lecture 3 - spinal cord Flashcards
(89 cards)
1
Q
spinal cord functions (3)
A
conducts sensory impulses to the brain and motor impulses to effectors
integrates EPSPs and IPSPs
processes spinal cord reflexes
2
Q
white matter consists of:
A
sensory and motor tracts
3
Q
tracts
A
bundles of axons in the CNS
4
Q
site for integration
A
grey matter
5
Q
spinal cord reflexes only involve:
A
spinal nerves and spinal cord
6
Q
spinal cord is protected by (3)
A
vertebral column
meninges
CSF
7
Q
vertebral canal is formed by
A
vertebral foramen in a line
8
Q
intervertebral foramen vs vertebral foramen
A
vert - spinal cord passage
inter - spinal nerve passage
9
Q
meninges (3) deep to superficial
A
pia mater
arachnoid mater
dura mater
10
Q
all laters of spinal cord stuff deep to superficial (7)
A
spinal cord
pia mater
subarachnoid space
arachnoid mater
subdural space
dura mater
epidural space
11
Q
epidural space
A
contains fat
outermost layer
12
Q
dura mater
A
toughest
continuous with epineurium
13
Q
subdural space
A
filled with ISF
14
Q
arachnoid mater
A
spider like
thin
avascular coverings of collagen + elastic
continuous to brain
15
Q
subarachnoid space
A
filled with CSF
16
Q
pia mater
A
delicate
highly vascularized
adheres to spinal cord and brain
has denticulate ligaments
17
Q
denticulate ligaments
A
part of pia mater that hold the spinal cord in place
18
Q
cerebrospinal fluid (what does it do?)
A
CSF
circulates through the brain ventricles and subarachnoid space
19
Q
how is CSF removed?
A
removed from the subarachnoid space via a spinal tab or lumbar puncture between L3/L4 or L4/L5
20
Q
spinal cord extends to and from:
A
medulla oblongata to L2 in adults
21
Q
spinal enlargements
A
cervical - arms
lumbosacral - legs
these are present to innervate the limbs
22
Q
hoe many pairs of spinal nerves
A
31
23
Q
cervical nerves (which ones)
A
first 8
24
Q
cervical enlargement nerves
A
C4 - T1
25
thoracic nerves
T1-12
26
lumbosacral enlargement nerves
T9-12
27
lumbar nerves
L1-5
28
sacral nerves
s1-s5
29
coccygeal nerve
last pair of nerves
30
conus medullaris
terminal end of the spinal cord at L1/l2
cone shaped
31
cauda equina (horses tail)
roots of lowest spinal nerves
resembles a horses tail
32
filum terminale
extension of pia mater
anchors spinal cord to coccyx
33
white matter functions as
highways for upward and downward travel of information
34
grey matter functions to
integration nerve impulses
35
grey matter of the spinal cord
shaped like an H
has paired horns
- posterior grey horns
- anterior grey horns
- lateral grey horns
has central canal
36
central canal
runs whole spinal cord
filled with CSF
37
posterior grey horns have:
axons of sensory neurons
cell bodies, and axons of interneurons
38
anterior grey horns have
somatic motor nuclei to skeletal muscle
39
lateral grey horns have
autonomic motor nuclei
40
if there was a loss of function at the lateral grey horns of the spinal cord, what would happen?
there would be a loss of autonomic motor function (cardiac muscle, smooth muscle, glands)
41
white matter of the spinal cord
surrounds grey matter
has grooves that divide it in half
divided into funiculi by grey horns
- anterior posterior and lateral funiculi
42
funiculi (and what they contain?)
sections of white matter in the spinal cord that contain tracts
43
a tract contains
axons with common origin/destination
44
ascending tracts vs descending
asc - carry info up to brain - sensory
desc - carry info down from brain - motor
45
tracts are names based on:
location, beginning to end
eg. spinothalamic tract
starts in spinal cord, ends in thalamus
46
motor tracts can be divided into 2 types
direct (pyramidal)
indirect (extrapyramidal)
47
spinal ganglion
bulges of sensory cell bodies shortly before entering the spinal cord
48
rootletts
small nerves that enter/exit the cord, become/were roots
rootletts -> roots > nerves
49
anterior medial fissure
anterior groove in spinal cord
50
posterior medial sulcus
posterior groove in spinal cord
51
why is the amount of grey matter largest in cervical and lumbar segments?
