Brain stem Flashcards
what are the key features of the midbrain?
7 of them
superior and inferior colliculi cerebral peduncles cerebral aqueduct red nucleus substantia nigra CN III and CN IV
what are the key features of the pons?
8 of them
pons proper middle cerebral peduncle Fourth ventricle basilar artery CNs V, VI, VII, VIII
what are the key features of the medulla?
8 of them
4th ventricle pyramid olive vertebral arteries CNs VIII,IX,X,XI,XII
Midbrain
oculomotor nucleus
type of nucleus, innervations and what happens if damaged?
somatic motor to Levator palpabrae superioris, superior, medial, inferior rectus muscles, and inferior oblique muscle
damage: causes ptosis(dropping of upper eyelid) and eve deviating down and out
Midbrain
Edinger-Westphal nucleus
type and innervation
relfex
visceral motor (parasympathetic) innervation is pupillary constrictor and ciliary muscles pupillary light reflex
Midbrain
Trochlear nucleus
type and innervation
damage result
- somatic motor to the superior oblique muscle
- damage prevents patients looking in and down
Pons
Trigeminal motor nucleus
type and innervation
damage result
- branchial motor to muscles of mastication
- damage causes weakness in jaw clinching and deviation to side of lesion while opening of jaw; jaw jerk reflex
- *jaw goes to same side as damage**
Pons
abducens nucleus
type and innervation
damage result
- somatic motor to the lateral rectus muscle
- damage results in double vision when looking laterally on side of lesion
Pons
Facial motor nucleus
type and innervation
damage result
Branchial muscles of facial expression
-damage(nuclear and infranuclear) causes ipsilateral Bells palsy, corneal reflex.
Supranuclear damage results in contralateral Bells palsy with sparing of forehead
Pons
Superior salivatory nucleus
type and innervation
damage result
Visceral motor(parasymp) to the lacrimal, nasal, palatal, submandibular salivary and sublingual salivary glands -damage: causes dry eye, dry mucous membranes, dry mouth.
Medulla
Hypoglossal nucleus
type and innervation
damage result
-Somatic motor to the muscles of the tongue
-damage causes the tongue to deviate to the side of the lesion when tongue is protruded
“lick your wounds”
Medulla
nucleus ambiguus
type and innervation
damage result
Branchial motor to palatal, pharyngeal and laryngeal muscles
-damage causes soft palate to deviate contralaterally when gag reflex is elicited; swallowing difficulties; hoarse voice, gag reflex
Medulla
Dorsal vagal nucleus
type and innervation
damage result
Visceral motor (para) to thoracic and abdominal viscera to the transverse colon -damage causes reduction in parasympathetic innervation
Medulla
Inferior salivatory nucleus
type and innervation
damage result
Visceral motor(para) to the parotid gland -damage alone will likely result in no symptoms
the quadrigeminal plate or tectum consists of what paired bodies and what is their function and where are they found?
superior colliculus: preliminary visual processing
inferior colliculus: auditory processing
-found on the posterior aspect of the midbrain
what is the function of the cerebral peduncles(crus cerebri) and where are they located?
relay for cortico-spinal, cortico-pontine, and cortico-bulbar tracts
-they are found just lateral and anterior to the calliculi and wrap around to the anterior
what is found in the midbrain that has the function of transporting CSF from the 3rd ventricle to the 4th ventricle?
cerebral aqueduct aka mesencephalic aqueduct or aqueduct of sylvius
what is found in the midbrain at the level of the superior colliculi that is involved in motor coordination and is considered an extrapyramidal system?
red nucleus
where is the supstantia nigra found and what is it involved in?
found the the midbrain
involved in movement and reward (addiction)
*parkinsons disease and another extrapyramidal system
what tracts are found within the pons proper?
where is the pons proper on a crossection?
corticospinal and cerebellar tracts
found on the most anterior portion of the fat belly (pons)
What is found within the middle cerebellar peduncle and what is its location relative to the pons proper?
contains fibers that arise from the contralateral pontine nuclei and end in the cerebellum
-located just lateral and posterior to pons proper
where is the fourth ventricle found and what is in it?
within the pons and contains CSF
Communicates w/ subarachnoid space via median and lateral apertures
basilar artery formed by what arteries and what comes of it?
formed by the vertebral arteries
branches: AICA, pontine arteries, Superior cerebellar artery and posterior cerebral artery
runs right down the middle of the anterior pons
where are the pyramids found and what is in them?
they are found in the medulla
decussation of corticospinal tract
most anterior and medial portion of medulla
the olive contains fibers that go where and what CN exists between the pyramid and olive?
the fibers course to the cerebellum
the CN XII or hypoglossal exits between them
what branches come off the vertebral arteries and what do the two vertebral arteries form when the connect?
Posterior inferior cerebellar artery (PICA)
the basilar artery is formed when the two vertebral arteries connect(this occurs just rostral to the medulla)
why is the CN VIII vestibulocochlear nerve found in both the pons and medulla?
because it has nucleus that descends to the medullar from the pons
which muscles are considered branchial, which arch do they come from and what nerve innervates them?
muscles of mastication, 1st arch, CN V
muscles of facial expression, 2nd arch, CN VII
stylopharyngeus, 3rd arch, CN IX
palatal, pharyngeal, and laryngeal, 4th and 6th arch, CN X
with regard to the sulcus limitans where are the sensory nuclei and where are the motor nuclei?
the sensory and always lateral and the motor is always medial
what two nuclei are found in the rostral portion of the midbrain?
oculomotor nucleus and Edinger-Westphal nucleus
what nucleus is found in the caudal portion of the midbrain?
the trochlear nucleus
