Lecture 9b- Cranial Nerves 5, 7, 9, 10, 11, 12 Flashcards
What nerve is CN5?
trigeminal
CN5 has somatosensory neurons from skin, muscle, and joint conscious sensor receptors of the anterior / head.
2/3
CN5 has somatomotor neurons to muscles of __________ and tempor tympani.
mastication
What is the sensory pathway of CN5?
- cutaneous sensation from upper (opthalmic), middle (maxillary), and lower (mandibular) branches of CN5
- trigeminal (semilunar) ganglion
- trigeminal nerve
- trigeminal sensory nuclei
- most cross near level of secondary nucleus
- VPM of thalamus
- infereior postcentral gyrus
The opthalmic branch of CN5 goes through what fissure and supplies what structures?
- superior orbital fissure
- forehead, cornea, upper eyelid, dorsum of nose
The maxillary branch of CN5 goes through what foramen and supplies what structures?
- foramen rotundum
- lower lid, lateral nose, cheek, upper jaw/teeth, palate, upper lip
The mandibular branch of CN5 goes through what foramen and supplies what structures?
- foramen ovale
- lower lip, lower jaw/teeth, tongue, chin
The trigeminal (semilunar) ganglion contains the _____ of psuedounipolar primary sensory neurons and is located at the base of the __________.
- soma
- sella turcica
The trigeminal nerve is the central axons of psuedounipolar sensory neuron and connects at the _______.
pons
The trigeminal sensory nuclei is where we synapse to get our __________ neuron.
secondary
The central axons carrying pain and temperature signals from face _______ from pons to the _______ and synapse with ____________________ nucleus.
- descend
- medulla
- spinal trigeminal
The central axons carrying touch and proprioception signals from the face synapse with ________________ nucleus in the ______.
- main sensory
- pons
The central axons carrying proprioception from the jaw synapse with the _________________ nucleus in the _____.
- mesencephalic
- pons
Most sensory pathways of CN5 cross near the level of the _______ nucleus and ascend in ___________ but some remain uncrossed.
- secondary
- trigeminal lemniscus
Sensory information from the trigeminal nerve goes to the ________- of the thalamus.
VPM
Where does the secondary neuron of the trigeminal nerve synapse with the tertiary neuron?
synapses at VPM
Where does the tertiary neuron of the trigeminal nerve go?
inferior postcentral gyrus
What is the motor pathway of CN5?
- right and left precentral gyrus=upper motor neuron
- corticobulbar tract
- crossed and uncrossed, bilateral input to motor nucleus trigeminal nerve=lower motor neuron
- trigeminal nerve
- runs with mandibular nerve to muscles of mastication, mylohyoid, anterior belly digastric, tensor tympani
The upper motor neuron of the trigeminal nerve comes from the _________ homunculus at the precentral gyrus.
lateral
Is the motor pathway of CN5 involved with the corticobulbar or corticospinal tract?
corticobulbar (muscles of face, head, and neck)
The motor neurons of CN5 are both _________ and __________, with bilateral input to motor nucleus of __________ nerve=_______________.
- crossed and uncrossed
- trigeminal
- lower motor neuron
The trigeminal nerve runs with the ________ nerve to what muscles?
- mandibular
- muscles of mastication, mylohyoid, ant belly digastric, tensor tympani
GUSTATION (TASTE)
GUSTATION (TASTE)
Taste results from a ______ interaction between molecules in mouth and membrane ______ receptors on receptor cells in _________=sensory organ
- chemical
- chemo
- taste buds
Taste buds are located in the papillae of what 4 structures?
- tongue
- soft palate
- pharynx
- larynx
Taste buds are composed of what 2 cells?
- gustatory receptor cells (hair cells)
- basal cells
Gustatory receptor cells have long ___________ (gustatory hair) which extends to the surface through the taste _____; dendrites of cranial nerves synapse on gustatory receptor cells, in this case receptor cells ______ neurons.
- microvilli
- pore
- are not
Basal cells are stem cells that develop into gustatory receptor cells and have a life span of ________
10 days
- Receptors in the tip of the tongue are more sensitive to _______.
- Receptors in the posterior tongue are more sensitive to _______.
- Receptors in the lateral tongue are more sensitive to _______.
- sweet
- bitter
- sour and salty
-This is the traditional view, the current view is that taste sensations arise from all regions
Like olfactory stimuli, we decrease our sensitivity to particular taste stimuli, what is this called? How long before we have complete…?
- adaptation
- 1-5m for complete adaptation
What are the 9 parts of the gustatory pathway?
