PNS 7 Flashcards
What CN arises from the medulla between the OLIVE (where CN XII arises) and the Inferior Cerebellar Peduncle?
CN IX - GLOSSOPHARYNGEAL NERVE
Through what Foramen does CN IX - the GLOSSOPHARYNGEAL NERVE exit the skull?
The JUGULAR FORAMEN
What 5 (!) functional fiber types of the Glossopharyngeal are there? Describe each briefly
- GSA - from mucosa of the Tympanic Cavity, Auditory Tube, Posterior Tongue, Oropharynx, Fauces & Soft Palate; Additionally some Skin of the Auricle
- SVA - Mediates taste from the POSTERIOR 1/3 of the TONGUE
- GVA - From carotid body Chemoreceptors & Baroreceptors
- GVE - to the OTIC GANGLION
- SVE - to the lone muscle derived from the 3rd Pharyngeal Arch
What 2 ganglia do ALL of the sensory neurons (GSA, GVA, SVA) of CN IX have their cell bodies located in? Where are these ganglia found?
The SUPERIOR & INFERIOR Ganglia of the glossopharyngeal nerve. Superior is located just above the jugular foramen (in posterior cranial fossa) & the Inferior is located just below the jugular foramen.
The central processes of what 2 pseudounipolar sensory neurons project to the SOLITARY NUCLEUS (in the CNS) from the inferior & superior ganglia of CN IX?
- SVA fiber project to the Rostral part of the Solitary Nucleus
- GVA fibers project to the Caudal part of the Solitary Nucleus
CN IX GSA fibers project from the inferior & superior ganglion to what CNS nucleus?
Glossopharyngeal GSA fibers project to the SPINAL TRIGEMINAL NUCLEUS.
CN IX Efferent lower motor SVE neuron cell bodies are found in the Nucleus in the Medulla?
The NUCLEUS AMBIGUOUS
CN IX Efferent Preganglionic Parasympathetic Neurons (GVE) are located in what nucleus w/in the Medulla?
The INFERIOR SALIVATORY NUCLEUS
Immediately after exiting the skull CN IX gives off what branch that will then immediately re-enter teh skull?
The TYMPANIC NERVE
Through what opening does the Tympanic Nerve re-enter the temporal bone through (after CN IX left the jugular foramen)?
TYMPANIC CANALICULUS
After exiting the Tympanic Canaliculus the Tympanic Nerve ramifies (branches) to form what? Where?
Tympanic Nerve ramifies in the TYMPANIC CAVITY to form the TYMPANIC PLEXUS
AFFERENT branches of the Tympanic Plexus innervate mucosa linings of what 3 things?
- TYMPANIC CAVITY
- AUDITORY TUBE
- MASTOID AIR CELLS
What EFFERENT branch of the Tympanic Plexus carries Preganglionic Parasympathetic fibers (GVE) to the OTIC GANGLION?
the LESSER PETROSAL NERVE
From the Otic Ganglion, where do the Postganglionic Parasympathetics travel?
The Parotid Gland, where they induce salivation upon perception of food.
Frey’s Syndrome is a condition where a person perspires every time they see/think about food. Why might this happen?
B/c the postganglionic parsympathetics from the otic ganglion, that usually causing salivation in the PAROTID GLAND, join briefly with the AURICULO-TEMPORAL Nerve of CN V3. If following surgery/accidental lesion of this section of nerve there is cross wiring the otic ganglion parasympathetics will cause sweating upon the perception of food instead of salivation.
As the Glossopharyngeal Nerve crosses the Internal Carotid Artery laterally what branch containing GVA fibers arises?
The CAROTID SINUS NERVE
The CN IX branch, the Carotid Sinus Nerve, contains GVA fibers from what 2 receptors?
- BARORECEPTORS in the Carotid SINUS; &
2. CHEMORECEPTORS in the Carotid BODY
Branches from what 2 cranial nerves unite near the Middle Pharyngeal Constrictor to form the PHARYNGEAL PLEXUS?
- PHARYNGEAL BRANCHES of the Glossopharyngeal - CN IX
2. Vagus Nerve Branches - CN X
PHARYNGEAL BRANCHES from CN IX supply sensory fibers to mucosa located where? What do they mediate there?
CN IX Pharyngeal Branches supply sensory fibers to OROPHARYNGEAL MUCOSA & mediate the AFFERENT LIMB of the GAG REFLEX
Testing the GAG REFLEX is the ONLY reliable way to test the integrity of what cranial nerve? What does stimulation of the gag reflex induce?
