Chapter 14- Spinal Cord and Spinal Nerves Flashcards
(44 cards)
1
Q
spinal cord: gross anatomy
A
-part of the CNS size and location: -slender nerve column -about 45cm long -starts at foramen magnum and ends between L1 and L2 (does not go into the sacrum) -31 pairs of spinal nerves
2
Q
overall structure
A
- bilateral symmetry
- consists of both gray and white matter
3
Q
central canal
A
hole down the center of cord; continuous with brain ventricles; both contain CSF
4
Q
2 grooves of spinal cord
A
anterior median fissure
posterior median sulcus
5
Q
enlargements
A
swollen regions of spinal chord
named based on region
-cervical enlargement
-lumbar enlargement
6
Q
conus medullaris
A
inferior most tip of spinal cord; cone shaped
7
Q
cauda equina
A
means horse’s tail; bundle of nerves inferior to spinal cord
8
Q
filum terminale
A
inferior most spinal nerve
9
Q
gray matter
A
- cell bodies, dendrites and synapses
- projections called horns
- cell bodies organized into nuclei
- -sensory
- -motor
10
Q
interior horns
A
posterior horn
anterior gray horn
lateral gray horn
11
Q
gray commissure
A
anterior commissure
posterior commissure
(separated by central canal)
12
Q
white matter
A
tracts and columns
- posterior white column
- ant. white column
- lateral white column
- ascending tract=sensory
- descending tract=motor
13
Q
meninges
A
membranes covering CNS
- are similar in both brain and spinal cord
- are split into layers called ‘mater’ (mother)
14
Q
superificial to meninges
A
vertebrae consists of vertebral arches -epidural space -space between meninges and vertebra -contains BV and adipose meninges connect to CT of spinal nerves
15
Q
spinal meninges: dura mater
A
tough mother
- durable
- deep to epidural space
- superficial to subdural space
- stabilized by coccygeal ligament
16
Q
spinal meninges: arachnoid mater
A
spidery mother
- superficial to suarachnoid space
- contains CSF
- CT looks like a spider web
17
Q
spinal meninges: pia mater
A
delicate mother
- light layer adhering to cord
- forms part of filum terminale
18
Q
spinal meninges order
A
vertebrae epidural space dura mater subdral space (with CSF) arachnoid layer subarachnoid space pia mater neural tissue
19
Q
spinal nerves
A
31 pairs
- 8 cervical (with 7 cervical vertebrae)
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
20
Q
nerve components
A
dorsal root -dorsal root ganglion -usually sensory ventral root -no ganglion usually motor
21
Q
nerve components (cont)
A
roots merge to form nerves
- hence spinal nerves usually are mixed (sensory and motor)
- all roots go through intervertebral foramen
22
Q
epineurium
A
surrounds the entire nerve
23
Q
perineurium
A
surrounds bundles of 10-100 axons (known as fascicles)
24
Q
endoneurium
A
surrounds each individual axon of each neuron
25
Rami
offshoots of a nerve once it exits the vertebrae
26
3 types of rami
dorsal ramus
ventral ramus
ramus communicantes
27
ramus communicantes
a splitting in the ramus separating sensory and motor fibers
white ramus communicantes
grey ramus communicantes
28
dermatomes
sensory innervation by specific spinal nerves
- spinal cord damage will result in loss of sensation in dermatome
- detection method
29
nerve plexus
```
braid off ventral rami
interconnected web of nerves for greater innervation
-found in several regions
-cervical
-lumbar
-sacral
(most thoracic nerves are all isolated
```
30
cervical plexus
C1-C4 and part of C5
| -innervate certain muscles of neck and torso
31
phrenic nerve
C3, 4 and 5
goes to diaphragm
results in breath
-part of cervical plexus
32
brachial plexus
C4-C8 and T1
| innervate the chest, upper back and arm
33
brachial plexus nerves
musculocutaneous
-to ant. muscles of arms and skin of forearm
ulnar nerve
-to muscles of forearm, hands and skin of hands
median nerve
-same as ulnar
-between radius and ulna
radial nerve
-to post. muscles of arms and skin of forearms and hands
34
lumbosacral plexus
last thoracic, lumbar, sacral and coccygeal nerves
| may be split into lumbar and sacral plexuses
35
lumbosacral plexus nerves
innervate the lower limb regions
obturator nerve
-to adductors of leg
-femoral nerve
-motor impulses to leg and thigh and receive sensory from skin of leg and thigh
sciatic nerve
-to muscles and skin in thighs, legs and feet
36
reflexes
- rapid automatic involuntary motor response to stimuli
- help preserve homeostasis
- occur at spinal cord or brain stem
- do not require cerebral processing
- can be modified by cerebral control
37
classification of reflexes
- by development
- site of processing
- nature of motor response
- complexity of neural circuit
38
classification by development
genetically: built in (innate)
learned: acquired through repetition and/or experience
39
classification by site of processing
spinal reflex: impulse only goes to spinal cord
| cranial reflex: makes it to the brain
40
classification by nature of motor response
somatic: influences the skeletal muscles system
-purely effector based skeletal muscle in this case
visceral (autonomic): influences the involuntary systems such as smooth muscle and glands
41
classification by complexity of neural circuit
how many synapses are involved
- monosynaptic=1
- polysnaptic=2 or more
42
steps of a reflex arc
1. receptor is stimulated by a detectible environmental stimulus
2. receptor stimulates a sensory neuron that sends a signal to the CNS for processing
3. information is processed by being transmitted to the appropriate neurons
-this could be a n interneuron or motor neuron
4-5. motor neuron is stimulated, sending a signal to an effector. this results in a behavior
43
stretch reflex
a reflex stimulated by the stretching of a muscle
- muscle spindle fibers are receptors that detect stretching
- effector is the contraction of the muscle
44
patellar reflex
patellar reflex is a stretch reflex
- functions to:
- prevent muscles form being overstretched
- prevent one from falling forward