- bite of food is chewed and dissolved into food molecules
- food molecules dissolve in saliva
- food molecules bind receptor on gustatory receptor hair cell
- chemical messenger binds chemical gated channel on dendrite of pseudounipolar taste neuron
- AP generated on peripheral process of pseudounipolar neuron of CN7,9, or 10
- sensory ganglia for taste=primary sensory neuron (CN7=anterior 2/3 tongue; CN9=posterior 1/3 tongue; CN10=base of tongue/pharynx
- central process enter the brain stem and travel in solitary tract
- synapse on secondary neurons in the gustatory portion of solitary nucleus=secondary sensory neuron which projects crossed/uncrossed to tertiary neurons in VPM nucleus of thalamus (taste differentiation) and limbic system (emotional response to taste)
After food is dissolved into food molecules, the food molecules binds to receptors on ______________ cell.
gustatory receptor hair
Gustatory receptor hair cells release _______________ after food molecules bind to them.
-chemical messengers
Chemical messengers released from gustatory hair cells bind to chemical gated channels on dendrite of _______________ taste neuron.
pseudounipolar
AP are generated on the ________________ of pseudounipolar neuron of CN_,_, and __.
- peripheral
- 7,9,10
The ______________ is a sensory ganglion of the facial nerve (CN7). It contains the cell bodies of the fibers responsible for conducting taste sensation from the anterior two-thirds of the tongue.
geniculate ganglion
The _____________ is a sensory ganglion of the glossopharyngeal nerve (CN9). It contains the cell bodes of the fibers responsible for conduction taste sensation from the posterior one-third of the tongue.
inferior petrosal ganglia
The _____________ is a sensory ganglion of the vagus nerve (CN10). It contains the cell bodes of the fibers responsible for conduction taste sensation from the base of the tongue/pharynx.
inferior ganglia of CN10
The central process of the primary sensory neuron for taste enter the brain stem and travel on __________ tract.
solitary
The primary sensory neuron for taste synapses with the secondary neuron in the __________ portion of the solitary nucleus. The secondary neuron projects _________/_______ bilateral to these two structures:
- ) Tertiary neuron located in the _______ nucleus of the thalamus and go to the bilateral cerebral cortex (________,__________) for taste __________.
- ) _______ system for ________ response to taste
- gustatory
- crossed/uncrossed
- VPM
- insula, inferior postcentral gyrus
- differentiation
- limbic
- emotional response
CN7=FACIAL NERVE
CN7=FACIAL NERVE
What nerve is CN7?
facial
What are the 4 neuron types of CN7?
- special sensory for taste=pseudounipolar
- somatosensory for proprioception of facial expression muscles; skin sensation posterior ear, external auditory meatus=pseudounipolar
- somatamotor to muscles of facial expression and stapedius
- autonomic motor (preganglionic parasympathetic)
What is the somatosensory pathway of CN7?
- receptors for proprioception of facial expression muscles; skin sensation posterior ear, external auditory meatus= pseudounipolar
- geniculate ganglia located in petrous portion of temporal bone = primary sensory neuron
- spinal (trigeminal) nuc. of CN5 = secondary sensory neuron
- VPM of thalamus = tertiary sensory neuron
- Ascend to contralateral postcentral gyrus = crossed
Where are the 3 synapses located on the somatosensory pathway of CN7?
1st= geniculate ganglia
2nd= spinal (trigeminal) nuclei of CN5
3rd=VPM of thalamus
CN7 also has _______ sensory for taste
special
What is the somatomotor pathway of CN7 to muscles of facial expression?
- precentral gyrus = upper motor neuron
- corticobulbar tracts
- facial nucleus = lower motor neuron at level of open medulla (upper facial muscles get bilateral (crossed and uncrossed))(lower facial muscles get contralateral (crossed only))
- CN7 exits brainstem at junction of pons and medulla; leaves cranial cavity via stylomastoid foramen and divides into cutaneous nerves of parotid plexus providing motor to muscles of facial expression
What are the 6 somatomotor distal branches of CN7 that provide motor to muscles of facial expression
- auricular n
- temporal branch
- zygomatic branch
- buccal branch
- marginal (mandibular) branch
- cervical branch
In regards to the CN7 somatomotor pathway, upper facial muscles get _______ and lower facial muscles get ____________.
- bilateral (crossed and uncrossed)
- contralateral
CN7 somatomotor pathway leaves the cranial cavity at the junction of the ____ and _______. It leaves the cranial cavity via the ___________ foramen.
- pons and medulla
- stylomastoid
How does part of CN7 somatomotor pathway reach the stapedes muscle?
branch of CN7 enters petrous portion of temporal bone through internal acoustic meatus to innervate the stapedes
What is the autonomic motor pathway of CN7 to lacrimal glands and submandibular/sublingual glands?
- superior salivary nuc = parasympathetic preganglionic neurons in rostral open medulla
- parasympathetic postganglionic cells in pterygopalatine and submandibular ganglia
In regards to the CN7 autonomic motor pathway, pterygopalatine ganglia supplies _______ glands, while the submandibular ganglia supplies _________ glands.