Cranial Nerve IX - Glossopharyngeal Nerve
-Elevation of the Soft Palate & Pharyngeal Constriction
CN IX gives off a small motor branch that innervates the ONLY muscle derived from the 3rd Pharyngeal Arch. What type of Nerve Fibers does this branch contain? What is the name of the nerve and muscle?
- The MUSCULAR BRANCH of CN IX goes to the STYLOPHARYNGEUS MUSCLE.
- This nerve is also called the Stylopharyngeus Nerve. It contains SVE fibers
How does the Stylopharyngeus muscle help the Glossopharyngeal muscle get to its next location?
Both CN IX & the Stylopharyngeus muscle curve forward and enter the PHARYNX together b/t the Superior & Middle Pharyngeal Constrictors
In the Pharynx the glossopharyngeal nerve splits into what 2 branches?
- TONSILAR Branch of CN IX
2. LINGUAL Branch of CN IX
The Tonsilar Branch of CN IX innervates what 3 structures? What is the Nerve functional type?
The Tonsilar Branch contains GSA fibers & innervates…
- The PALATINE TONSIL
- The FAUCES (palatoglossal & palatopharyngeal arches) that surround the palatine tonsil
- The SOFT PALATE (superior to palatine tonsils)
The Lingual Branch of CN IX innervates what?
Posterior 1/3 of the tongue
What 2 nerve fiber types does the Lingual Branch contain? What information does each transmit FROM the posterior 1/3 of the tongue?
- General sensation is transmitted from the tongue by GSA fibers
- Gustatory (taste) sensation is transmitted from the tongue by SVA fibers
Like CN IX the VAGUS (CN X) leaves the MEDULLA from what sulcus by multiple roots?
The POSTOLIVARY SULCUS
The roots of CN X join with fibers from the Cranial Root of what cranial nerve? Hint: This CN arises from nucleus ambiguous at the Jugular Foramen
CN XI - ACCESSORY Nerve
What are the 5 functional components of CN X? Briefly describe each
- SVE: to the 4th & 6th arch skeletal muscles of the larynx, pharynx, palate & upper esophagus
- GVE: Laryngeal & Pharyngeal Mucosa, esophagus, heart, pulmonary system & upper GI muscles & glands (=Neck, thorax, & abdomen! Why vagus ~ ‘the wanderer’)
- SVA: TASTE from epiglottis & Valleculae
- GSA: From Auricle, mastoid region, PCF meninges, EAM, larynx & pharynx
- GVA: from Visceroreceptors fo larynx, pharynx, heart, esophagus, GI tract, trachea, bronchi, lungs; also aortic arch receptors.
SVE fibers of the Vagus Nerve arise from what CNS nucleus?
NUCLEUS AMBIGUOUS
GVE fibers of the Vagus Nerve arise from what CNS nucleus?
DORSAL VAGAL NUCLEUS
The SUPERIOR (JUGULAR) Ganglion and the INFERIOR (NODOSE) Ganglion of the Vagus Nerve are both exclusively Sensory ganglia. Which is concerned with Somatic sensation & which is concerned with Visceral sensation?
The Superior (jugular) ganglia = SOMATIC SENSATION The Inferior (nodose) ganglia = VISCERAL SENSATION
The Vagus Nerve’s SVE fibers innervates what?
Pharyngeal & Laryngeal Musculature from the 4th & 6th pharyngeal arches
What are the 3 main branches of CN X that distribute SVE fibers?
- Pharyngeal Nerve
- SUPERIOR LARYNGEAL
- RECURRENT (inferior) LARYNGEAL
The PHARYNGEAL NERVE of CN X has SVE fibers that innervate most of what musculature? What are the 2 exceptions?
The Pharyngeal Nerve (CN X) innervates most PHARYNGEAL & PALATAL Musculature. Except…
- STYLOPHARYNGEUS (3rd pahryngeal arch derivative) in Pharynx - CN IX
- TENSOR VELI PALATINE - CN V3
Unilateral Vagal Lesions commonly result in what 2 phenomenon? Describe briefly
- ABNORMAL GAG; Posterior pharyngeal wall will deviate to the side opposite of the lesion.
- DYSPHAGIA (difficulty swallowing); when constrictor muscles are affected will have difficulty swallowing. May also lead to nasally speech and nasal reflux of fluids
What is the ONLY branch of the Superior Laryngeal Nerve that innervates laryngeal musculature?
The EXTERNAL BRANCH distributes SVE fibers
The EXTERNAL BRANCH of the Superior Laryngeal mainly innervates one muscle, what is it? It also sends a few twigs to what group of muscles in the pharynx?
