4.4 Midbrain and CN Flashcards
What are the substantia nigra? Where?
Midbrain
dopamine production for movement and emotion
What is the red nucleus? Where?
Midbrain
posture control
What is the superior colliculus? Where?`
Midbrain
visual tracking of objects, visual reflexes
What is the inferior colliculus?
auditory reflex, orient to loud sounds
What are the cerebral peducles?
large white matter tract from cerebrum to spinal cord in midbrain
What are the cerebellar peduncles?
large white matter tract to cerebellum in the midbrain
What is the pons? Fx? CNs?
bulging region between midbrain and medulla, anterior to cerebellum
cranial nerve nuclei (CN V, VI, VII, VIII)
Pneumotaxic respiratory center – works with medulla to maintain rhythmic breathing
cerebellar peduncle white matter tract pons to cerebellum
What are the pyramids of the medulla?
contains corticospinal motor tracts that cross over (decussation) before they continue down the spinal cord
What are the nucleus gracilis and cuneatus? Where?
Medulla
sensory information from limbs to thalamus
What are the olives? Where?
sensory information to cerebellum
What does the medulla control?
cardiac center: heart rate and force of contraction
vasomotor center: blood pressure
respiratory center: respiratory rate, coordination with pons
Vomiting, swallowing, coughing, sneezing, hiccups
What CN nuclei are in the medulla?
IX, XI, XII
What is a diffuse axonal injury?
DAI- widespread white matter damage, diffuse swelling of axons, hemorrhage or damage to corpus callosum, brainstem
rapid stretch of axons, loss of elasticity, axonal swelling and disconnection, calcium entry cell death
loss of consciousness, persistent coma, severe impairment likely
rule out cervical spinal injury
What is a concussion?
mild TBI, traumatic force with or without loss of consciousness, changes in the brain with no evidence of structural abnormality
metabolic dysfunction of neurons, excessive glutamate accumulation, swelling of neurons that resolves over time
confusion, headache, dizziness, flat affect, lack of coordination, imbalance, brief amnesia
What is a cerebral contusion?
sx?
bruise” of the brain, scattered bleeding on surface of brain
vascular and tissue damage, swelling of tissue, increased intracrranial pressure, loss of consciousness
severe headache, dizziness, vomiting, change in one pupil, restlessness, agitation, irritability, memory loss, drowsiness, confusion, decreased respiration, decreased heart rate, hypertension
What is a cerebral hematoma? Sx?
bleeding in epidural or subdural spaces most severe TBI complication and major cause of death
fracture lacerates arteries or veins in meninges region
severe headache, vomiting, seizure, may or may not lose consciousness, can be progressive, fluctuating, dilated, sluggish or fixed pupils, positive Babinksi sign, hypertension, bradycardia, bradypnea
What is CN I?
sensory smell
group of neurons from nasal cavity to olfactory bulb
through cribiform plate of ethmoid bone
damage: anosmia (lack of smell)
What is CN II?
sensory vision
from retina of eye to optic chiasm
through optic canal of sphenoid bone
damage: anopsia (lack of vision)
What is CN III?
motor: upper eyelid, 4/6 eye muscles (inferior rectus, superior rectus, medial rectus, inferior oblique)
autonomic motor: sphincter pupillae muscle of iris (constricts pupil), ciliary muscle of lens (near vision)
superior orbital fissure of sphenoid bone
damage: ptosis (eyelid droop), strabismus (eyes not parallel), diplopia (double vision), difficulty focusing
What is CN IV?
motor: superior oblique eye muscle, moves eye inferior/laterally (pulls back of eyeball up)
superior orbital fissure of sphenoid bone
damage: strabismus (eyes not parallel), diplopia (double vision
What is CN V?
Trochlear
Opthalmic (V1):
sensory anterior scalp, forehead, cornea, meninges
superior orbital fissure
Maxillary (V2):
sensory nasal mucosa, hard palate, gums, cheeks, meninges
foramen rotundum
Mandibular (V3):
sensory anterior 2/3 tongue, chin, jaw, teeth, ear & motor (chewing, swallowing) masseter, pterygoids, mylohyoid, digastric, tensor tympani, tensor veli palatini muscles
foramen ovale
damage: loss of facial sensation, loss of corneal reflex, weakening of jaw muscles, trigeminal neuralgia (intense, pulsating pain)
What is CN VI?
Abducens
motor: lateral rectus eye muscle
superior orbital fissure
damage: limited lateral movement of eye, diplopia (double vision)
What is CN VII?
motor: 5 motor branches to muscles of facial expression, digastric, stylohyoid, stapedius muscles
stylomastoid foramen
autonomic: lacrimal and salivary glands
internal acoustic meatus
sensory: taste, anterior 2/3 tongue
damage: dry eye, dry mouth, decreased taste, facial paralysis, difficulty closing eyelid, sagging corner of mouth
What is Cn VIII?
. Vestibulocochlear
sensory: hearing and equilibrium
from cochlea, semicircular canals to internal acoustic meatus
damage: loss of hearing, loss of balance, nausea, vomiting, dizziness
What is CN IX?
. Glossopharyngeal
sensory: taste and sensation of posterior 1/3 tongue
motor: swallowing, pharynx muscle
autonomic: parotid salivary gland
damage: dry mouth, decreased taste
What is CN X?
Vagus
sensory: heart, lungs, abdominal organs, eardrum, external acoustic meatus larynx, laryngopharynx
motor: pharynx, larynx
autonomic: heart, lungs, pharynx, larynx, trachea, abdominal organs
jugular foramen
damage: loss of voice, hoarse voice, difficulty swallowing, decreased GI motility
What is CN XI?
motor: trapezius and sternocleidomastoid, travels with CNX to pharynx
jugular foramen
damage: difficulty elevating shoulder, difficulty turning head
What is CN XII?
Hypoglossal
muscles of the tongue
hypoglossal canal
damage: impaired tongue movement, difficulty swallowing, difficulty speaking, deviation of tongue to one side
