathetic preganglionic motor neurons are found where in the SC?
T2 - L2 spinal cord segments
52
What are the 2 parts of the parasympathetic system in the CNS?
Cranial parasympathetic system
Sacral parasympathetic system
53
Where in the SC are parasympathetic preganglionic motor neurons located?
S2 - S4 spinal cord segments
54
What connects each spinal nerve to the spinal cord?
A dorsal root
A ventral root
55
What does the ventral root contain?
the axons of motor neurons
56
What does the dorsal root contain?
sensory axons
57
The cell bodies of sensory axons in the SC are located where?
the dorsal root ganglion
58
What does the dorsal root ganglion form?
a swelling attached to the dorsal root
59
In the cervical region, the nerves are named for:
the vertebral body below their level of exit
60
C1 spinal nerve exits __ the C1 vertebrae
above
61
In the thoracic and lower vertebral levels, the emerging nerves are named for:
the vertebral body above their level of exit
62
T2 spinal nerve exits ___ the T2 vertebra
below
63
What nerve does the spinal nerve naming convention create a problem for?
The nerve between C7 and T1 vertebrae
64
The nerve between C7 and T1 vertebrae was called:
the C8 nerve
65
What level has a nerve but no vertebra
C8
66
How many cervical spinal nerves and vertebrae are there?
8 spinal nerves
7 vertebrae
67
How many thoracic spinal nerves and vertebrae are there?
12 spinal nerves
12 vertebrae
68
How many lumbar spinal nerves and vertebrae are there?
5 spinal nerves
5 vertebrae
69
How many sacral spinal nerves and vertebrae are there?
5 spinal nerves
5 vertebrae
70
How many coccygeal vertebrae is/are there?
1 to 2
71
The forelimb muscles are supplied by nerves from:
the brachial plexus
72
What spinal nerves form the brachial plexus?
C5
C6
C7
C8
T1
73
The hindlimb muscles are supplied by nerves from:
the lumbrosacral plexus
74
What spinal nerves form the lumbrosacral plexus?
L2
L3
L4
L5
S1
75
Each spinal nerve supplies a specific strip of skin from the ___ to the ___
1. middle of the back
2. ventral midline.
76
The skin area provided by a single spinal nerve is called:
a dermatome
77
Where do descending tracts arise?
the cerebral cortex
the brainstem
78
Most descending tracts cross where?
the brainstem
79
Most descending tracts descend in ___ of the SC?
the lateral funiculus
the ventral funiculus
80
Where do descending tracts terminate?
interneurons in laminae 5, 6, and 7
motor neurons in lamina 9
or both
81
Which descending tracts descend in the lateral funiculus?
corticospinal
rubrospinal
lateral reticulospinal
82
What are descending tracts of the lateral funiculus more concerned with?
the control of flexor movements
particularly distal parts of limbs
83
Which descending tracts descend in the ventral funiculus?
vestibulospinal
tectospinal
medial reticulospinal
84
What are descending tracts of the ventral funiculus more concerned with?
the control of extensor (postural) muscles of the trunk and proximal parts of limbs
85
The corticospinal tract travels from the ___ through the ___ to reach the ___, crossing to the opposite side.
1. motor cortex
2. internal capsule, pons, and pyramid
3. pyramidal decussation
85
The corticospinal tract travels from the ___ through the ___ to reach the ___, crossing to the opposite side.
1. motor cortex
2. internal capsule, pons, and pyramid
3. pyramidal decussation
86
Where does the corticospinal tract cross over to the opposite side?
the pyramidal decussation
87
Where is a common site of damage to the corticospinal tract in humans?