- The main muscle the External Branch innervates is the CRICOTHYROID MUSCLE while sending a few SVE twigs to the INFERIOR CONSTRICTOR MUSCLES
If the External branch of the superior laryngeal is cut, what happens?
An individual will lose the ability to create pitch b/c they will not have the use of their Cricothyroid Muscles
The RECURRENT LARYNGEAL NERVES innervate most of what muscle group? What is the 1 exception?
The recurrent laryngeal nerves innervate all INTRINSIC LARYNGEAL MUSCLES except for the Cricothyroid muscles which are innervated by the External branch of Superior Laryngeal
Injury to either recurrent laryngeal nerve will result in what?
Ipsilateral paresis or paralysis of the intrinsic laryngeals leading to rough, raspy hoarseness and a less mobile vocal cord
The Meningeal Branch of CN X carries what fiber type?
GSA fibers
The meningeal Branch of CN X provides sensory information from where?
The Meningeal branch innervates the MENINGES in the Posterior Cranial Fossa
The AURICULAR BRANCH of CN X carries what fiber type?
GSA fibers
The AURICULAR BRANCH of CN X provides sensory innervation to where?
Some of the AURICLE (external ear) & CUTANEOUS Innervation of skin of the AUDITORY CANAL
What opening transmits the Auricular Branch of CN X laterally to the eat?
MASTOID CANALICULUS
After traveling through the Mastoid Canaliculus, the Auricular Branch of CN X emerges fro the temporal bone through what fissure?
TYMPANOMASTOID FISSURE - fissure b/t the tympanic cavity and Mastoid process
What is the ONLY branch of the Vagus to provide Cutaneous Innervation?
The Auricular Branch - provides cutaneous innervation of the skin in the Auditory Canal
Why would cutaneous stimulation of the Auditory Canal possibly cause one to cough?
Stimulation of the auditory canal would activate the Auricular branch of the Vagus. The Vagus also has sensory receptors w/in the pharynx - INTERNAL BRANCH of the Superior Laryngeal, which innervates the afferent limb of the cough reflex.
The INTERNAL BRANCH of the Superior Laryngeal pierces and enters the LARYNX to innervate what structure in the LARYNX?
Innervates MUCOSA of the SUPRAGLOTTIC LARYNX.
Note: Also innervates mucosa linings of the Valleculae and Piriform Recesses
Innervation of the mucosa of the supraglottic larynx by the Internal Laryngeal mediates what?
AFFERENT LIMB of the COUGH RELEX
What 2 fiber types does the Internal Branch of the superior laryngeal nerve contain?
GSA & SVA fibers
What CN is responsible for the sensory innervation of the LARYNGOPHARYNX? Both Efferent & Afferent
The VAGUS NERVE - CN X
SVA fibers mediate taste sensation from the EPIGLOTTIS and VALLECULAE (Oropharynx) via what nerve?
The INTERNAL LARYNGEAL Nerve of CN X origin.
Internal Laryngeal SVA fibers, convey taste sensation from the Epiglottis and Valleculae to what CNS nucleus?
The SOLITARY NUCLEUS. Note: the Solitary Nucleus is also known as the GUSTATORY Nucleus b/c receives taste SVAs
Vagus GVA fibers that tag along with Vagus Parasympathetics convey physiologic sensations arising from what 2 receptors?
- Mechanoreceptors responding to distension in GI tract & bladder
- Chemoreceptors respond to chemical changes in blood and stomach
In order to reach the thorax and abdomen, CN X courses through the deep neck w/in what sheath?
CAROTID SHEATH
As the Vagus approaches the mediastinum it gives rise to GVE branches to what 2 Plexuses?
- CARDIAC BRANCH to Cardiac Plexus
2. PULMONARY BRANCH to Pulmonary Plexus
What is the job of the CN X Pulmonary branch within the Pulmonary Plexus?
The GVE parasympathetics facilitate contraction of smooth muscle which constricts the Bronchial tubes.
Where are the SUPERFICIAL and DEEP Cardiac Plexuses located?
- Superficial Cardiac Plexus: Underside of the aortic arch
2. Deep Cardiac Plexus: On the Tracheal Bifurcation
Preganglionc vagal cardiac fibers synapse in small ganglia along the coronary arteries. The GVE parasympathetic inputs to the Cardiac Plexus result in what 3 things?
- Deceleration of heart beat
- Reduction in strength of myocardial contraction
- Vasoconstriction of coronary arteries
