Chapter 5: The Brain Stem (continued) Flashcards
Describe the course the accessory nucleus takes.
accessory nucleus is found in the cervical spinal cord.
- axons of the spinal accessory nerve arise from the accessory nucleus, pass through the foramen magnum to enter the cranial cavity, and join the fibers of the vagus to exit the cranial cavity through the jugular foramen
What does the curve of the facial nucleus form?
the internal genu of the facial nerve
What is the purpose of the superior olivary nucleus?
recieves auditory impulses from both ears by way of the cochlear nuclei
Where is the main sensory nucleus of pons located?
just lateral to the motor nucleus of pons where trigeminal motor neurons are transmitted
What is the purpose of the main sensory nuceus of the pons?
receives tactile and pressure sensation from the face, scalp, oral cavity, nasal cavity and dura
What is the spinal trigeminal nucleus?
a caudal continuation of the main sensory nucleus
Where does the spinal trigeminal nucleus extend?
from the mid pons through the medulla to the cervical cord
What is the purpose of the spinal trigeminal nucleus?
central processes from cells in the trigeminal ganglion conveying pain and temperature sensation from the face descend in the spinal tract of V and synapse on cells in the spinal nucleus
What part of the thalamus relays touch, pain, temperature (CN V) and taste (CN VII, IX) sensations from the face to cortex?
VPM
Where is the mesencephalic nucleus located?
at the point of entry of the fifth nerve and extends into the midbrain
Purpose of the mesencephalic nucleus?
recieves proprioceptive input from joints, muscles of mastication, extraocular muscles, teeth, and the periodontium
Label figure III.5.5 include note at bottom
What is another name for corticobulbar innervation of cranial nerve nuclei?
Corticonuclear innervation of CN nuclei
What is the purpose of corticobulbar fibers?
serve as the source of upper motoneuron innervation of the LMN in CN nuclei
Corticobulbar innervation of facial motoneruons to muscles of the upper face is contralateral or bilateral?
bilateral
UMN of corticobulbar fibers that innervate the upper face are responsible for what action of the face?
wrinkling of the forehead and shutting the eye
Corticobulbar tract innervation to the lower part of the face is bilateral or contralateral?
contralateral
Cortiocbulbar innervation to the lower part of the face innervates which structure?
muscles of the mouth
Bells palsy cause and presentation?
facial nerve lesion
complete ipsilateral paralysis of muscles of facial expression, including an inability to wrinkle the forehead or shut the eyes and a drooping of the corner of the mouth
Presentation of a lesion of corticobulbar nerves to the tongue muscles?
lesion of the left will cause deviation of tongue to the right
Label the structures of the inner ear.
What does the spiral ganglion contain?
contains cell bodies whose peripheral axons innervate auditory hair cells of the organ of Corti
Why do middle ear diseases result in conductive hearing loss?
because of a reduction in amplification provided by the ossicles
What are some middle ear disease?
otitis media, otosclerosis