Unit 4 Flashcards
(177 cards)
1
Q
how long is the spinal cord?
A
40-45cm long
16-18 inches
2
Q
what is the maximum diameter and where?
A
1.3 cm maximum diameter in the cervical enlargement
3
Q
where is the narrowest vertebral canal?
A
C5-C6 the cord occupies 75% of the vertebral canal
4
Q
what is the weight of the spinal cord?
A
27 to 35 grams (approx 1oz)
only 2% of the total CNS weight
5
Q
what is the convenient superior boundary of the spinal cord?
A
Foramen Magnum- line of demarcation
6
Q
what is the precise superior boundary of the spinal cord?
A
the superior most ventral rootlet of the first cervical spinal nerve
7
Q
what is the adult Inferior Boundary?
Conus Medullaris
A
the disc between vertebral levels L1-2
this leaves about 1/3 of the vertebral and sacral canal below
8
Q
how many spinal nerve pairs are there?
A
31 pairs
9
Q
each nerve will have what type of rootlets?
A
dorsal and ventral roots
10
Q
what is the law that states that dorsal roots contain sensory (afferent) fibers and Ventral roots are motor (efferent) fibers?
A
the Bell-Magendi law
we now know a few afferent fibers come through the ventral root but the general idea is valid
11
Q
Roots (rootlets), spinal nerves and their Rami are what type of structures?
A
PNS structures
12
Q
the only CNS structure in the vertebral canal is the?
A
spinal cord
13
Q
how are the Cranial nerves named?
A
they are named for the bone below
14
Q
which nerve exits between the occiput and atlas?
A
C1 its occasionally missing dorsal rootlets
15
Q
which spinal nerve exits at the intervertebral foramen between C3 and C4 vertebrae?
A
C4 spinal nerve
16
Q
Which spinal nerve exits at the intervertebral foramen between C7 and T1 vertebrae?
A
C8 spinal nerve
17
Q
how are the thoracic nerves named?
A
named for the bone above
18
Q
which nerve exits at the intervertebral foramen between T1 and T2 vertebrae?
A
T1 spinal nerve
19
Q
which nerve exits at the intervertebral foramen between T6 and T7 vertebrae?
A
T6 spinal nerve
20
Q
which spinal nerve exits at the intervertebral foramen of the T12 and L1 vertebrae?
A
T12 spinal nerve
21
Q
how are the lumbar nerves named?
A
named for the bone above
22
Q
where does L1 exit from the spinal column?
A
L1 exits at the intervertebral foramen between
23
Q
which nerve exits between L5 and S1 vertebrae?
A
L5
24
Q
which nerve exits from the Sacral Hiatus?
A
the Coccygeal nerve 1
Co1, this nerve might be missing
25
the cord of the vertebral column are approximately the same length during the first ______ months of embryonic development.
the first three months
26
During the rest of gestation the vertebral column lengthens _________ than the cord.
Faster
27
At birth the Co1 cord level is typically at the same level as the ________ vertebra?
L2-L3
28
By adulthood, the Co1 cord level is found at the ______ vertebral level in about 90% of people?
L1-L2
29
The tapering end of the cord is called the?
Conus Medullaris
30
the formation of the lumbar, sacral, and coocygeal roots that is below the cord and passes through the lumbar cistern is called?
Cauda Equina
31
the tiny and insignificant channel near the center of the spinal cord?
central canal
32
cranially, the central canal is continuous with what two structures?
medulla oblongata and the fourth ventricle
33
inferiorly the central canal expands into the conus medullaris as a?
terminal ventricle
34
terminal ventricle vs. Lumbar cistern
ventricle is a passage
| cistern is a resevoir
35
gray and white matter are found at what cord levels?
all cord levels
36
there are variations in relative amounts of gray and white matter through the cord levels. as you go down the cord there is less __________ matter.
less white matter
37
what horn is responsible for sensory afferent input which is heavy in nociceptors and thermoreceptors?
dorsal horn
38
which horn is primarily involved with activity in the sympathetic division of the autonomic motor system?
lateral horns
39
which horn control motor functions and is motor control for the axial muscles?
ventral horns
40
A ___________ is a longitudinal bundle of white matter fibers can be anatomically observed.
Funiculus
41
gray matter has a ________ concentration of neuron cell bodies.
dense
42
thick dendritic mats are located near the neuron cell bodies of which type of matter?
gray matter
43
which matter has dense capillary beds and support glial cells?
gray matter
44
groups of cell bodies form what?
Nuclei
45
how many rexed laminas are there?
