Ch. 15 Flashcards
CNS communicates tracts
ascending or descending
ascending tracts go
inferior to superior/ brain
descending tracts carry info
brain to spinal cord or superior to inferior
sensory ascending tracts involve neurons #
3
first order neuron sensory ascending tracts
convey info about stimulus to environments
first order neuron enter through
dorsal root of spinal cord
cell body first order neuron is
clustered with others
first order synapses on cell body to be
second order neuron
second order neuron specialty
crosses over to opposite side of body aka deccesation
second order neuron goes into brain to synapses again to be
third order neuron
left foot will be processed
right side brain
sensory modality arrangment
pain are with pain, fine touch with fine touch
somatotopic arrangement
fine touch neurons lower limb are in certain tract, upper limb different tract
medial lateral rule
inferior are arranged medially while neurons are superior will be more laterally
posterior columns located
posterior columns in white matter
posterior columns convey
limb position, fine touch, pressure, vibration
posterior column 1st neuron
starts at receptor then conveys info into posterior column into medulla oblongata to then synapse
posterior column 2nd neuron
medulla oblongata decussate and ascend to thalamus
posterior column 3rd neuron
convey info to primary somatosensory cortex
anterior spinothalamic tract carries
info about crude touch and pressure
anterior spinothalamic tract first order neurons
receptor pass up to spinal cord and terminates
anterior spinothalamic tract second order neurons
located in dorsal horn gray mater, decussate to other side and ascend to thalamus
anterior spinothalamic tract 3rd order
synapse again and goes to primary somatosensory cortex
lateral spinothalamic tracts located
lateral white column spinal cord
lateral spinothalamic tracts carry info on
pain and temp
lateral spinothalamic tracts 1st order
start at receptor up to spinal cord and synapse at entry
lateral spinothalamic tracts 2nd order
decussate and ascend to thalamus
lateral spinothalamic tracts third order
start thalamus and go to primary somatosensory cortex
spinocerebellar tracts carry info about
proprioception (unaware)
spinocerebellar tracts first order
receptor to spinal cord to stop
second order neurons first type
decussate immediately to the brain to decussate again to end in same place
second order neuron second type
doesn’t decussate up to cerebellum
motor descending tracts conduct
efferent impulses from brain to spinal cord
how many motor neurons in a pathway
at least 2
spinal cord main tracts
anterior and lateral corticospinal tract
upper motor neurons originate in
primary motor cortex
% of axons decussate in pyramids and enter lateral corticospinal tract on contralateral side
85
% of axons enter anterior corticospinal tract on ipsilateral side and decussate at targeted segment
15
subconscious motor pathways help control
neck, trunk, and limbs
ALS means
amyotrophic lateral sclerosis
ALS is progressing
rapidly
ALS affects control of
motor
ALS more common in
males
symptoms of ALS after age
40
