Lecture 10: Cranial Nerves IX, X, and XI Flashcards
What is CN IX?
Glossopharyngeal nerve
What number is the Glossopharyngeal Nerve?
IX
What part of the brainstem does the Glossopharyngeal Nerve exit?
It exits laterally on the medulla
Where does the Glossopharyngeal nerve exit the cranial vault?
The Jugular Foramen
What exits on the Jugular Foramen?
CN IX - Glossopharyngeal
CN X - Vagus
CN XI - Spinal Accessory
Venous return from the brain via dural sinus
What kind of nerve is CN IX - Glossopharyngeal Nerve?
Motor, Sensory and Parasympathetic
What is the motor function of CN IX - Glossopharyngeal nerve?
It innervates one muscle the stylopharyngeus (elevates pharynx)
What nerve innervates the Stylopharyngeus?
The motor component of the Glossopharyngeal nerve
What does the Stylopharyngeus muscle do?
Elevates the pharynx via motor innervation from CN IX
What is the nucleus in the brainstem that houses the LMN for the Stylopharyngeus?
The Nucleus Ambiguus
What mediates the elevation of the Stylopharyngeus?
The motor function of CN IX - Glossopharyngeal Nerve
What does the Nucleus Ambiguus do?
It houses the LMN for the motor function of the Glossopharyngeal Nerve
What is the nucleus connected to the motor function of the Glossopharyngeal Nerve?
The Nucleus Ambiguus
What is the general sensory function of CN IX - Glossopharyngeal Nerve?
*Sensation to the post 1/3 of the tongue
*Chemo and baroreceptors of the carotid sinus + body
What supplies sensation to the posterior 1/3 of the tongue?
CN IX - Glossopharyngeal Nerve
What is the afferent part of the gag reflex?
The sensation to the posterior 1/3 of the tongue is sensed by the hypoglossal nerve CN IX that senses when food is in the past of the tongue
What nucleus is the sensory innervation of the posterior 1/3 of the tongue sensed by?
The spinal trigeminal nucleus
What does the spinal trigeminal nucleus sense?
Pain from the any part of the trigeminal nerve (V) and sensory information from the posterior 1/3 of the tongue via CN IX (glossopharyngeal)
What nucleus does sensory information from the posterior 1/3 of the tongue sensed via CN IX (glossopharyngeal)?
The Spinal Trigeminal nucleus
What senses chemo and baroreceptors of the carotid sinus + body?
The Glossopharyngeal nerve CN IX
What is the sensory to the Vagus motor?
The Glossopharyngeal nerve
What instigates the swallowing reflex?
The feeling of food at the sensed by CN IX that feels the sensation
What CN does the motor of the swallowing in the swallowing reflex?
The vagus nerve
What is the breakdown of the sensation and taste to the tongue?
Anterior 2/3
*Taste - Facial nerve VII
*Sensation - Trigeminal V3
Posterior 1/3
*Taste - Glossopharyngeal IX
*Sensation - Glossopharyngeal IX
What nucleus in the brainstem is the sensation of baro and chemoreceptors by the Glossopharyngeal nerve CN IX associated with?
The nucleus of the solitary tract
What is the synapses at the nucleus of the solitary tract?
Taste from the facial nerve and the glossopharyngeal nerve and chemo and baroreceptors from the glossopharyngeal nerve
What do the chemo and baroreceptors associated with the Glossopharyngeal nerve sense?
BP and oxygen concentration
What is the special sensory function of the Glossopharyngeal nerve?
Taste to the posterior 1/3 of tongue
What is the nucleus associated with the taste to the posterior 1/3 of the tongue sensed by CN IX?
The Nucleus of the Solitary Tract
What is the Parasympathetic function of the Glossopharyngeal nerve CN IX?
Supplies parotid gland via the otic ganglion
What nucleus in the brainstem supplies the sympathetic function of CN IX to innervate the parotid gland?
The inferior Salivatory Nucleus
What is the inferior Salivatory Nucleus?
The nucleus in the brainstem associated with the innervation of the parotid gland by CN IX
What does damage or disease to CN IX do?
Cause difficulty in swallowing and loss of gag reflex
What is the summary of function of CN IX - Glossopharyngeal?
*Motor - innervates the stylopharyngeus
*Sensory (general) - sensation to post 1/3 of tongue and pharynx
*Sensory (special) - taste to posterior 1/3 of tongue
*Parasympathetic - Supplies parotid gland
What nuclei are associated with each function of CN IX - Glossopharyngeal?
*Motor - innervates the stylopharyngeus (Nucleus Ambiguus)
*Sensory (general) - sensation to post 1/3 of tongue and pharynx (Spinal Trigeminal Nucleus)
Chemo and baroreceptors (Nucleus of the Solitary Tract)
*Sensory (special) - taste to posterior 1/3 of tongue (Nucleus of Solitary Tract)
*Parasympathetic - Supplies parotid gland (Inferior Salivatory Nucleus)
What nucleus is the motor function of CN IX associated with?
