Spinal cord and periphery Flashcards
Are tracts made from grey or white matter?
white
What is the arrangement of grey and white matter in the spinal cord?
grey inside and white on the outside
Where are motor neuron cell bodies found in the spinal cord eg grey matter or white matter
ventral horn of grey matter
What is motor neuron disease?
group of diseases affecting the neuron in the ventral horn of spinal cord - lower motor neuron
How does motor neuron progress?
nerve dies and so the muscle supplied by this nerve atrophies and have no reflexes or tone
degenerative and incurable
What are the 2 broad types of white matter pathways?
ascending - sensory and descending - motor
What are the 3 columns of tracts called?
lateral, anterior and posterior
What do the corticospinal/pyramidal tracts control?
motor function = control of voluntary skilled movements
Where do corticospinal tracts cross?
decussation of pyramids - medulla
Are corticospinal tracts classes as UMN or LMN?
upper
How many neurons are in ascending pathways?
3
What neuron ALWAYS crosses over in ascending pathways?
2
What are posterior/dorsal columns responsible for?
fine touch, proprioception, vibration sense
Where do posterior columns cross over?
2nd neuron crosses at the medulla - upper portion
Where does the 2nd order neuron end and hence the 3rd order neuron start in dorsal pathways?
thalamus
In dorsal pathways what part of the brain does the 3rd order neuron travel to?
parietal lobe - post central gyrus
What are spinothalamic tracts used for?
pain and temperature
What level do spinothalamic tracts cross over?
the level they enter the spinal cord
Lesion above level of crossing…
defecit on opposite side
lesion below level of crossing…
defecit on same side
Where do motor tracts originate?
cerebral cortex and brainstem
Motor/descenidn gpathway function
control of movement, muscle tone and spinal autonomic functions
Tracts coming from cerebral cortex have how many neurons in their pathway?
2
Where do motor tracts decussate?
medulla - pyramidal decussation
What are the 2 neurons in the motor pathway referred to as?
UMN and LMN
Is the UMN or LMN responsible for reflexes and tone?
LMN
If there is damage of the UMN what would happen?
tone increased and reflexes exaggerated
What are reflexes?
involuntary stereotyped pattern of response brought about by a sensory stimulus
What are reflexes mediated at spinal cord level known as?
spinal reflexes
Is the stretch or flexor reflex monosynaptic?
stretch
How is the stretch reflex protective?
polysynaptic arc to inhibitory neuron for reciprocal innervation eg knee bucking
What does the flexor reflex help protect the body from?
painful stimuli
spastic paralysis and hyperflexia - UMN or LMN lesion?
UMN
List some things you would enquire about if there is a neurological lesion
cortical problem eg speech
motor paralysis/weakness - what side, spastic/flaccid, reflexes
sensory defect - what side? for pain+temperature and then proprioception, vibration etc
cranial nerve weakness - what side?
How many neurons are there in the autonomic nervous system?
2
ANS function?
innervation and control of secretory glands, smooth muscles and organs
Sympathetic outflow
thoracolumbar
Parasympathetic outflow
craniosacral
Does parasympathetic or sympathetic have ganglia near the target organ?
parasympathetic
Does parasympathetic or sympathetic target every body cell?
sympathetic
