Session 6 - autonomic nervous system Flashcards
what is the autonomic nervous system a part of
it is part of the peripheral nervous system that controls smooth muscles (cardaic muscle) and glands (lacrimal and salivary)
it controls body functions that are not under conscious control
and maintains and fine tunes internal environment
has a pre ganglionic nerve- ganglion- and post ganglionic nerve
from which part of the CNS does the sympathetic nerves arise from
and where are the cell bodies located
thoracolumbar
T1-L2
cell bodies within lateral horn of grey matter of spinal cord
from which part of the CNS does the parasympathetic nerves arise from
and where are the cell bodies located
craniosacral
4CNs from brain stem and S2-S4
discrete collections of parasympathetic cell bodies in brainstem or within grey matter of sacral spinal cord
how do sympathetic fibres reach structures in the head and neck
they originate from T1-L2
superior cervical ganglion found in cervical part of sympathetic chain- this where the pre and post ganglionic fibres meet
post ganglionic fibres hitch hike on blood vessels (ICA and ECA) and opthalmic artery (division of ICA)
then join cranial nerves III occulomotor and CN Va trigeminal opthalmic
what is a pancoast tumor
a tumour involving the apex of the lung and the internal carotid artery causes atuonomic dysfunction partial ptosis constricted pupil (miosis) anhidrosis
which tissues does the sympathetics of the head and neck act on
eye (dilator pupillae) - pupil dilation
eye lid (superior tarsal muscle) - assists lid retraction
blood vessels - vasoconstriction
sweat glands - sweating
decreased secretion of lacrimal and salivary glands
which cranial nerves carry parasympathetic fibres from the brainstem
occulomotor III
facial VII
glossopharyngeal IX
vagus X
how do parafibres reach structures in the head and neck
they arise from brain stem from parasympathetic nuclei (edinger westphal) (4)
and hitch hike on to one of 4 cranial nerves (III,VII,IX,X)
they leave the cranial nerves at the ganglion(4) and join branches of the trigeminal nerve CNV
what are the names of the parasympathetic ganglion
ciliary
submandibular
pterygopalatine
otic
which tissues does the parasympathetics of the head and neck act on
eye (spincter pupillae and ciliary muscles)- constrict pupil and accommodation reflex (lens reflex) lacrimal glands- secretions mucosal glands- secretions salivary glands- secretions parotid glands- secretions
what is the path of CNIII occulomotor parasympathetics
brainstem (edinger westphal nucleus)
parasympathetic fibres emerge with CNIII fibres
hitch hikes on CN III
pre ganglionic and post ganglionic fibres meet at ciliary ganglion
post ganglionic fibres hitch hike on small branches from CNVa trigeminal opthalmic
reach the eye where they innervate the ciliary body: lens constrictor of pupil
describe the pathway involved in causing both eyes to shut when light is shone in to the left eye
light in the left pupil
sensory afferents from left retina (CNII)
some branches leave CNII to enter midbrain
connection with EDW nuclei (left and right)
parasympathetic fibres from EDW leave brainstem
hitch hike on CNIII (left and right)
pass via cililary ganglion
reach sphincter pupillae
causes direct light reflex in the left eye
and consensual light reflex in right eye
what is the path of CNVII facial parasympathetics
parasympathetic (preganglionic) nerves exit brainstem with the facial nerve
once within the petrous temporal bone the pre ganglionic parasympathetic reach their target tissue by continuing via two main branches of the facial nerve arising inside the the petrous bone (greater petrosal nerve and chorda tympani nerve)
parasympathetic associated with CNVII have two associated parasympathetic ganglia (pterygopalatine and submandibular ganglion)
path of greater petrosal parasympatheics
greater pertrosal
pteryogopalatine ganglion
lacrimal gland
nasal and oral mucosal glands
path of greater chorda tympani
chorda tymani
submanidbular ganglion
submandibular, sublingual salivary glands