10
46
there are many classification systems for cord nuclei based on what main 4 things?
shape
size
location of cell body
named after discoverer
47
which lamina is the thin cap over the posterior horn?
lamina 1
48
which lamina is responsible for pain and temperature sensations and gives rise to axons of the spinothalmic tract, also known as the posterior marginal nucleus?
lamina 1
49
which lamina appears gelatinous when examined in the fresh state?
lamina 2
50
which lamina has afferent fibers from lissauer's fasiculus and carries impulse important in transmission of pain, touch, and temperature. this also known as Substantia Gelatinosa?
lamina 2
51
the laminas that have much of their area filled with a group of cell bodies called the Nucleus Proprius?
lamina 3 and 4
52
which laminas receive touch and pressure stimuli, the dendrites of some of the neurons here extend into adjacent lamina
lamina 3 and 4
53
which laminae have axons of certain neurons located here cross to opposite side and contribute to the spinothalmic tract?
lamina 3 and 4
54
on the lateral edge of this lamina is a complex of fibers and cell bodies known as?
formatio reticularis
55
although lamina 5 is found at all cord levels, please remember that this ___________ __________ is only at the cervical area.
reticular formation
56
this lamina sends axons contralaterally to the lateral spinothalmic tract?
lamina 5
57
the ascending tract present through the entire cord and enters the cord at T6 and below, directly into the posterior funiculus?
Gracilis
58
the ascending tract that is located in the medial aspect of the posterior funiculus?
Gracilis
59
the ascending tract that is located in the lateral aspect of the posterior funiculus?
cuneatus
60
the ascending tract that enters the cord at level T6 and above, enters directly into the posterior funiculus?
cuneatus
61
the slender tract?
gracilis
62
the wedge shaped spinal tract?
cuneatus
63
the two spinal tracts located in the posterior columns?
gracilis
| cuneatus
64
the first neuron fibers of the gracilis terminate and synapse where?
nucleus gracilis of the medulla oblongata
65
the first neuron fibers of the cuneatus terminate and synapse where?
nucleus cuneatus in the medulla oblongata
66
the function of what tracts is to discriminate between two point touch and vibratory sensations?
gracilis
| cuneatus
67
what are the two major carriers for kinesthetic sensation (conscious proprioception)?
gracilis
| cuneatus
68
where do the gracilis and cuneatus fibers cross over?
internal arcuate fibers of the medulla oblongata
69
what would be a symptoms of a lesion of the posterior funiculus?
loss of proprioception
70
what is the cross over classification of the gracilis and cuneatus?
ipsilateral
71
the second neuron of the gracilis terminates and synapses where?
ventral posterior lateral nucleus of the thalmus
72
the second neuron fiber of the cuneatus terminates and synapses where?
ventral posterior lateral nucleus of the thalmus
73
the gracilis and cuneatus ascend from the medulla oblongata into the brainstem as the?
medial lemniscus
74
the third neurons of the gracilis and cuneatus terminate in the area of the brain that processes body sensations. what is this place?
post central gyrus
75
the tract located in all cord levels of the lateral funiculus?
lateral spinothalmic
76
the tract located in all cord levels of the anterior funiculus?
anterior spinothalmic
77
the tract responsible for pain and temperature sensation?
lateral spinothalmic
78
the tract responsible for light touch and pressure sensation?
anterior spinothalmic
79
the spinothalmic tract that crosses quickly upon entering the spinal cord?
lateral spinothalmic
80
which spinothalmic tract crosses gradually?
anterior spinothalmic
81
the first neuron of both spinothalmic tracts synapse and terminate where?
GRAY matter of the cord, right after entering cord
82
lesions of the spinothalmic tracts can lead to?
analgesia and thermoanaesthesia on the opposite side of the body
83
the second neuron fibers of the spinothalmic ascend to terminate and synapse where?
(VPL) ventral posterior lateral nuclei of the thalmus
84
when the spinothalmic tracts are considered together they make up what system
anterolateral system
85
the third neuron of the anterior spinothalmic tract terminates where?
post central gyrus
86
what funiculus is the lateral spinothalamic locate din?
lateral funiculus
87
what cord levels can the lateral spinothalamic be found?
all cord levels
88
what are the sensations of the lateral spinothalamic?
pain
and
temperature
89
when does the lateral spinothalamic tract cross in the spinal cord?
it crosses quickly
90
what funiculus is the anterior spinothalamic located in?
anterior funiculus
91
what cord levels can the anterior spinothalamic be found?
all cord levels
92
what sensations can be located with the anterior spinothalamic tract?
light touch
and
pressure
93
when does the anterior spinothalamic tract cross in the spinal cord?
crosses gradually
94
the lateral and anterior spinothalamic tracts are formed by axons that come from cell bodies in the?
gray horns of the cord
95
lesions in the spinothalamic tracts can lead to analgesia and thermoanaesthesia on which side of the body?
opposite side of the body
96
what does analgesia mean?
analgesia (loss of pain sensation)
97
what does thermoanaesthesia mean?
