EXAM 3 - Mesencephalon

what part of the mesencephalon contains the superior and inferior colliculi

tectum

what surrounds the cerebral aqueduct

periaqueductal gray

what is posterior to the cerebral aqueduct

tectum

what is anterior to the cerebral aqueduct

cerebral peduncles

what CN origins are found in the periaqueductal gray

3 and 4

what structures are included in the cerebral peduncles

tegmentum, substantia nigra, and crus cerebri

what part of the cerebral peduncle is white matter

crus cerebri

what part of the cerebral peduncle is gray matter

substantia nigra

know this diagram of the mesencephalon

what type of reflexes are associated with the superior colliculi

visual

is superior colliculi reflex voluntary or involuntary

involuntary

what tract arises form the superior colliculus and what does it do

tectospinal, move head away from objects moving rapidly through field of vision

what muscles are contracted via tectospinal tract

traps and SCM

will damage to the tectum result in loss of vision

NO, decrease ability to respond to objects moving through vision field

what info do the inferior colliculi relay? where?

auditory info to the thalamus

what is the opening for CSF to flow from 3rd to 4th ventricle

cerebral aqueduct

what is produced in the periaqueductal grey

endorphins and enkephalins

where is the apparent origin for CN 3

interpeduncular fossa

what muscles are controlled by the occulomotor nuclei

superior, medial, and inferior rectus, inferior oblique, and levator palpebrae superioris

what muscles are controlled by accessory occulomotor (Edinger-Westphal's)

ciliary muscles and sphincter pupillae

what muscle is supplied by the trochlear nerve (CN4)

superior oblique muscle

what is the origin of CN4

posterior side of brainstem

what is unique about the fibers of CN 4

left and right fibers cross at apparent origin

if superior oblique muscle is contracted, what movement occurs

eye will turn down and out

what parts of the midbrain contain periaqueductal grey

tectum and tegmentum

what CN are located in tegmentum in the periaqueductal grey

3 and 4

where is the reticular formation of the midbrain located

in tegmentum

what tract is found in the tegmentum that carries 2 pt touch, vib, kin info to the VPL of thalamus

medial lemniscus

what nucleus is found int he tegmentum

red nucleus

what is the parvocellular portion of the Red Nucleus

highly vascular, superior, extends into subthalamus

what is the magnocellular portion of the red nucleus

inferior, large, most fibers here, smaller in humans

the red nucleus receives input fibers from where

cerebellar nuclei (dentate and interposed (globose and emboliform))

what is the name of the gray matter between tegmentum and crus cerebri

substantia nigra

what is produced in the substantia nigra and what is it made from

dopamine from tyrosine

damage to the substantia nigra can result in what condition? what is a treatment?

Parkinson's, dopamine

can dopamine cross BBB

NO, use L-dopa

the substantia nigra acts as a place where information is exchanged between what two nuclei

caudate and putamen

what type of axons does Crus Cerebri contain

pyramidal axons (UMNs)

what is corticomesencephalic

cortex to midbrain to CN 3 and 4

what is corticopontine

cortex to pons

what is corticobulbar

cortex to medulla

what is corticospinal

cortex to spinal cord

what movement is initiated by corticomesencephalic fibers

voluntary eye movement because the fibers terminate on CN 3 and 4

what movement do axons of crus cerebri initiate

skilled voluntary movement