Chapter 12 Flashcards
Length of Spinal Cord:
18 inches
Spinal cord ends between what vertebrae?
L1 and L2
How many cervical vertebrae?
8
How many thoracic vertebrae?
12
How many lumbar vertebrae?
5
How many sacral vertebrae?
5
How many coccygeal vertebrae?
1
C1 runs _______ 1st cervical vertebra
above
C8 runs _______7th cervical vertebrae
below
All others are named for vertebrae _______
above
Conus medullaris: cone shaped end of the spinal cord at _______
L1-L2
cone-shaped end of the spinal cord at L1-L2
conus medullaris
Thin thread of fibrous tissue at end of conus medullaris. Attaches to the coccygeal ligament
Filum terminale
Nerve roots that extend below conus medullaris
Cauda equina
Cauda equina is also called
“the horse tail”
superficial; myelinated & unmyelinated axons
white matter
deep; forms a H or butterfly shape. Mostly neuron cell bodies, neuroglia, unmyelinated axons.
gray matter
The central canal contains what?
cerebrospinal fluid
Shallow, longitude groove on posterior surface
posterior median sulcus
Deep groove on anterior surface
Anterior median fissure
What are the 2 branches if the spinal nerve roots?
- anterior (ventral) root
2. Posterior (dorsal) root
What root contains axons of motor neurons?
anterior (ventral) roots
What root contains axons of sensory neurons?
posterior (dorsal) roots
Dorsal root ganglia- contain cell bodies of _________ neurons
sensory
Each dorsal and ventral root join to form a ________ _______.
spinal nerve
Spinal nerves are MIXED meaning they carry both ______ and ________ fibers.
afferent (sensory)
efferent (motor)
afferent =
sensory
Functions of spinal meninges
- physical stability
- shock absorption
- carrying blood supply
A viral or bacterial infection of meninges
Meningitis
What are the 3 meningitis layers?
- Dura Matter
- Arachnoid matter
- Pia matter
the outermost layer of meningeal layers
dura matter
Cranially dura matter _______ with periosteum f occipital bone.
fuses
Dura matter:
tapers to dense cord of collagen fibers. Joins the film terminale in coccygeal ligament
Caudally
Dura matter:
between spinal dura matter and the walls of vertebral canal. Anesthetic injection site
Epidural Space
the middle layer of meningeal layers
Arachnoid matter
includes the arachnoid membrane: a layer of simple squamous epithelium that covers the arachnoid mater. . Subdural space, subarachnoid space.
Arachnoid matter
Arachnoid matter:
between arachnoid matter and dura matter
subdural space
Arachnoid matter:
between arachnoid matter and Pia matter.
subarachnoid space
the subarachnoid space is filled with
cerebrospinal fluid
the innermost layer of meningeal layers
Pia matter
anchored to underlying neural tissue. Paired denticulate ligaments
Pia matter
paired denticulate ligaments extend from ____ matter to __________ matter
Pia, arachnoid
What horn:
somatic and visceral sensory nuclei
posterior gray horn
What horn:
visceral motor nuclei
lateral gray horn
What horn is only found in thoracic and lumbar segments?
lateral gray horn
What horn:
somatic motor nuclei
anterior gray horn
Organization of gray matter:
- Gray horns
- Nuclei
- Gray commissures
Gray matter nuclei:
functional groups of neuron ______ _____ in gray matter of spinal cord
cell bodies
Gray matter nuclei:
receive and relay sensory information
sensory nuclei
Gray matter nuclei:
issue motor commands to effectors
motor nuclei
Gray matter:
contain axons that cross from side to side in spinal cord. Located posterior and anterior to the central canal
gray commissures
Organization of White Matter:
- Posterior white columns
- Lateral white columns
- anterior white columns
- tracts
between posterior gray horns and posterior median sulcus
posterior white columns
between anterior and posterior columns
lateral white columns
between anterior gray horns
anterior white columns
Tracts are found in the white columns containing bundles of ______ that relay information in the same direction
axons
what tract:
carry sensory information to the brain. in posterior columns
ascending tracts
what tract:
carry motor commands to the spinal cord. in anterior columns
descending tracts
each spinal cord segment is connected to a pair of spinal ______
nerves
what are the 3 connective tissue layers of spinal nerves?
- epineurium
- perineurium
- endometrium
what connective tissue layer:
outer layer. dense network of collagen fibers
epineurium
what connective tissue layer:
middle layer
perineurium
the perineurium divides nerve into _______(axon bundles)
fascicles
what connective tissue layer:
inner layer
endoneruium
the endoneurium surround the individual _______.
axons
Spinal nerve rami is both
motor and sensory nerves
poster ramus: innervates muscles, joints, skin of the _______
back
anterior ramus: innervates lateral and anterior _______; limbs
trunk
Rami communicates are in spinal nerves ____- _____.
T1-L2
rami communicates carry motor output of ________ division of the ANS
sympathetic
bilateral region of the skin, monitored by a specific pair of spinal nerves
dermatomes
dermatome boundaries can _________.
overlap
caused by the varicella- zoster virus
shingles
Shingles attacks neurons within the _________ of spinal nerves and sensory ganglia of cranial nerves
posterior root
Shingles come with painful rash that follows the path of the
dermatome of the affected nerve
A regional loss of sensory or motor function. Due to trauma or compression.
peripheral neuropathy
A complex interwoven “network” of nerve fibers.
nerve plexus
How do nerve plexus form?
they form from the blending of fibers of anterior rami of adjacent spinal nerves
4 major plexuses of ventral rami:
- Cervial
- Brachical
- Lumbar
- Sacral
Plexuses of ventral rami:
muscles of neck and diaphragm
Cervical
What major nerve runs through the cervical plexuses?
phrenic nerve
what nerve:
cervical plexuses
provides entire nerve supply to the diaphragm
phrenic nerve
Plexuses of ventral rami:
pectoral girdle and upper limb
brachial
Plexuses of ventral rami:
lower trunk, pelvic girdle, and lower limbs
lumbar and sacral
what nerve tuns through the sacral plexuses
sciatic nerve
what nerve:
sacral plexuses
largest/ longest nerve in the body
sciatic nerve
Neural reflexes preserve _________ through rapid adjustments
homeostasis
Neural reflexes are the basic building blocks of ______ ______.
neural function
one neural reflex= ____ motor response
one
Neural reflex steps: (5 steps)
- Stimulation of the receptor
- Activation of sensory neuron- enters spinal cord through posterior root
- information processing, signals sent to brain
- activation of motor neuron
- response of a peripheral; motor neurons release neurotransmitter at axon terminals
The stretch reflex has the least amount of _______ between sensory input and motor output
delay
In a stretch reflex the receptor is the
muscle spindle
A example of the stretch reflex
patellar reflex
Postural reflexes help maintain
posture
An example of postural reflex
standing
Withdrawl reflex moves body part away from
stimulus
an example of withdrawal reflex
flexor reflex; pulls hand away from hot stove
For a flexor reflex to work, we must have ________ _________.
reciprocal inhabitation
Ipsilateral- occur on the ________ of the body as stimulus
same
Contralateral- occult on the ________ of the body as stimulus
opposite side
Cross extensor reflex will affect the _____ leg in order to recieve body weight and maintain balance
other
reflex behaviors are autonomic but processing centers in the brain can _______ or _______ reflex motor patterns based in the spinal cord
facilitate or inhibit
Faciliation is called
reinforcement
stroking foot on lateral side of sole triggers extension of hallux and spreading of toes
Babinski reflex
The babinksi reflex is normal in who
infants