Thermoanaesthesia (loss of temperature sensation)
98
fibers of the spinothalamic tract ascend and terminate where?
thalamus (VPL nuclei)
99
when considered together, the spinothalamic tracts make up a large part of what system?
anterolateral system
100
the anterolateral system will also receive contributions from?
brainstem centers
101
what tract is located along the periphery of the lateral funiculus anterior to the post spinocerebellar tract?
anterior spinocerebellar tract
102
what tract have fibers that mostly cross in the cord, however most of these cross back again as they enter the cerebellum?
anterior spinocerebellar tract
103
which tract has fiber origins that are mostly in the lumbosacral cord's gray laminae?
anterior spinocerebellar tract
104
what tract has fibers that terminates in the cerebellum via the superior cerebellar peduncle?
anterior spinocerebellar tract
105
which tract sends input to the cerebellum on general state of gross movements of lower body and general activity of what is about to happen from motor neurons in that part of the cord?
anterior spinocerebellar tract
106
which tract is located along the periphery of the lateral funiculus, posterior to the anterior spinocerebellar tract?
posterior spinocerebellar tract
107
most fibers of which spinocerebellar tract do not cross?
posterior spinocerebellar tract
108
fiber origins from the posterior spinocerebellar tract are from cell bodies in what nucleus?
```
nucleus dorsalis (C8-L3)
tract not found below L3
```
109
fibers of the posterior spinocerebellar tract terminate in the?
cerebellum via the inferior cerebellar peduncle
110
what tract is responsible for proprioceptive input dealing mainly with fine movements from what has just happened in the muscle itself?
posterior spinocerebellar tract
111
proprioceptive fibers dealing with fine movements from the lower extremity may enter at cord levels below the?
nucleus dorsalis
112
proprioceptive fibers that enter the cord below the L3,2 level are carried into the nucleus dorsalis to synapse by what tract?
gracilis
113
fine proprioceptive fibers from the pectoral girdle and extremity synapse where?
accessory cuneate nucleus of the medulla oblongata
114
fibers entering at the cervical cord and ascend to synapse in the medulla oblongata's accessory cuneate nucleus, the fibers that leave here create the?
cuneocerebellar tract
115
the fibers of the cuneocerebellar tract ascend to the cerebellum through the?
inferior cerebellar peduncle
116
what are the ascending tracts not covered in class?
```
spinoreticular
spinocortical
spinoolivary
spinovestibular
spinopontine
spinotectal
```
117
what is the descending tract located in the anterior funiculus?
anterior corticospinal tracts
118
which corticospinal tract has about 5-15% of the total corticospinal fibers?
anterior corticospinal tract
119
most fibers cross in the spinal cord, after they come out of what tract?
anterior corticospinal tracts
120
what descending tract terminates as a tract by mid thoracic cord level?
anterior corticospinal tract
121
what is the tract with an unclear function but it seems to influence the axial musculature of the neck and shoulders?
anterior corticospinal tract
122
what tract is located in the lateral funiculus?
lateral corticospinal tract
123
which corticospinal tract contains the mass of the fibers 85-95%?
lateral corticospinal tract
124
most fibers of this tract cross in the pyramids of the medulla oblongata. what tract is this?
lateral corticospinal tract
125
which corticospinal tract runs the entire length of the cord?
lateral corticospinal tract
126
the tract whose function is critical for initiating and accomplishing precise skilled voluntary muscle movements. especially in the distal extremities?
lateral corticospinal tract
127
the left and right side of the corticospinal tracts each receive about a million fibers. 85-95% of these enter which corticospinal tract?
the lateral corticospinal tract
128
the majority of fibers entering the corticospinal tracts are small to moderate in diameter and lightly myelinated. what is the size range?
2-25 microns
129
the axons (fibers) of the corticospinal tracts are the only ones that begin in the __________ _________ and run uninterrupted to the spinal cord.
cerebral cortex
130
there is a decrease in fibers in each corticospinal tract as they descend the spinal cord. how many in each section % wise?
cervical 55%
thoracic 20%
lumbar 25%
131
many corticospinal fibers synapse with neurons in which lamina?
lamina 7
132
the corticospinal originating lamina 7 neurons usually find synapse with neurons in what other lamina, whose axons extend out to the PNS and innervate the musculature?
lamina 9
133
probably less than 3% of the lateral corticospinal axons terminate directly on which lamina?
lamina 9 neurons
134
most of the lateral corticospinal axons that do terminate on lamina 9 are the what cells from the precentral gyrus of the frontal lobe?
giant pyramidal (bertz)
135
what are the neurons that originate in the spinal cord or brain stem and extend fibers into the PNS to innervate somatic musculature?
lower motor neurons
136
what are the neurons from higher brain centers (cortex or brainstem) that influence the so-called lower motor neurons?
upper motor neurons
137
what is the name for a loss of function for the area of innervation?
lesion
138
```
reduction or absence of voluntary movement
hyperreflexia
increased muscle tone
clonus
babinski sign
these are symptoms of what?
