Autonomics of Head, Neck, and Bladder Flashcards
Where/how do sympathetics originate?
descending signals from hypothalamus and medulla –> preganglionic S fibers in intermediolateral cell column (T1-T3)
Where are sympathetic fibers located in the spinal cord?
intermediolateral cell column
T1-L2 (thru T3 for head and neck)
What part of the medulla controls the sympathetic baroreceptor reflex?
rostral ventrolateral medulla
What part of the brain controls skin vasoconstriction and responses to cold?
sympathetics
medullary raphe
What part of the brain controls sympathetic response to stress?
paraventricular nucleus
lateral hypothalamus
What is the major ganglion for Sym distribution in head?
Supeiror cervical ganglion
C4
What cranial nerves and nuclei do parasympathetics travel in?
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
What ganglia do the facial nerve synapse at?
sphenopalatine ganglion –> lacrimal gland
submandibular ganglion –> submandibular and sublingual salivary glands
What nuclei does CN 9 synapse at?
Otic ganglion –> parotid salivary gland
What are the 3 causes of Horner Syndrome?
- central lesion of hypothalamospinal pupillodoliater path; lateral brianstem/upper cervical SC
- Preganglionic Lesion: damage sym chain; tumor at apex of lung
- Postganglionic Lesion/superior cervical ganglion; compressed in int carotid A dissection, mass lesions in cavernous sinus
How are distinctions btw pre-syn and post-syn lesions causing Horner Syndrome made?
pharmacologic testing of pupil
What do you see in facial sweating in Pre and Post ganglion Horner?
central/pre: anhidrosis
Post: normal (except for above eyebrow)
How do drugs that cause release of NE affect Pre and post ganglionic Horner S?
Central/Pre: get pupil dilation
Post: no pupil dilation (this nerve is damaged, so even adding NE won’t help)
How do drugs that are direct alpha-agonists (solution of NE) affect central/pre and post ganglionic Horners?
Central/Pre: no pupil dilation
Post: exaggerated dilation
Where are baroreceptors located and what innervates them?
carotid sinus: CN 9
Aortic Arch: CN 10
What do the 2 baroreceptors respond to?
carotid sinus: both increas and decrease in pressure
aortic arch: only increase
What is the PS baroreceptor reflex path?
increase in BP –> stretch of BR –> send excitatory signals to nucleus solitarius of medulla (9 and 10) –> nucleus ambiguus
What does the nucleus ambiguus do in PS baroreceptor reflex?
vagus: inhibitory signals to SA node of heart –> lowers HR
sends inh signals to Rostral ventrolateral medulla –> inh sympathetic vasomotor activity –> vasodilation –> lower BP
What is the SNS baroreceptor reflex?
decreased BP –> less stretch –> baroreceptor afferents decrease –> less signal to nucleus solitarius
less vagal activity
less inh of rostral ventrolateral medulla
more SNS activity
How does the valsalva maneuver affect the baroreceptor reflex?
less blood back to heart and head
When would you do carotid massage on pts?
massage –> stretch –> slows HR
in pts with SVT
What occurs in baroreflex afferent failure?
damage to sinus, arch, etc
fluctuating Hypertension
What occurs in baroreflex efferent failure?
main consequence = orthostatic hypotension
What prevents voiding?
lumbar SNS from T12-L2 –> sacral splanchnic n/hypogastric N –> relaxes detrusor m, contracts internal sphincter
