Motor system,spinal cord and brainstem L10 Flashcards
Three parts of brainstem
midbrain
pons
medula
Where do the nerves emerge from in the midbrain
interpeduncular fossa
which cranial nerves are in the forebrain
1, 2
which cranial nerves in the midbrain
3,4
which cranial nerves in the pons
5,6,7,8
Which cranial nerves in the medulla
9,10,11,12
What is the channel through the midbrain called
cerebral aqueduct
What lies behind the cerebral aqueduct
tectum
What are the ridges along the medulla called
the pyramids
the 4 bumps (six pack) of the midbrain (tectum) are
superior and inferior colliculi
Which cranial nerve is the only one to come out of the dorsal aspect of the CNS
4th
upper motor neurons lie
entirely in the CNS
3 places UMN can originate from
Cerebral cortex,
cerebellum,
brainstem
LMN lie in
The PNS
LMN can be (2) nerves
spinal nerves and cranial nerves
A LMN action potential is
all or nothing
What can effect LMN
UMN
What tracts pass through the internal capsule
Ascending and descending
Where is a dangerous place to be damaged in the brain (affects a lot of function)
Internal capsule
4 features of the internal capsule
An anterior limb
A genu (bend)
Posterior limb
Retrolentiform area
Shape of the internal capsule
2 V shapes
What do the ventromedial tracts affect
posture and girdle muscles (trunk muscles and limb girdles)
What do the dorsolateral tracts control
Distal movement and fine movement
What 2 classifications can be made about descending tracts
ventromedial
Dorsolateral
name three ventrolateral tracts
pontine
tectal
vestibular
Name three dorsolateral tracts
Cortical
rubral
medullary
The pontine reticulospinal tract runs from
Supplementary motor cortex–> pontine reticular nuclei
The pontine reticulospinal tract runs down the spinal cord
ipsilaterally
The pontine reticulospinal tract synapses in______
in multiple segments of spinal cord = polysegmental
What does the reticulospinal tract mediate
large movements of the trunk and limbs
What extra thing does the reticulospinal tract mediate
sensation (e.g pain can force yourself to hold hand over flame)
What category of tract is tectospinal
ventromedial
Where does the tectospinal tract run from
superior and inferior colliculus (tectum)—-> cervical spinal cord
What place does the visual pathway come from (tectospinal)
superior colliculus
What place does the auditory pathway come from (tectospinal)
inferior colliculus
When does the tectospinal tract desiccate
early
What muscles does the tectospinal tract control
head and neck
What does the superior colliculus receive inout from
the optic nerve
Where do most vestibulospinal tracts come from
vestibular nuclei in the pons
How do the vestibulospinal tracts travel down the spinal cord
ipsilateral
What does the vestibulospinal tract control
balance and posture
Where do vestibulospinal tracts run to
all spinal segments (anti-gravity muscle)
Ventromedial tracts are about
posture, position and keeping you off the ground (proximal muscles)
Name 2 dorsolateral descending tracts
Corticospinal
rubrospinal
Where does the rubrospinal tract come from
the red nucleus
Where does the rubrospinal tracts decussate
as they emerge from the red nucleus (which is in the midbrain)
How does the rubrospinal tract travel down the spinal cord
contralaterally
What is the rubrospinal tract important in
control and coordination of movement
What type of tract is corticospinal
pyramidal (also dorsolateral)
The corticospinal tract comes from the
motor cortex areas
Which structure does the corticospinal tract run down
the internal capsule
Where in the internal capsule does the corticospinal tract run
in the posterior limb
3 places neurons of the corticospinal tract pass
crus cerebri
the pons
medulla
Where in the pons do the corticospinal tracts run
front (basilar) pons
where do 85-90% of the fibres decussate in the corticospinal tract
medullary pyramids
What do the decussated corticospinal tracts become
lateral corticospinal tract
What do the non decussated corticospinal tracts become
anterior cortical spinal tract
Where do the UMN of the lateral corticospinal tracts synapse
ventral horn at all segmental levels
What happens to the anterior corticospinal tract
remains ipsilateral in the spinal cord, decussates and terminates in the ventral horn of the cervical and upper thoracic segmental levels
What is the corticospinal tract important for (2)
voluntary skilled motor activity (especially upper limbs)
independant flexion of single distal joints
Babinski’s
toe curl up (normally down) / extension
dorsolateral=
fine muscle control
