Medulla Oblongata Flashcards
What is the medulla oblongata a derivative of?
the myelencephalon
What is the fasciculus cuneatus?
an ascending sensory tract
Where does the fasciculus cuneatus originate from?
spinal cord segments C1-T5
Where does the fasciculus cuneatus terminate?
the thalamus
What somatic sensory function is the fasciculus cuneatus in charge of?
proprioception and touch
What regions of the body does the fasciculus cuneatus receive information from?
the cervical area, upper trunk, and the thoracic limb
What is the spinal tract of the trigeminal nerve?
a descending sensory tract
Where does the spinal tract of the trigeminal nerve originate?
in the face
Where does the spinal tract of the trigeminal nerve terminate?
in the nucleus of spinal tract V
What is the somatic sensory function of the spinal tract of the trigeminal nerve?
facial pain and temp
What is the pyramid?
a descending motor tract
Where does the pyramid originate?
cerebral motor cortex
Where does the pyramid terminate?
the brain stem and the spinal cord
What cranial nerves originate in the medulla oblongata?
CN VI - CN XII
Where does the abducent nerve terminate?
in the lateral rectus and retractor bulbi
What does injury to the abducent nerve cause?
medial strabismus
What reflex is absent when the abducent nerve is damaged?
3rd eyelid reflex
Where does the facial nerve originate from?
the trapezoid body
What type of fibers does the facial nerve have?
somatic motor, visceral motor, and sensory
What do the somatic motor fibers of the facial nerve control?
blinking and the muscles of facial expression
What do the visceral motor fibers of the facial nerve control?
the lacrimal gland and salivary glands
What sensory information does the facial nerve receive?
taste from the rostral 2/3 of the tongue
What reflexes are absent if the facial nerve is damaged?
spontaneous blinking, the palpebral reflex, and the corneal reflex
What will a lesion to the visceral motor fibers of the facial cause?
lack of tear and saliva production
What will a lesion to the sensory fibers of the facial cause?
lack of sensory information from the tastebuds
What nerve controls the sensory portion of the corneal reflex?
the trigeminal
What nerve controls the motor portion of the corneal reflex?
the facial and the abducent
What nerve controls the sensory portion of the palpebral reflex?
the trigeminal
What nerve controls the motor portion of the palpebral reflex?
the facial nerve
What type of fibers does the vestibulocochlear nerve have?
afferent
Where do fibers from the vestibular organ go?
to the vestibular nuclei
Where do fibers from the vestibular nuclei go?
to the vestibulospinal tract
Where do fibers from the vestibulospinal tract go?
to the skeletal muscles that the vestibulocochlear nerve innervates
What does the vestibular part of the vestibulocohlear nerve control?
eye movement in response to change in head position and adjust body position in response to change in head position
Where do fibers from the cochlear nuclei go?
dorsally to the acoustic stria and ventrally to the trapezoid body
What does the cochlear part of the vestibulocochlear nerve do?
provides auditory input
What is the lateral lemniscus?
a tract from the cochlear nuclei
What does the lateral lemniscus send fibers to?
the medial geniculate nucleus of the thalamus and the caudal colliculus of the midbrain
What are the auditory structures of the medulla?
cochlear nuclei, acoustic stria, and trapezoid body
What are some clinical signs that are associated with a lesion to the vestibulocochlear nerve?
abnormal nystagmus, head tilting, falling, and circling
What does the quick phase of abnormal nystagmus indicate?
what side the lesion is on - it will go away from the lesion
If a patient is head tilting to the right, where is the lesion?
on the right vestibulocochlear nerve
If a patient is circling to the right, where is the lesion?
on the right vestibulocochlear nerve
What kind of information does the nucleus of the solitary tract get and from what cranial nerves?
sensory information from the vagus and glossopharyngeal
What type of nucleus is the nucleus ambiguous?
motor
What nerves are associated with the nucleus ambiguous?
the vagus, glossopharyngeal, and accessory
What does the nucleus ambiguous send motor innervation to?
the pharynx, larynx, palate, and esophagus
What does the motor nucleus of the accessory nerve do?
it innervates the trapezius, cleidocervicalis, sternocephalicus, and cleidomastoideus to keep the head up
What cranial nerves are associated with the swallowing reflex?
CN IX, X, and XI
What nucleus is involved in the sensory stimulation of the swallowing reflex?
nucleus of the solitary tract
What nucleus is involed in the motor part of the swallowing reflex?
nucleus ambiguous
What is peristalsis?
the contraction of smooth muscle that moves things from one end to the other
What is dysphagia?
difficulty swallowing and lack of esophageal peristalsis
What can lack of esophageal peristalsis be caused by?
deficit in sensory input and motor control
What can lack of esophageal peristalsis lead to?
mega esophagous
How does the vestibular nuclei innervate the extraocular muscles?
via the medial longitudinal fasciculus
