BLOCK 5 LECTURE 10 MOTOR Flashcards
what makes up the brain stem?
mid brain, pons, medulla oblongata
what is the channel through the mid brain called?
cerebrospinal aqueduct
what is behind the cerebroaqueduct?
tectum
where do the nerves in the midbrain originate from?
interpeducular fossa
what in on either side of the fossa?
peduncles
what are the two ridges on either side of the medulla called?
pyramids
what are the pyramids separated by?
medial sulcus
where are the nuclei for the first two cranial nerves?
for brain
where are the nuclei for cranial nerves 5-8?
pons
where are the nuclei for the cranial nerves 9-12?
medulla
what is the 4 pack on the dorsal suface of the midbrain?
colliculi
what is the only cranial nerve that comes out of the dorsal aspect of the CNS?
4th cranial nerve
what are the two neuron pathways in the descending tracts?
upper motor neurons and lower motor neurons
where do lower motor neurons have their cell body?
brain stem or spinal cord
where do lower motor neurons run to?
effector muscles
what happens in the reflex arc?
impulse enters the spinal cord via an interneuron and travels back via lower motor neurons
where do upper motor neurons originate?
cerebral cortex, cerebellum and brain stem
what are the structures of the internal capsule?
anterior limb, genu, posterior limb and retrolentiform area
with regards to the somatotropic arangement of the LMN, in dorsal columns what does a more medial fiber mean?
the more distal
how are the fibers running to the flexors and extensors arranged in the grey matter?
flexor fibers posterior
extensors are anterior
what is the ventromedial group of tracts for?
postural and girdle muscles
what are the dorsolateral tracts for?
distal muscles and fine movements
what are the ventromedial tracts?
pontine, tectal and vestibular
what are the dorsolateral tracts?
corticol, rubral and medullary
how does the pontine reticulo spinal tract run in the spinal cord?
ipsilaterally
where do the pontine reticulo spinal tracts synapse?
multiple segments of the spinal cord
what do the segments the pontine reticulo spinal tracts synapse with represent?
upper limb, trunk and lower limbs
what does the pontine reticulo spinal tract do?
mediates large movements
what is the other function of the pontine reticulo spinal tract?
they can also synapse onto the dorsal horn and modify sensory pulses - pulling hand away from the flame
where do the pontine reticulo spinal tract synapse to have an effect?
anterior horn cells
where does the tectospinal tract begin?
tectum
where do the collicular nuclei run to in the tectospinal tract?
cervical spinal cord - segements that supply the muscle of the neck and shoulders
what is the superior colliculi nuclei involved with in the tectospinal tract?
vision reflex
what is the inferior colliculi nuclei involved with in the tectospinal tract?
auditory reflex
where does the tectospinal tract decussate?
early
what are the tectospinal tract for?
orientating flinching movements
ballistic movements
navigational
where does the information come from for the vestibulospinal tract?
semi circle canals in the ears - uticle
how does the vestibulospinal tract run?
remains ipsilateral
where does the vestibulospinal tract run to?
all spinal segments
what does the vestibulospinal trac supply?
anti gravity muscles - extensor
what happens if you lose the ventromedial group?
you lose the ability to perform sudden changes in movement to correct posture
where does the rubrospinal tract decussate?
early
what does the rubrospinal tract run to?
muscles of the pectral girde
what is the rubrospinal tract used for?
control and co-cordination of movement
what do you get if you get a lesion of rubrospinal tract?
intention tremmor
impaired distal arm and hand movements
what is the journey of the corticospinal tracts?
cortex to the internal capsule in the brain stem to the spinal cord
in the corticospinal tracts how are the arm and face on the brain presented?
lateral
in the corticospinal tracts how are the legs on the brain presented?
medially
where do the corticospinal tracts pass through the internal capsule?
posterior limb
how does the corticospinal tracts pass through the brainstem?
through the cerebral peduncles, basilar pons and pyramids
where do most of the corticospinal tracts decusstae?
pyramids
what are the corticospinal tracts called that decussate in the pyramids?
controlateral lateral corticospinal tracts
what are the corticospinal tracts called that dont decussate in the pyramids?
anterior corticospinal tracts
where do the anterior corticospinal tracts decussate?
at the spinal level
what are the corticospinal tracts used for?
skilled voluntary motor movements
independant flexion of single distal movements
what is babinskis sign?
stroke the foot everything flexes, if babinskis is poastive toes go up
what happens in babinskis sign in children?
toes should go up
why is babinskis sign different in children?
the corticospinal tracts are unmyelinated in the first 2 years after birth
what happens when the hypothalaospinal tract pathway fails?
honors syndrome
in suspected brain stem death, what do you test?
cranial nerves