```
upper motor neuron lesion
139
```
reduction or absence of voluntary movement
hypoflexia/areflexia
decreased muscle tone and atrophy
muscle fibrillations/ fasciculations
these are symptoms of what?
```
lower motor neuron lesion
140
what are the upper motor neurons that are involved with intiation of skilled voluntary movements?
pyramidal neurons
141
in the cord, the pyramidal fibers are known as?
corticospinal fibers
142
what are the complex of upper motor neurons, most of which originate in the brain stem and extend down the cord?
extrapyramidal neurons
143
what are the fibers that influence posture, muscle tone, enhance reflexes and thus allow voluntary movements to be smooth and effective?
extrapyramidal fibers
144
what is the origin of the tectspinal tract?
superior colliculus of midbrain's tectum
145
when do the fibers of the tectospinal tract cross?
as they descend
146
where do most fibers of the tectospinal tract terminate?
upper four cervical cord levels
147
what tract's function is; extrapyramidal reflex enhancement dealing with sight and auditory stimuli?
tectospinal
148
how does the tectospinal tract carry out its function?
accomplished by adjustments to trapezius and sternocleidomastoid muscles of the neck, moving the head.
149
what cranial nerve allows the tectospinal to carry out its function?
C.N 11 spinal accessory nerve
150
what is the origin of the rubrospinal tract?
nucleus ruber (red nucleus) of the midbrain's tegmentum
151
where do fibers of the rubrospinal tract cross?
fibers cross in the midbrain as they descend
152
though rubrospinal fibers may reach all levels, they predominately influence what?
hand and foot flexor musculature
| extensor musculature is simultaneously inhibited
153
the fibers of what tract are strongly influenced by the cerebellum and cerebral cortex for extrapyramidal muscle tone in contralateral hand and foot musculature?
rubrospinal tract
154
some investigations feel that these fibers may assume some of the fibers of what tract when it is damaged?
corticospinal tracts
155
what are the tracts associated with extrapyramidal fibers?
tectospinal
rubrospinal
vestibulospinal
156
what tract originates at the lateral part of the vestibular nucleus located in the medulla oblongata?
vestibulospinal
157
when do fibers of the vestibulospinal tract cross?
they do not cross
158
what is the tract that runs the entire cord length along the anterior-lateral funicular junction?
vestibulospinal
159
what tract is responsible for muscle tone and postural adjustment primarily in ipsilateral extensor musculature, while inhibiting flexors?
vestibulospinal
160
which tract maintains proper orientation in falling, and enhances spinal reflex capability?
vestibulospinal tract
161
the medial reticulospinal tract originates where?
pons tegmentum
162
the medial reticulospinal tract can be found in which funiculus?
anterior funiculus
163
where does the reticulospinal tract cross?
it is mostly uncrossed
164
what tract terminates at all cord levels in medial parts of ventral horn or intermediolateral cells?
medial (pontine) reticulospinal tract
165
what funiculus can the lateral reticulospinal tract be found in?
lateral funiculus
166
what is the origin of the lateral reticulospinal tract?
medulla oblongata
167
where does the lateral reticulospinal tract cross?
it is mostly uncrossed
168
what things are the reticulospinal tracts responsible for?
heart rate
blood pressure
respiratory rates and rhythms
169
where does the lateral reticulospinal tract terminate?
it terminates at all cord levels, in medial parts of the ventral horn or intermediolateral cells
170
when cell bodies originate in the cord and axons terminate in the cord it is known as?
spinospinal fibers
171
the fibers of which tract usually extend short distances up or down the cord, fibers may or may not cross?
fasiculus proprius
172
what is the tract that is located next to the gray horns and are subdivided into right and left lateral, anterior and posterior divisions?
fasiculus proprius
173
which tract is vastly important for coordination of spinal reflexes?
fasiculus proprius
174
what are the first first fibers to be myelinated in the fetus, and the earliest spontaneous movements are integrated here?
fasiculus proprius
175
what is the tract between the rexed lamina 1 and the posterior lateral sulcus of the cord?
dorsolateral tract
176
what is the tract primarily composed of small diameter collateral fibers off posterior root axons?
dorsolateral
177
the collateral fibers of the dorsolateral tract run short distances up or down the cord an dsynapse in the?
gray horns
| often in lamina 2
