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27 Cards in this Set
- Front
- Back
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how many spinal arteries are on each side of the spinal cord?
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- anterior surface has single ventral artery
- posterior surface has two dorsal arteries |
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what level does the spinal cord end at?
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- L1/2
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what happens to the length of the spinal nerves as you go further down the spinal cord?
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- length of roots from cervical to sacral become longer
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what are the cervical & lumbar enlargements?
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- cervical enlargement is for upper extremity
- lumbar enlargement is for lower extremity |
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how does reciprocal inhibition of stretch reflex work?
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- inhibit the antagonist muscles while the agonist muscles fire
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what is the flexor reflex?
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- when you step on a nail
- A nociceptive fiber from the foot enters the spinal cord and activates motor neurons to iliopsoas and hamstring muscles to contract them to move away |
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what is the crossed extension reflex?
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- after stepping on a nail there is strong activation of the contralateral muscles
- helps the leg with the nonpunctured foot to support the body |
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what is lissauer's tract?
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- information about pain and temperature from the spinothalamic pathway heads up a few segments before it synapses
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what is the substantia gelatinosa?
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- where fibers from pain from spinothalamic pathway enter
- poorly myelinated, present at all spinal levels |
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which tract has poorly myelinated fibers? which has heavy myelinated?
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- spinothalamic pathway
- dorsal column pathway |
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what cell bodies live in the intermediolateral cell column?
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- site where sympathetic nervous system preganglionic neurons are located
- from T1-L2 |
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what is dorsal nucleus of clarke?
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- nucleus that transmits information to the cerebellum
- present from T1-L2 |
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what levels do preganglionic parasympathetic fibers come from?
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- S2-4
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what is somatotopic organization?
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- where fibers are arranged systematically depending on which part of the body is served
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where does is the 3rd order neuron cell body located?
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- located in the thalamus and then relay information up to the somatosensory cortex
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what does the posterior (dorsal) column pathway transmit information from?
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- position sense, vibration sense, 2 pt discrimination
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what levels does the fasiculus gracilis start? where do the neurons go to? is it more medial or lateral?
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- T6 and below - lower limb
- go up to the 2nd order neurons in the caudal medulla - more medial |
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what level does the fasiculus cuneatus start? where do the neurons go to? is it more medial or lateral?
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- T5 and above - upper limb
- go up to the 2nd order neurons in the caudal medulla - more lateral |
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where do the second order neurons of the posterior dorsal column pathway cross over?
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- they cross over via 2nd neurons in the caudal medulla & send it up to the thalamus on the opposite side
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what divides the fasiculus gracilis & cuneatus?
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- a sulcus
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when do you get a positive romberg sign?
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- person has problem knowing position of legs in space so you have a lesion or demyelination in the fasiculus gracilis
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what is the difference in the location of the 2nd order neuron for the dorsal column pathway and spinothalamic pathway?
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- dorsal column 2nd order neuron is in the caudal medulla
- spinothalamic pathway is crossing over on the level or a few levels away via the ventral white commissure |
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if you have a lesion on the left spinothalamic tract where would the lesion present?
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- on the right
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if you have a lesion on the left dorsal column where would the lesion present?
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- on the left
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what is suspended sensory loss?
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- lesions do not involve long tracts
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what happens if you cut the ventral white commissure?
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- end up with suspended sensory loss bilaterally
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what happens if you cut the dorsal root?
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- you lose somatosensory coming in from that side
- and pain & temp on the same side (because it is before it crosses) |