the enlargements are there
52
how does the white matter content change in the spinal cord from superior to inferior? why?
it gets less and less as we go down
this is because as tracts exit the spinal cord, there is less info coming from the brain by the bottom
53
the internal anatomy of the cord allows sensory and motor info to be:
processed in an organized way
54
nerve
bundles of hundreds/thousands of axons outside of the brain/cord
made of neurons
bundle of fascicles within an epineurium
55
layers of nerves
endoneurium
perineurium
epineurium
just like muscle
56
fiber
single axon within an endoneurium
57
fascicle
bundle of fibres within a perineurium
58
all layers of nerve deep > superficial
(6)
single axon
endoneurium
bundle of fibres
perineurium
bundle of fascicles
epineurium
59
spinal nerves are connected to the cord by:
two roots (anterior and pos)
60
mixed nerve
a nerve that contains both sensory and motor axons
eg, when teh two roots meet from cord
61
posterior root
contains axons of sensory neurons
- conducts NPs from receptors toward CNS
- has spinal ganglion that contains cell bodies of the sensory neurons
62
anterior root
contains axons of motor neurons
- conducts nerve impulses from CNS to effectors
63
rami
branches of spinal nerves
64
types of rami and what they supply
posterior rami - deep muscles of posterior trunk
anterior rami - anterior trunk + limbs
meningeal branches - meninges, vertebrae
communicating rami - autonomic NS
65
anterior rami are special, why
the do not go directly to the part they supply, they go to axonal networks called plexuses
66
spinal plexus
webs of nerves that function to innervate all body parts extensively
67
5 spinal plexuses
cervical
brachial
lumbar
sacral
coccygeal
68
why is there no thoracic plexus
anterior rami directly innervate the intercostal spaces via the intercostal nerves
69
dermatomes
skin segments supplied by all the spinal nerves except C1
70
transection
injury that severs the spinal cord and leads to loss of sensation and motor control below the level of injury - higher = worse
71
reflex
fast predictable involuntary response to changes in the environment - can be inborn or learned
72
types of reflexes
spinal and cranial
somatic and autonomic
73
spinal reflex
integration takes place in spinal cord
(in the grey matter)
74
cranial reflex
integration takes place in brain
75
somatic reflex
involves contraction of skeletal muscles
is perceived
76
autonomic reflex
involves contraction of smooth muscle, cardiac muscle, or glands
is not perceived
77
reflex arc (what is it + 5 things involved)
the pathway followed by nerve impulses in a reflex
1. sensory receptor
2. sensory neuron
3. integrating centre
4. motor neuron
5. effector
78
monosynaptic reflex arc
arc that involves one synapse
ex. hammer knee reflex
79
polysynaptic reflex
arc that involves more than one synapse
ex. stepping on a sharp object
80
whihc neurons participate in a monosynaptic reflex
just sensory and motor
81
4 important somatic spinal reflexes
stretch
tendon
flexor
crossed extensor
82
stretch reflex
monosynaptic
ipsilateral
(with polysynaptic arc to antagonist muscles)
operates as a feedback mechanism to control muscle length by causing muscle contraction
ex. patellar reflex
83
reciprocal innervation
simultaneous contraction of one muscel and relaxation of its antagonist
84
tendon reflex
polysynaptic
ipsilateral
(with polysynaptic arc to antagonist muscles)
operated as a feedback mechanism to control muscle tension by causing relaxation when muscle force is too extreme
ex. when quads tense up too much they are signalled to relax + and hammies to contract)
85
flexor reflex
polysynaptic
ipsilateral
intersegmental
protective reflex that moves a limb in response to pain.
intersegmental - activation of interneurons that branch to dif cord segements - engages several motor fibre segments
multiple muscle groups activated to move limb
86
crossed extensor reflex
polysynaptic
contralateral
helps to maintain balance during the flexor reflex
interneurons that synapse to motor neruons on contralateral side activate opposing side muscles
used to balance on one leg if the other is injured
87
babinski sign
abnormal response to reflex test
88
direct motor pathways function to
(pyramidal)
cause voluntary movement of skeletal muscle
89
indirect motor pathways function to
(extrapyramidal)
cause automatic movements like muscle tone, postural muscles, and equilibrium of the body in response to head movement
