Lab Section 6 Flashcards
where do axons in the basis of the pons go?
to the middle cerebellar peduncle
which cranial nerves can be seen on the pons?
CN 5- CN 8
although 8 is typically considered as part of the medulla
where can CN 7-5 be located?
7: just medial to the vestibulocochlear nerve at the pontine medullary junction
6: in the PM junction medially
5: piercing the middle cerebellar peduncle in the middle of the pons
what does the superior cerebellar peduncle carry?
axons from the deep cerebellar nuclei to the brainstem and the forebrain
what lies deep to the two vestibular areas? what are they located inferior to?
the vestibular nuclei
inferior to the facial colliculi
what is deep to the facial colliculus?
the abducens nucleus and motor axons from the facial nucleus that loop over the abducens nucleus prior to exiting
what are the three markers of transition from the medulla to the pons?
pyramids disappear and are replaced by the striated basis of the pons
vestibular nuclei
blending of ICP with the white matter of the cerebellum
what structures appear at all levels of the pons?
middle cerebellar peduncle, pontine nuclei, superior cerebellar peduncle and the pontine reticular formation
what is the genu of the facial nerve?
the portion that curves around the abducens nucleus
where does the spinal nucleus of CN 5 extend to?
the level of the facial colliculus
what do the raphe nuclei neurons secrete use as neurotransmitters and what do they modulate?
serotonin
modulate responses of the hypothalamic and cerebral neurons
what are noradrenergic neurons within the pons involved with? name one group of these neurons.
autonomic reflexes and pain sensation
Locus Ceruleus
where do the auditory fibers travel through and cross in, post cochlear nuclei?
the trapezoid body (around the area of the medial lemniscus)
where do many of the axons of the trapezoid body terminate? where do they go after that?
in the superior olive
lateral lemniscus
where does the lateral lemniscus terminate?
in the inferior colliculus
what component of CN 5 controls the jaw? which portion processes epicritic information? which portion processes proprioceptive information?
motor nucleus of 5
Principal sensory nucleus of 5 and pontine portion of the spinal nucleus of 5
mesencephalic nucleus of 5
where do axons from the mesencephalic tract of 5 go?
they synapse with the motor nucleus of 5 > reticular formation > cerebellum
where doe sthe medial lemniscus shift in the pons?
shifts further laterally and dorsally while moving more rostrally in the pons and midbrain
what information synapses in the periaqueductal gray matter of the midbrain?
pain and temperature information from the anterolateral system
what does the medial longitudinal fasciculus connect?
the superior colliculus, vestibular nuclei, cranial nerve nuclei 3,4 and 6, and the cervical spinal cord
what does desctruction of the MLF in the pons cause?
horizontal nystagmus and loss of conjugate horizontal eye movements (internuclear opthalmoplegia)
what is normal when the MLF is damaged?
convergence of the two eyes
what does the PPRF do?
coordinates conjugate horizontal eye movements
what are the three predominant outputs for the vestibular nuclei?
the cranial nerve nuclei that move the eyes (MLF)
spinal cord to maintain posture
cerebellum (ICP)- balance and reflexive eye movements
what are the symptoms of vestibular nuclei damage?
nystagmus, balance loss, vertigo and nauseousness
in what way can pathology of CN VII lead to eye damage?
inability to close the eye and loss of PNS control of the lacrimal glands
describe the mechanism of the corneal reflex.
CN V receives noxious input from the irritation to the cornea and CN VII closes the eye
which nerve or nucleus would be damaged with internal strabismus?
abducens nucleus (CN VI)
where do most axons from the spinal nucleus of V terminate?
in the reticular formation
what does epicritic information from the CN V nucleus travel with?
epicritic sensation from the rest of the body in the medial lemniscus
what are the origins and terminations of axons in the inferior cerebellar peduncle? what kind of information does it include?
spinal cord and medulla > cerebellum
proprioceptive information from the body mostly
what three tracts input to the cerebellum via the ICP?
spinocerebellar tracts
inferior olivary complex
vestibular nucleus
from where does the inferior olive receive input?
from the cerebral cortex, the red nucleus and from the spinal cord
what are the origins and terminations of axons in the middle cerebellar peduncle?
carries info from the pons (pontine nuclei) to the cerebellum
what are the origins and terminations of axons in the superior cerebellar peduncle?
carries info from the deep cerebellar nuclei to the tegmentum of the pons right below the inferior colliculus
what happens to the axons immediately after they leave the superior cerebellar peduncle?
they decussate at the decussation of the superior cerebellar peduncle
what are the targets of axons from the superior cerebellar peduncle?
areas of pontine reticular formation
red nucleus
VA and VL nuclei
what are the four deep cerebellar nuclei?
the fastigial, globose, embolliform and dentate nuclei
where do the deep cerebellar nuclei receive most of their input from?
the cerebellar cortex
where do the medial pair of deep cerebellar nuclei receive most of their input from?
from axial related structures like the vestibular nuclei and reticular formation
where do the lateral pair of deep cerebellar nuclei receive most of their input from?
related to distal limb control
midline pathology of the cerebellum affects which muscles? lateral pathology?
axial muscles-affect balance
limb movement
what is ataxia?
difficulty in making coordinated movements not attributable to paralysis
disturbance of balance is a symptom of damage of what cerebellar structures?
vermis or flocculus
T or F: hypotonia is not a common symptom of cerebellar damage.
False
which three symptoms may result from either vestibular or cerebellar pathology?
disturbance in posture, disturbance in balance and nystagmus