The internal capsule strip of white matter in the cerebral hemisphere
88
When the internal capsule is damaged, what can cause a stroke?
a haemorrhage or blood clot
89
What does an internal capsule stroke result in?
paralysis and stiffness in the muscles of the opposite side of the body
90
In primates, some corticospinal fibres make ___ with ___ in lamina 9
1. direct contact
2. motor neurons
91
Direct connections from the cerebral cortex to motor neurons are ___ in non– primate mammals.
rare or absent
92
The cortical control of limb movements in non–primate mammals is mainly based on what?
a major projection to lamina 5 in the spinal cord
93
What does lamina 5 contain?
a highly organized system of limb movement pattern generators
94
What brain stem centres send tracts to the spinal cord?
red nucleus (rubrospinal tract)
superior colliculus (tectospinal tract)
vestibular nuclei (vestibulospinal tracts) reticular nuclei (reticulospinal tracts)
95
What are the dorsal columns?
gracile fasciculus
cuneate fasciculus
96
Both the spinothalamic tracts and the dorsal columns (gracile and cuneate fasciculi) do what?
convey somatosensory information from one side of the body to the cerebral cortex of the opposite side via the thalamus.
97
What two ascending tracts in the spinal cord are basically chains of three neurons
the dorsal column
the spinothalamic tracts
98
In ascending SC tracts, the first neuron is:
a dorsal root ganglion cell
99
In ascending SC tracts, where does the central process of the first neuron enter?
the spinal cord
100
In ascending SC tracts, the axon of the second neuron ___ immediately
crosses the midline
101
In ascending SC tracts, the second neuron climbs to where?
the thalamus
102
In ascending SC tracts, the third neuron sends its axon from where to where?
from the thalamus
to the cerebral cortex
103
the central process of the first neuron in the spinothalamic system is:
short (its axon ascends for only a few spinal cord segments)
104
the central process of the first neuron of the dorsal column system ascends to:
the medulla oblongata
105
The first neuron of the spinothalamic system ascends in:
the dorsolateral fasciculus (just external to lamina 1)
106
In the spinothalamic system, the cell body of the second neuron may lie in:
lamina 1, 2, 3 or 4
107
The axon of the second spinothalamic neuron crosses the midline where?
in the anterior white commissure of the spinal cord
108
After crossing the midline, where does the second spinothalamic neuron ascend to?
the lateral spinothalamic pathway (pain and temperature sensation) or
the anterior spinothalamic tract (touch sensation)
109
what is the lateral spinothalamic pathway for?
pain and temperature sensation
110
what is the anterior spinothalamic tract for?
touch sensation
111
Dorsal column (gracile and cuneate fasciculi) carry what information?
touch,
deep pressure,
proprioceptive
vibration sense
112
the gracile fasciculus mainly conveys information from where?
the hindlimb
113
the cuneate fasciculus mainly conveys information from where?
the forelimb
114
Where do the cuneate and gracile fasciculi cross the midline?
in the brainstem
115
The dorsal spinocerebellar and ventral spinocerebellar tracts convey what information
position sense (proprioception)
tactile
116
The dorsal spinocerebellar and ventral spinocerebellar tracts convey information to where?
the cerebellum
117
What side do The dorsal spinocerebellar and ventral spinocerebellar tracts end?
the same side that they began
118
the first neuron of the dorsal spinocerebellar and ventral spinocerebellar systems is a:
dorsal root ganglion cell
119
What is anothe name for the dorsal nucleus?
the nucleus of Clarke
120
the first neuron of the dorsal spinocerebellar and ventral spinocerebellar systems ends by synapsing on neurons of the:
dorsal nucleus (nucleus of Clarke)
120
what is the dorsal nucleus (nucleus of Clarke)?
a prominent cell group found in thoracic and upper lumbar levels
(same levels at which the preganglionic column of the sympathetic nervous system is located)
121
The dorsal nucleus lies in what direction in relation to the central canal?
just dorsolateral
122
The axons of dorsal nucleus cells form the:
dorsal spinocerebellar tract
123
The axons of dorsal nucleus cells form the dorsal spinocerebellar tract where?
in the lateral funiculus
124
What is another name for the dorsal nucleus?
the nucleus of Clarke
125
the dorsal spinocerebellar tract ends where?
the cerebellar cortex of the same side.
126
The ventral spinocerebellar system ends where?
the cerebellar cortex of the same side.
127
Both the dorsal spinocerebellar and ventral spinocerebellar systems serve only:
the body's rear half
128
what tract is the body's front half served by
the external cuneate system