Nucleus Ambiguus
What nucleus is the general sensory function of CN IX associated with?
*Sensation to posterior 1/3 of tongue and pharynx - Spinal Trigeminal Nucleus
*Chemo and baroreceptors - Nucleus of the solitary tract
What nucleus is the special sensory function of CN IX associated with?
Nucleus of the solitary tract
What nucleus is the Parasympathetic function of CN IX associated with?
Inferior Salivatory Nucleus
What is the one muscle in the throat innervated by the Glossopharyngeal Nerve?
The Stylopharyngeus muscle - the rest are innervated by the vagus
What innervates the salivary glands?
Facial VII and the Glossopharyngeal IX
What is the Otic ganglion?
The ganglion that parasympathetic neurons going to the Parotid gland synapse on
What nucleus would touch to the back of the throat synapse on?
The spinal trigeminal nucleus of V (along with pain of the face)
What synapses on the spinal trigeminal nucleus of V?
Sensation to the throat and pain from the face
What nerve comes off of the brainstem posteriorly?
CN IV the trochlear
Where does the vagus nerve X exit the cranial vault?
The jugular foramen
What is the efferent to the gag and swallowing reflex?
The vagus nerve X
What kind of nerve is the vagus nerve?
Motor, Sensory and Parasympathetic
What is the motor function of the Vagus nerve X?
Muscles of the soft palate, pharynx and larynx (efferent gag reflex)
What is the sensory function of the vagus nerve X?
*Sensation to soft palate, pharynx and larynx
*Baroreceptor to hollow organs - stomach and bowel
What is the parasympathetic function of the vagus nerve X?
*Motor to smooth muscle in thoracic and abdominal organs and distal part of transverse colon
*Slowing down HR
*Visceral afferents from the organs of the CNS
What nucleus is associated with the motor function of the motor function of CN X?
The Nucleus Ambiguus
What Nucleus is associated with the sensory function of the Vagus nerve?
Nucleus of the solitary tract
What nucleus is associated with the parasympathetic function of the vagus nerve X?
Dorsal Motor Nucleus of Vagus (DMNV)
How is the Nucleus ambiguus associated with the vagus nerve?
It is where UMN synapse onto LMN to innervate muscles of the soft palate, pharynx and larynx
How is the Nucleus of the solitary tract associated with the vagus nerve?
It is where sensory baroreceptors of the the hollow organs synapse for the first time
How is the Dorsal Motor Nucleus of Vagus associated with the vagus nerve?
It is where parasympathetic efferents synapse to go to abdominal organs and where visceral afferents from organs go to the CNS
What is the summary of function of the Vagus Nerve X?
*Motor - to muscle of the soft palate, pharynx and larynx
*Sensory to soft palate pharynx and larynx. Baroreceptors to hollow organs
*Parasympathetic - to smooth muscle in thoracic and abdominal organs. Slows down HR. Carries visceral afferents to CNS
What is the summary of the Nuclei of the Vagus Nerve X?
*Motor - to muscle of the soft palate, pharynx and larynx (Nucleus Ambiguus)
*Sensory to soft palate pharynx and larynx (spinal nucleus). Baroreceptors to hollow organs (Nucleus of the Solitary Tract)
*Parasympathetic - to smooth muscle in thoracic and abdominal organs. Slows down HR. Carries visceral afferents to CNS. (Dorsal Motor Nucleus of Vagus - DMNV)
Where is the parasympathetic motor cell bodies of the vagus nerve found?
In the DMNV
What happens if the parasympathetic branch of the vagus nerve is accidentally cut?
There are no deficits because the parasympathetic of the other side kicks in
What happens to the vagus nerve if it is damaged by disease?
There is difficulty in speech and swallowing
How is the Spinal Trigeminal Nucleus associated with the Vagus X nerve?
It is where sensation from the palate, pharynx and larynx synapse for the first time
What is the recurrent laryngeal nerve?
A motor branch of the vagus nerve that goes down and loops back up to innervate the larynx
How is the spinal trigeminal nucleus associated with the vagus nerve CN X?
It is where sensory afferents for the palate, pharynx and larynx synapse
Why is the recurrent laryngeal artery where it is?
It looped down underneath the right subclavian and the arch of aorta during the development
What happens if the recurrent laryngeal artery is nicked?
Part of the vocal cords are paralyzed causing hoarseness
How does the Gag reflex work?
When sensation is sensed by the glossopharyngeal nerve CN IX, it synapses in the brainstem at the spinal trigeminal nucleus and goes directly to the vagus and causes the muscles to gag
How does the Baroreceptors and Chemoreceptors in the common carotid work?
Sensory information from the baro or chemoreceptors is sensed by the glossopharyngeal nerve and sent to the NTS where it synapses and goes directly to the vagus nerve which decreases or increases HR
What cervical vertebrae does the spinal accessory come from?
C2 - C5
What muscles does the spinal accessory nerve innervate?
Sternocleidomastoid and the Trapezius