20. Autonomics of H&N

Question 1

Distribution of Symp fibers vs. Parasymp fibers to the body

Answer 1

Symp: all vascularized portions of body, PLUS sweat glands

Parasymp: restricted to H&N, body cavities, external genitalia, glandular secretion (except sweat)

Question 2

Target organs in H+N for symps and parasymps

Answer 2

Symps: vascular smooth muscle, sweat glands, arrector pili m. (hair), dilator pupillae (opens pupil), superior tarsal muscle (raises eyelid)

Parasymp: mucosal glands, salivary glands, LACRIMAL gland, sphincter pupillae (constricts pupil), ciliary m. (changes lens shape)

Question 3

What are the effects of autonomics (parasymp and symp) on the glands

Answer 3

Salivary + Lacrimal: parasymps cause more watery secretions, symps cause more viscous secretions (dry mouth)

Mucosal: Parasymps cause more viscous secretions, symps cause more watery secretions (runny nose)

Question 4

How do sympathetics travel to the head?
What are the functions of postganglionic symps?

What is Horner’s Syndrome?

Answer 4

Preganglionic - leave thoracolumbar ventral roots and synapse to superior cervical ganglion
Postganglionic - follow branches of carotid (int and ext) and vertebral arteries to their targets

Fx: regulate bloodflow, sweating, eyelid elevation (sup tarsus m.), pupil dilation (dilator pupillae)

Horner’s: damage/compression to symp trunk = ptosis and pupil constriction

Question 5

Name the 4 parasympathetic ganglia in the head - and the CNs that supply each one

What are the nerve components found in each ganglion?

Answer 5

Ciliary - CN 3
Otic - CN 9
Pterygopalatine - CN 7
Submandibular - CN 7

1. Post-sympathetic fibers
2. Pre + Post-parasympathetic fibers
3. General sensory fibers (CN V)

Question 6

Ciliary Ganglion

Pre-ganglion fiber, post-ganglion fiber, targets

Answer 6

Pre: CN 3
Post: short ciliary nerves (V1)
Target: sphincter pupillae and ciliary m.
(DOES NOT TARGET LACRIMAL GLAND)

Question 7

Otic Ganglion

Pre-ganglion fiber, post-ganglion fiber, targets

Answer 7

Pre: CN 9 - (jugular canal) - tympanic n. (pretrematic) reenters skull (tympanic canal) - [middle ear cavity] - lesser petrosal n. - (foramen ovale) - otic ganglion
Post: Auriculotemporal n. (V3) - splits around middle menangial
Target: Parotid Gland (secretomotor)

Question 8

Frey’s Syndrome

what is it, cause, physiology, tx

Answer 8

Gustatory Sweating - sweating while salivating/eating
Cause: trauma to parotid gland = regenerating parasymps make atypical connections to sweat glands - now costimulated
Physio: both symp/parasymp fibers in parotid use ACh NT, which enables this crossover
Tx: Neurectomy, anti-perspirants, BOTOX

Question 9

Crocodile Tear Syndrome

what it is, cause

Answer 9

Crying stimulated by eating
cause: Abnormal connections between greater and lesser petrosal nerves (CN 7 and CN 9) - salivation triggers lacrimal gland and parotid gland!

Question 10

Pterygopalatine Ganglion

Pre-ganglion fiber, Post-ganglion fiber, target

Answer 10

Pre: CN 7 - Greater Petrosal Nerve (across foramen lacerum) - joins deep petrosal n. (symp fibers, BEFORE GANGLION) - enters pterygoid canal (below foramen rotundum) to PPF to ganglion
Post: V2 branches to nasal mucosal glands; Zygomatic V2 n. - Lacrimal V2 n. - LACRIMAL GLANDS (all secretomotor)

Question 11

Submandibular Ganglion

Pre-ganglion fiber, Post-ganglion fiber, target

Answer 11

Pre: CN 7 - Chorda Tympani - thru infratemporal fossa and joins Lingual nerve (BEFORE GANGLION) - then synapse on ganglion
Post: re-enter lingual nerve
target: submandibular and sublingual glands and minor salivary glands (secretomotor)

Question 12

What are the three branches of the facial nerve?

Answer 12

1. Greater Petrosal (joins Deep Petrosal)
2. Chorda Tympani (to Lingual Nerve)
3. Facial Nerve Proper (out stylomastoid foramen)