- lacrimal
- sumbandibular and sublingual salivary glands
CN9=GLOSSOPHARYNGEAL NERVE
CN9=GLOSSOPHARYNGEAL NERVE
What nerve is CN9?
glossopharyngeal
What are the 5 neuron types of CN9?
- somatosensory from posterior ear
- special sensory for taste
- visceral sensory from carotid sinus and body
- somatomotor to stylopharyngeous muscle
- autonomic motor (preganglionic parasympathetic) to salivary glands
What is the somatosensory pathway of CN9?
-somatosensory from base of tongue posterior ear
-superior ganglion of CN9 = primary sensory neuron
-spinal (trigeminal) nucleus of CN5 = secondary sensory neuron
-goes to either sensory part of gag reflex w/ CN10
OR
-VPM of thalamus and crossed postcentral gyrus
The somatosensory pathway of CN9 comes from the ________ ear.
posterior
What are the 2 end points of the somatosensory pathway of CN9?
- sensory part of gag reflex w/ CN10
- VPM to postcentral gyrus crossed
CN9 also has _______ sensory for taste.
special
What is the visceral sensory pathway of CN9?
- carotid body and sinuses
- solitary nucleus
- cardiovascular reflex w/ CN10
What is the somatomotor pathway of CN9 to the stylopharyngeus?
- precentral gyrus = upper motor neuron
- corticobulbar tracts
- nucleus ambiguous in medulla = lower motor neuron
- stylopharyngeus
What is the autonomic motor pathway of CN9 to the parotid gland?
- inferior salivary nuclei in medulla
- otic ganglia = preganglionic neuron
- parasympathetic postganglionic neuron in wall of parotid gland
- parotid gland secretory cells
CN10=VAGUS (WANDERING) NERVE
CN10=VAGUS (WANDERING) NERVE
What nerve is CN10?
vagus
What are the 5 neuron types of CN10?
- somatosensory from posterior ear and external auditory canal
- viscerosensory from organs of thorax and abdomen; aortic arch baro and chemo receptors
- special sensory from taste buds on epiglottis and pharynx
- somatomotor to pharyngeal and laryngeal muscles + palatoglossus of tongue
- autonomic motor (preganglionic parasympathetic) to organs of thorax and abdomen
What is the somatosensory pathway of CN10?
- posterior ear and external auditory canal
- superior (jugular) ganglion of CN10 = primary pseudounipolar neuron
- spinal (trigeminal) nucleus of CN5
- VPM of thalamus
- contralateral postcentral gyrus
The somatosensory pathway of CN10 comes from the ___________ ear and ______________ canal.
- posterior
- external auditory
CN10 also has ________ sensory for taste.
special
What is the visceral sensory pathway of CN10?
- aortic arch baro and chemoreceptors
- inferior (no dose) ganglia of CN10
- solitary nucleus
- reflex cardiovascular control w/ dorsal motor nucleus of CN10
The viscerosensory pathway of CN10 comes from the _______ and ________ receptors.
chemo and baroreceptors
What is the somatomotor pathway of CN10?
- precentral gyrus = upper motor neuron
- corticobulbar
- nucleus ambiguous = lower motor neuron
- muscles of pharynx, larynx, and palatoglossus
The somatomotor pathway of CN10 goes to the muscles of the _______ and ________, as well as
- pharynx and larynx
- palatoglossus
What is the autonomic (parasympathetic) motor pathway of CN10?
- dorsal motor nucleus = preganglionic neuron
- postganglionic neuron in wall of organ of innervation
- neck, thorax (heart, lungs), abdominal organs
CN11=SPINAL ACCESSORY NERVE
CN11=SPINAL ACCESSORY NERVE
What nerve is CN11?
spinal accessory
What is the only neuron type of CN11?
somatomotor to SCM and trapezius
What is the somatomotor pathway of CN11?
- precentral gyrus = upper motor neuron
- corticospinal tract
- cross over in decussation of pyramids
- ventral horm C1-C5,6 = lower motor neuron
- spinal accessory n. ascend vertebral canal
- enter cranium via foramen magnum
- exit cranium via jugular foramen
- trapezius and SCM
The somatomotor pathway of CN11 goes to what muscles?
- SCM
- trapezius
CN12=HYPOGLOSSAL NERVE
CN12=HYPOGLOSSAL NERVE
What nerve is CN12?
hypoglossal
What is the only neuron type of CN12?
Somatomotor to intrinsic and extrinsic muscles of tongue (except palatoglossus, CN10)
What is the somatomotor pathway of CN12?
- precentral gyrus = upper motor neuron
- corticobulbar tract
- cross over
- hypoglossal nucleus = lower motor neuron
- hypoglossal nerve
- hypoglossal canal
- branches to intrinsic and extrinsic muscles of tongue (except palatoglossus CN10)
The somatomotor pathway of CN12 goes to what muscles?
intrinsic and extrinsic muscles of tongue, except for palatoglossus