spinal cord and spinal nerves Flashcards
describe arachnoid mater
- thinner more delicate than dura
- continuous w/ arachnoid
- ends at S2
what is the main function of denticulate ligament
anchor spinal cord to dura
structure and function of filum terminale
- only pia mater no neurons
- anchor spinal cord to coccyx
where is the epidural space and what does it contain
- btwn bones forming vertebral canal and dura mater
- contains: fat, vertebral plexus of veins
where is the subarachnoid space and what does it contain
- btwn pia and arachnoid mater
- ends at S2
- contains: CSF
what is the function of the motor neuron
- info sent from spinal cord to muscle
- efferent pathway
what are the components of the motor neuron
- cell body: found in ventral grey matter of spinal cord
- one axon connected to cell body
- upper and lower neurons
upper vs lower neurons of motor neurons
- upper: before it exits the spinal cord
- lower: leaving the spinal cord to go to muscles
what is the function of a sensory neuron
- info sent from peripheral receptor to spinal cord
- afferent pathway
components of sensory neuron
- cell body found in dorsal root ganglia
- one axon that splits into peripheral and central processes
peripheral vs central processes of the sensory neuron’s axon
- peripheral: goes to skin to get signals then back to cell body
- central: leaves the cell body and goes to spinal cord
where does the spinal cord start and end
- continuation of medulla oblongata of brain stem
- ends at conus medullaris @ L1/L2
what and where are the spinal cord enlargements
- lots of neurons to innervate upper and lower limbs
- cervical: C4-T1
- lumbosacral: L4-S3
what does grey matter contain?
- unmyelinated axons
- cell bodies of interneurons
- cell bodies of motor neurons in ventral horn
what does white matter contain
- myelinated axons
- sensory neurons carrying info to spinal cord
- connecting neurons whose axons relay info to brain
- motor neurons whose axons convey info from brain to spinal cord
where are segmetns located in the cervical region of the spinal cord
- next to corresponding vertebrae
- take almost vertical path before leaving spinal cord
where are segments located T1-Cox
- segments originate superior to corresponding vertebrae
- dont exit intervertebral foramen until below corresping vertebrae
what kind of neurons to spinal nerves contain
sensory (dorsal ROOTS) and motor (ventral ROOTS)
what happens when the spinal nerve exits the intervertebral foramen?
-splits into dorsal and ventral ramus
what are somatic nerve plexi
ventral rami from specific segemtns of spinal coredthat innervates skin and musles of specific region of body
what and where are the 4 somatic nerve plexi
- cervical: C1-4
- brachial: C5-T1
- lumbar: L1-4
- sacral: L4-S4
where do the 4 somatic nerve plexi innervate
- cervical: anterior and lateral back
- brachial: upper limb
- lumbar: anterior and medial thigh and lower ab wall
- sacral: poasterior thight, gluteal region, perineum, leg and foot
what happens when there is a complete lesion to a nerve
paralysis of muscles supplied by damaged nerve if there are no other nerves innervating those muscles
what happens when there is a branch lesion to a nerve
paralysis of the muscles supplied by that branch along w/ loss of senssation
what happens when there is a lesion to a spinal nerve
- muscles weakness
- partial loss of sensation
what happens where there is a lesion to the spinal cord
widespread bilateral loss of sensation and muscle paralysis below site of injury
