chapter 13 Flashcards
the spinal cord has a
and it is surrounded by
and includes these nuclei
narrow central canal; gray matter; dorsal sensory and ventral motor nuclei
gray matter
dominated by unmyelinated neuron/neuroglia cell bodies
white matter
contain myelinated and unmyelinated axons that ascend and descend
nuclei
bundles of grey matter in the CNS
tract
bundles of axons in the CNS
somewhat uniform in diameter, myelination and propagation speed
short tract
send sensory and motor signals to spinal cord segments
long tracts
connect the spinal cord with the brain
ascending tract
send sensory information to the brain
descending tract
bring motor commands to the spinal cord
each nerve segment is connected to a pair of
spinal nerves
spinal nerves are wrapped in
endoneurium, perineurium and epineurium
fiber
a single axon with an endoneurium
fascicle
a bundle of fibers within a perineurium
nerve
a bundle of fascicles within an epineurium
the functions of the spinal cord are
- to process reflexes
- to integrate EPSPS and IPSPS
- to conduct sensory impulses to the brain and motor impulses to effectors
where are relay neurons found
in the brain and spinal cord
what are spinal reflexes
rapid, automatic reponses that trigger specific stimuli and are controlled by the spinal cord alone
what are the exact measurements of the spinal cord?
18 inches long and 1/2 inch wide
it ends between L1 and L2
what is the central canal full of ?
CSF
what causes spinal cord enlargement?
amount of grey matter in the segment
involves nerves of limbs
cervical enlargement
nerves of shoulders and upper limbs
lumbar enlargement
nerves of pelvis and lower limbs
conus medullaris
a thin spinal cord below the lumbar enlargement
filum terminale
a thin thread of fibrous tissue at the end of the conus medullaris and is attached to the coccygeal ligament
cauda equina
nerve roots that extend below the conus medullaris
cervical nerves are named for ____ while all other nerves are named for _____
inferior vertebra, superior vertebra
what are dorsal roots?
they contain axons of sensory neurons and bring sensory information to the spinal cord
what are ventral roots?
they containa axons of motor neurons and control somatic and visceral effectors
what is dorsal root ganglia?
transmit sensory info from PNS to CNS and contains cell bodies of sensory neurons
what binds together to form a spinal nerve?
sensory and motor roots, which will then form branches of nerve fibers
spinal nerves are ____ nerves which carry these kind of fibers
mixed nerves that carry both afferent and effferent fibers
the spinal cord is protected by the
vertebrae, spinal meninges and CSF
what is the function of the spinal meninges?
to circulate nutrients, blood and absorb shock
spinal meninges
dura mater
list characteristics
- tough outer layer
- fibrous, fused with occipital bone
- tapers to join the filum terminale in coccygeal ligament
- connected to the cranial dura mater
arachnoid mater
composed of an arachnoid membrane made of simple squamous epithelium
contains collagen and elastin fibers that are filled with CSF
pia mater
thin, weblike, bound to neural tissue
paired with denticulate ligaments
epidural space contains
areolar tissue, blood vessels and adipose tissue
between ventral wall canals and spinal dura mater
subarachnoid space contains
CSF, arachnoid trabeculae
the posterior gray horns contain
somatic and visceral sensory nuclei
the anterior gray horns contain
somatic motor nuclei
the lateral gray horns contain
visceral motor nuclei and are found in thoracic and lumbar segments
what is the gray commisure
axons that connect one side of the SC to the other
tracts or fasciculi
found in the white columns
made of bundles of axons
relay information all the in same direction
ascending tracts carry information to the
brain
descending tracts carry information to the
spinal cord
peripheral neuropathies are when
there are regional losses of sensory and motor functions due to nerve compression
ipsilateral
same side of the body
(stretch, tendon reflex)
contralateral
opposite sides of the body
monosynaptic
two neurons, one synpase
polysynaptic
multiple synapses