NS 5 - ascending tract Flashcards
how many pairs of spinal nerves are there?
31
is the spinal cord shorter than the spinal canal?
yes
what type of neurons project their axons into the periphery to innervate skeletal and smooth muscles that mediate voluntary and involuntary reflex?
motor neurones
where are motor neurons located?
ventral horn
what can cause motor and sensory abnormalities?
lesions in different parts of the spinal cord
what defines a spinal segment?
dorsal roots entering and ventral roots exiting the cord
define dermatome
an area of skin supplied by peripheral nerve fibres originating from dorsal root ganglion
can there be overlap between neighboring dermatomes?
yes
how are peripheral nerves formed?
ventral axon root joins with peripheral processes of the dorsal root ganglion cells to form mixed afferent and efferent spinal nerves
describe what the transverse section of the adult spinal cord looks like?
white matter in the periphery, gray matter inside and a tiny central canal filled with CSF at its centre
what surrounds the canal in a transverse section of the adult spinal cord?
the ependymal layer
what type of nuclei is present in the dorsal horn?
sensory
what are the three main categories of neurons found in spinal gray matter?
motor cells of ventral horn
tract cells and interneurons
does white matter increase or decrease going up the tract?
increase
name the three columns present in white matter
dorsal columns - sensory
lateral column - mixed
ventral column - mixed
what can be sampled by inserting a needle into the subarachnoid space below the level of the conus medullaris?
CSF
how many arteries supply the cord?
three major longitudinal arteries
- one anterior and two posterior that originate from vertebral arteries
- radicular arteries that travel along the dorsal and ventral roots
what causes a spinal cord infarction
embolic occlusion
what happens at the white commissure?
crossing of neurons
where would you puncture the needle for a spinal tap?
L4/5
which senses are provided by the dorsal column pathway?
- two point discrimination/ fine touch, vibration and conscious position sense
