ANS of Head and Neck Flashcards
What is function of the nasal, palatine, submandibular, sublingual, and parotid glands?
Secrete mucus into nasal and oral cavities. Function to maintain moisture i nasal and oral cavities
What is the function of mucus glands in the larynx?
Maintain moisture in airways
What is the function of smooth muscle in cerebral blood vessels?
Control blood flow and oxygenation to brain, except those in brain tissue (i.e. parenchyma)
What is the ANS route to the ciliary body + sphincter pupillae? (PANS only)
Nucleus: Edinger-Westphal (midbrain)
Preganglionic axon: CN3
Ganglion: Ciliary ganglion
Postganglionic axon: short ciliary nerves, pierce sclera and travel to muscles through perichoroidal space
What is the PANS function for ciliary body + sphincter pupillae?
Ciliary body: Allows accommodation
Sphincter pupillae: Allow miosis (pupillary construction)
What is the ANS route to the pupillary dilator muscle + superior tarsal muscle? (SANS only)
Nucleus: Intermediolateral cell column T1-2
Preganglionic axon: WCR, ascends sympathetic trunk
Ganglion: Superior cervical ganglion (SCG)
Postganglionic axon: follows blood vessels and then long ciliary nerves, pierce sclera, perichoroidal space
What is mydriasis?
Dilation of pupil, as by SANS activation for pupillary dilator
What causes partial ptosis?
Lesioning of SANS fibers to superior tarsal muscle which maintains the tonus of upper eyelid.
What does unilateral ANS lesion to CN3 cause?
PANS for pupillary constrictor + ciliary muscle Ipsilateral mydriasis (dilation of pupil due to lost constriction) Ipsilateral of accommodation reflex Loss of DIRECT light reflex (ipsilateral pupil wont constrict)
What is Horner’s syndrome? Symptoms?
Lesion of central SANS pathways or superior cervical ganglion, to eye.
- Miosis - pupil constricts
- Partial ptosis - tarsal muscle no longer functions
- Dry skin - anhydrosis
- Flushed / reddened skin from vasodilation because of lack of SANS control
What is a syndrome?
Constellation of signs / symptoms resulting from same lesion
What is the ANS route to the lacrimal, nasal, oral, and minor salivary glands? (PANS only) What is their function?
Nucleus: Superior salivatory nucleus (caudal pons)
Preganglionic axons: CN7, form greater petrosal nerve, join nerve of pterygoid canal
Ganglion: PT ganglion
Postganglionic axons: branches of maxillary and zygomatic nerves, as well as lacrimal nerve (V1) for lacrimal gland
Function: Increase tearing + mucus production
When would CN7 lesion affect PANS targets vs not?
Lesion that is proximal to the greater petrosal branching off CN7 will affect PANS (i.e. lacrimal gland) (proximal to external geniculate ganglion / external genu)
Lesion that is distal (in the external genu) to the greater petrosal branching will not affect PANS
What is the PANS route to the submandibular and sublingual glands?
Nucleus: Superior salivatory nucleus (caudal pons)
Preganglionic axons: CN7, then chorda tympani, then lingual nerve (V3)
Ganglion: Submandibular ganglion
Postganglionic axons: innervate nearby sublingual + submandibular glands
What is the PANS function to the submandibular / sublingual glands?
Increases saliva secretion from salivary glands, and increase blood flow within the glands. Glands have greater metabolic demand.
Occurs in response to food in mouth, or olfactory stimulation
What is the PANS route to the parotid gland?
Nucleus: Inferior salivatory nucleus (rostral medulla)
Preganglionic axons: Tympanic branch of CN9, branches to lesser petrosal nerve
Ganglion: Otic ganglion
Postganglionic axons: Auriculotemporal (V3) to parotid gland
What is the PANS function to the parotid gland?
Increased salivary secretion and blood flow to the gland. Starts with putting food in your mouth
What is the SANS route for all head and neck salivary glands?
Nucleus: Intermediolateral cell column T1-2
Preganglionic axons: WCR thru sympathetic trunk
Ganglion: Superior cervical ganglion
Postganglionic axons: Follow carotid plexuses (around all carotid arteries) to reach their targets
What is the SANS function to all head and neck salivary glands?
cessation of secretion and decreased blood flow to glands (i.e. parotid, submandibular, sublingual)
Can be inhibitory to PANS, makes mouth dry
What does unilateral intracranial CN7 lesion cause (proximal to greater petrosal nerve and stylomastoid foramen)?
Ipsilateral dry eye (no lacrimal gland) - cornea is prone to ulcerations
Decreased salivary secretion (submandibular + sublingual glands affected, not parotid)
Possible crocodile tears
What are crocodile tears?
When regenerating PANS fibers are aberrantly diverted to lacrimal gland, producing tearing when eating
What is Frey’s syndrome?
Possible symptoms from regenerating PANS fibers after traumatic wound to parotid gland. PANS fibers may be diverted to sweat glands overlying the skin. Salivation stimulus will produce swearing from a patch of skin over the gland
What is the ANS route to the head and neck blood vessels? (SANS only)
Nucleus: Intermediolateral cell column T1-3
Preganglionic axons: WCR thru sympathetic trunk
Ganglion: Superior cervical ganglion or stellate ganglia
Postganglionic axons: Follow smooth muscle around major arterial branches, including those on brain surfaces (conducting vessels)
What are conducting vessels vs parenchymal vessels? How does this relate to ANS?
Conducting vessels are those arteries on brain surfaces
Parenchymal vessels which penetrate the brain tissue lose ANS innervation. They are locally controlled and under control of cerebral autoregulation at the level of the blood vessel wall
