6. Autonomic Innervation Of Head And Neck Flashcards
What is the autonomic nervous system part of?
Peripheral nervous system
Where is the central control of the autonomic nervous system from?
Hypothalamus
What does the autonomic nervous system maintain?
Maintains and fine tunes internal environment
What makes up the autonomic nervous system?
Sympathetic and parasympathetic nervous systems
What are the target tissues of ANS?
Smooth muscle
Cardiac muscle
Glands (lacrimal, mucosal, salivary)
What does sympathetic nervous system do?
Smooth muscle of blood vessels, eye lid and iris (dilator pupillae)
Sweat glands
Arrector pili muscles
Decreases secretions from salivary and lacrimal glands
What does the parasympathetic nervous system do?
Smooth muscle of iris (sphincter pupillae) and muscle in ciliary body (controls thickness of lens)
Lacrimal glands
Salivary and mucosal glands
Smooth muscle of respiratory and GI
What is the thoracolumbar outflow?
Sympathetic exits of CNS
Segments T1-L2 of spinal cord
Cells bodies within lateral horn of grey matter of spinal cord
What is the craniosacral outflow?
Exit of parasympathetic from CNS
Cranial - 4 cranial nerves
Sacral - S2-S4 (pelvic splanchnics)
How would the pupil differ in a Horner’s syndrome compared to an oculomotor nerve lesion?
Horner’s syndrome - miosis (constricted pupil)
CNIII lesion - mydriasis (dilated pupil)
What happens in Horner’s syndrome?
Miosis
Ptosis
Anhydrosis
What causes Horner’s syndrome?
Pathology involving apex of lung and/or common carotid artery and its branches can damage the sympathetic trunk carrying the nerves that supply the eye and face, causing autonomic dysfunction
Which cranial nerves carry parasympathetic fibres from the brainstem?
Oculomotor
Facial
Glossopharyngeal
Vagus
What is the route of the parasympathetic fibres of cranial nerves?
Arise from brainstem from parasympathetic nuclei Hitch hike onto one of 4 CNs Parasympathetic ganglia Hitch hike on to branches of CNV Target tissues
What are the 4 parasympathetic nuclei?
Edinger westphal
Superior salivary
Inferior salivary
Dorsal motor
What are the 4 parasympathetic ganglia?
Ciliary
Submandibular
Pterygopalatine
Otic
What is the route of CNIII?
Brainstem (EWN)
Parasympathetic fibres emerge with CNIII fibres
Ciliary ganglion
Hitch hikes on small ganglia from CNVa
Eye - ciliary muscle, sphincter pupillae muscle
What happens when light is shone in left pupil?
- Sensory afferent from left retina (CNII)
- Some branches leave CNII to enter midbrain
- Connection with EDW nuclei (left and right)
- Pre-ganglion is parasympathetic fibres from EDW leave brainstem with CNII (left and right)
- Pre-ganglionic parasympathetic synapse in ciliary ganglion, become post-ganglionic
- Reach sphincter pupillae muscle of iris
How do parasympathetic from CNII reach target tissues?
Via 2 branches of CNVII that arise in petrous bone:
- greater petrosal nerve
- chorda tympani nerve
What are the 2 associated parasympathetic ganglia?
Pterygopalatine ganglion
Submandibular ganglion
What is the route of parasympathetic fibres of CNIX?
Arise from brainstem
Exits through jugular foramen bu at this point splits into no. of branches
Tympanic nerve which supplies sensory to middle ear
Parasympathetic fibres run with tympanic nerve initially
Then parasympathetic exit middle ear as lesser petrosal nerve
Synapses in otic ganglion (hitch hikes on branch of CNVc)
Travels to parotid gland
What is the path of the parasympathetic fibres of vagus nerve?
Exit brain stem as CNX
Pr-ganglionic parasympathetic fibres run within CNX and its branches
Meet ganglion at or in target tissue - mucosal glands in pharynx, larynx , respiratory and GI tract, smooth muscle of oesophagus, trachea, respiratory and GI tract, heart
