Autonomics of Head, Neck, and Bladder

Question 1

Where/how do sympathetics originate?

Answer 1

descending signals from hypothalamus and medulla –> preganglionic S fibers in intermediolateral cell column (T1-T3)

Question 2

Where are sympathetic fibers located in the spinal cord?

Answer 2

intermediolateral cell column

T1-L2 (thru T3 for head and neck)

Question 3

What part of the medulla controls the sympathetic baroreceptor reflex?

Answer 3

rostral ventrolateral medulla

Question 4

What part of the brain controls skin vasoconstriction and responses to cold?

Answer 4

sympathetics

medullary raphe

Question 5

What part of the brain controls sympathetic response to stress?

Answer 5

paraventricular nucleus

lateral hypothalamus

Question 6

What is the major ganglion for Sym distribution in head?

Answer 6

Supeiror cervical ganglion

C4

Question 7

What cranial nerves and nuclei do parasympathetics travel in?

Answer 7

Edinger Westphal (midbrain) –> CN 3

Superior salivatory nucleus (pons) –> CN 7

Inf salivatory nucleus (medulla) –> CN 9

Dorsal nucleus of vagus N (Medulla) –> CN 10

Question 8

What ganglia do the facial nerve synapse at?

Answer 8

sphenopalatine ganglion –> lacrimal gland

submandibular ganglion –> submandibular and sublingual salivary glands

Question 9

What nuclei does CN 9 synapse at?

Answer 9

Otic ganglion –> parotid salivary gland

Question 10

What are the 3 causes of Horner Syndrome?

Answer 10

1. central lesion of hypothalamospinal pupillodoliater path; lateral brianstem/upper cervical SC
2. Preganglionic Lesion: damage sym chain; tumor at apex of lung
3. Postganglionic Lesion/superior cervical ganglion; compressed in int carotid A dissection, mass lesions in cavernous sinus

Question 11

How are distinctions btw pre-syn and post-syn lesions causing Horner Syndrome made?

Answer 11

pharmacologic testing of pupil

Question 12

What do you see in facial sweating in Pre and Post ganglion Horner?

Answer 12

central/pre: anhidrosis

Post: normal (except for above eyebrow)

Question 13

How do drugs that cause release of NE affect Pre and post ganglionic Horner S?

Answer 13

Central/Pre: get pupil dilation

Post: no pupil dilation (this nerve is damaged, so even adding NE won’t help)

Question 14

How do drugs that are direct alpha-agonists (solution of NE) affect central/pre and post ganglionic Horners?

Answer 14

Central/Pre: no pupil dilation

Post: exaggerated dilation

Question 15

Where are baroreceptors located and what innervates them?

Answer 15

carotid sinus: CN 9

Aortic Arch: CN 10

Question 16

What do the 2 baroreceptors respond to?

Answer 16

carotid sinus: both increas and decrease in pressure

aortic arch: only increase

Question 17

What is the PS baroreceptor reflex path?

Answer 17

increase in BP –> stretch of BR –> send excitatory signals to nucleus solitarius of medulla (9 and 10) –> nucleus ambiguus

Question 18

What does the nucleus ambiguus do in PS baroreceptor reflex?

Answer 18

vagus: inhibitory signals to SA node of heart –> lowers HR

sends inh signals to Rostral ventrolateral medulla –> inh sympathetic vasomotor activity –> vasodilation –> lower BP

Question 19

What is the SNS baroreceptor reflex?

Answer 19

decreased BP –> less stretch –> baroreceptor afferents decrease –> less signal to nucleus solitarius

less vagal activity

less inh of rostral ventrolateral medulla

more SNS activity

Question 20

How does the valsalva maneuver affect the baroreceptor reflex?

Answer 20

less blood back to heart and head

Question 21

When would you do carotid massage on pts?

Answer 21

massage –> stretch –> slows HR

in pts with SVT

Question 22

What occurs in baroreflex afferent failure?

Answer 22

damage to sinus, arch, etc

fluctuating Hypertension

Question 23

What occurs in baroreflex efferent failure?

Answer 23

main consequence = orthostatic hypotension

Question 24

What prevents voiding?

Answer 24

lumbar SNS from T12-L2 –> sacral splanchnic n/hypogastric N –> relaxes detrusor m, contracts internal sphincter

Question 25

What is the voiding reflex?

Answer 25

PS from S2-S4 –> pelvic splanchnic N –> contraction of detrusor m and relaxation of internal sphincter

Question 26

What is the micturition reflex?

Answer 26

once bladder reaches ~300 ml –> afferents are sent to PAG in midbrain –> pontine micturition center

1. excitatory signals activate sacral PS nucleus
2. Inhibitory signals to Onuf nucleus

coordinated contraction of detrusor and relaxation of ext sphincter

Question 27

Where is the voluntary control center of micturition?

Answer 27

medial frontal cortex

Question 28

What does the onuf nucleus do?

Answer 28

motor axons from onuf –> somatic pudendal N –> external urethral sphincter + pelvic floor m

must be inhibited for micturition

Question 29

What are the 3 types of neurogenic bladder?

Answer 29

uninhibited

spastic

flaccid

Question 30

What is uninhibited bladder?

Answer 30

lesion in inhibitory connections in brain –> can’t inh pontine micturition center

common in elderly

urinary urgency + incontinence

bladder volume = normal

intravesical P = normal

no retention

Question 31

What is spastic bladder?

Answer 31

lesions that interrupt pontine M center + sacral spinal cord

occur in trauma or MS

micturition reflex preserved, but no pons control –> contractions of detrusor and ext sphincter not coordinated

increased intravesical pressure –> hypertrophy of bladder wall –> reduction of bladder volume

later: urinary retention

Question 32

What is flaccid bladder?

Answer 32

midline/bilateral lesions of Sacral SC/cauda equina/ conus medullaris (tumor, diabetes, slipped disc)

no micturition reflex –> distended bladder

overflow incontinence + urinary retention

anal reflex absent + perianal anesthesia