Cranial nerves 4- parasympathetics

Question 1

where are the cell bodies of the parasympathetic system found

Answer 1

brainstem
or
S2-4 spinal cord segments

Question 2

where are the cell bodies of the sympathetic system found

Answer 2

lateral horn of T1-2 spinal cord segments

Question 3

describe the sympathetic system

Answer 3

short pre-synaptic neuron
long post-synaptic neuron
EXCEPT SPLANCHNIC n

-pre neurons emerge from the cord
-they pass to the sympathetic trunk in white rami communicantes
-they synapse in a ganglion
-post fibres from grey ramus communicantes
-joins a spinal nerve in which it is distributed to the body wall

-synapses with sympathetic ganglion which are located close to the vertebral column

Question 4

what does each sympathetic trunk extend between

Answer 4

between the atlas and coccyx
trunks fuse with each other in the ganglion impar, opposite the coccyx

Question 5

where do the sympathetic ganglia fuse

Answer 5

in the cervical region
-superior (c1-4)
-middle (c5-6)
-inferior (c7-8) cervical ganglia

Question 6

what forms the stellate ganglion/cervicothoracic ganglion

Answer 6

inferior cervical and T1
(c7-t1)

Question 7

where do sympathetics that suply head and neck originate from

Answer 7

sympathetics that supply head and neck originate from T1-2

Question 8

how do sympathetics supply eye if they originate from T1-2

Answer 8

ascends in sympathetic chain to superior cervical ganglion and synapse there
post synaptic wrap around internal carotid artery and enter into cranial cavity
and join nasociliary nerve
then sympathetics join long ciliary nerve
enters eyeball
supply dilator pupilla muscle (scared–wide open pupil)
also join superior division of oculomotor nerve and supply LEVATOR PALPEBRA SUPERIORIS (eyelids open)

Question 9

what is horners syndrome

Answer 9

ptosis
miosis
anhydrosis
flushing- veins dont have sym input
no sweating (only supplied by sympathetics)

interruption of sympathetics to head due to tumour of apex of lung
invades t1 and sympathetic chain
so cant reach superior cervical ganglion
no sympathetics so parasympathetics are dominant

Question 10

where are parasympathetic ganglia found

Answer 10

close to the organ
long pre
short post

Question 11

which cranial nerves have their own parasympathetic fibres

Answer 11

3
7
9
10

Question 12

what is the nucleus of the 3rd CN and where is it found

Answer 12

in midbrain

Edinger-Westphall

Question 13

describe the routes of the parasymp of the oculomotor nerve

Answer 13

runs with motor fibres
runs anteriorly on lateral wall of cavernous sinus to superior orbital fissure
into orbit
sympathetics join superior and parasympathetic join inferior division of ophthalmic nerve
parasym fibres synapse in ciliary ganglion and synapse
postganglion fibers join short ciliary nerves (long nerves are sympathetic)
penetrate sclera and enter eyeball to ciliary muscle (accommodation) and sphincter pupilla muscle (meiosis)!!

Question 14

is ciliary ganglion para or sympathetic ganglion

Answer 14

parasympathetic

Question 15

what does the light reflex test
how to do it and the physiology behind it

Answer 15

test optic and oculomotor nerve

shine light into eye
optic nerve pick up sensation
some nerves of optic n cross into optic chiasm
optic tract has connections with pretectal area which contains pretectal nucleus
pretectal nucleus is stimulated by light
the pretectal nucleus has connections to both autonomic oculomotor nuclei
these will activate para neurons in edinger westphal on both sides-BILATERAL
these para fibers travel alongside oculomotor nerves->ciliary ganglion and synapse
post will join short ciliary nerves
constrict pupil
light shone on one eye but both eyes will constrict
DIRECT AND CONSENSUAL LIGHT REFLEX

if no constriction on other eye- problem with crossing at posterior commissure

Question 16

what happens if there is an injury to the oculomotor nerve

Answer 16

no para input for pupil constriction
-pupil dilation

loss of motor innervation to levator palpebrae superioris
-ptosis

loss of motor innervation to extraocular muscles except LR604
-eye turns downwards and outwards

Question 17

what is the para nucleus of the facial nerve called and where is it

Answer 17

superior salivatory nucleus
in pons

Question 18

what is the route of the paras fibers
what is their nucleus

Answer 18

exit brainstem w facial nerve at pontocerebellar angle
enter internal acoustic meatus
enter facial canal

n. intermedius

Question 19

what do the parasympathetic fibers of the facial nerve do

Answer 19

join great petrosal nerve
this receives sympathetics and para
both become nerve of pterygoid canal
synapse at pterygopalatine fossa (where pterygopalateine ganglion is found)
this ganglion is para- so parasympathetics synapse here, sympathetics just pass through
synapse with postganglionic neuron

join zygomatic n of maxillary division, then lacrimal n of ophthalmic and supply lacrimal gland

also supply some of salivary glands
submandibular and sublingual are supplied by facial nerve
these para fibers join chorda tympani (sensory nerve for taste)
travel with chorda tympani, separate and join lingual nerve

synapse at submandibular ganglion (paras ganglion of facial nerve)
-where paras fibers of submandibular and sublingual glands synapse

Question 20

what is the parasym nucleus of the glossopharyngeal
where is it found

Answer 20

inferior salivatory nucleus
in medulla

Question 21

what is the route of the parasympathetics of glossopharyngeal n

Answer 21

join sensory and motor fibers of glossopharyng
leave brainstem
pass through jugular foramen with vagus, accessory, internal jugular vein
join tympanic nerve
goes into middle ear cavity
tympanic plexus made of sensory fibers
join lesser petrosal nerve which goes to otic ganglion (paras ganglion of glossoph)

synapse with post, these axons supply parotid gland

Question 22

what does vagus supply
what is the nucleus and where is it

Answer 22

biggest para nerve
head (only PS), neck mainly thorax and abdo

dorsal nucleus
found in medulla

Question 23

what is the parasympathetic ganglion of the glossopharyngeal n

Answer 23

otic ganglion