Physiology 7: Spinal Reflexes, UMNs and Control of Movement Flashcards
name the motor spinal tracts that run down the LATERAL pathway
corticospinal (main)
rubrospinal
name the motor spinal tracts that run down the VENTROMEDIAL pathway
vestibulospinal
tectospinal
reticulospinal (medial and lateral)
spinal tracts that take the lateral pathway are under control of what part of the brain?
cerebral cortex
lateral pathways mainly control..
voluntary control of distal muscles
ventromedial pathways mainly control…
posture and locomotion
spinal tracts that take the ventromedial pathway are under control of what part of the brain?
brainstem
cell bodies of the corticospinal tract are located in..
motor cortex (most) somatosensory areas of the parietal cortex
where does the corticospinal tract’s pyramids form?
medulla
why does the corticospinal tract divide into lateral and ventral?
most fibres split at the pyramidal decussation and go more laterally, the ones that dont stay more central
where are the rubrospinal tract’s cell bodies located?
red nucleus in the midbrain
decussation point of the rubrospinal tract?
ventral tegmental decussation
where is the rubrospinal tract in relation to the corticospinal tract?
anterolateral
what does the rubrospinal tract do?
excites LMNs of limb flexors
a lesion in the lateral pathways could cause what? what would it NOT affect?
loss of single movements of body parts
slow, impaired voluntary movements
POSTURE IS FINE
cell bodies of the vestibulospinal tract are located where?
lateral and medial vestibular nuclei
where specifically do the axons from the lateral and medial vesibular nuclei go? where do they terminate?
lateral- descend ipsilaterally in the lateral VS tract to the LUMBAR spinal cord
medial- descend in the medial VS tract as far to the CERVICAL spinal cord
cell bodies of the tectospinal tract reside where?
superior colliculus
the superior colliculus recieves input from…
visual cortex and retina
where do the tectospinal tract’s axons decussate?
DORSAL tegmental (not segmental) decussation
the tectospinal tract is very medial T or F
T
where does the tectospinal tract terminate and why?
cervical spinal cord as it is there to supply neck and shoulder muscles for the body to respond to visual stimuli eg moving head
which reticulospinal tract is for contraction of lower limbs
medial
which reticulospinal tract is for reflex control
lateral
the medial RS tract descends __laterally and the lateral RS tract descends __laterally
ipsi
bi
name 4 ways that spinal interneurons receive innervation
via: sensory afferents eg 1a/1b descending axons from brain LMN branches other interneurons
these nerve cells can be excitatory or inhibitory and have a role in coordinating control of flexion and extension…
spinal interneurons
the myotatic reflex depends on what other than the extensor muscle itself?
the extensor’s antagonist flexor muscle MUST be relaxed! eg quadriceps antagonist is the hamstrings
contraction of a muscle during a reflex is caused by what nerves?
innervation from excitatory interneurons
inhibition of a muscle during a reflex is caused by what nerves?
inhibitory interneurons
