Autonomic Innervation Flashcards
What is a nucleus?
What is a ganglion?
Nucleus - collection of cell bodies within the CNS
Ganglion - collection of cell bodies outside of the CNS
Why is parasympathetic outflow termed ‘craniosacral’?
Parasympathetic innervation stems from four of the cranial nerves and from the S2-S4 pelvic splanchnics
Why is sympathetic outflow termed ‘thoracolumbar’?
Outflow comes from the T1-L2 spinal cord segments
Describe the pathway sympathetic innervation to the head and neck takes
Hypothalamus - spinal cord - cell body of 2nd order neurone at the lateral horn (T1/2) - Exits spinal cord - ascends sympathetic chain - synapses to 3rd order neurone at the superior cervical ganglion - runs with branches of common carotid artery to target tissues.
The internal carotid artery carries sympathetic innervation to which target tissues?
Dilator pupillae,
Levator palpabrae superioris (note this is also innervated by cranial nerve III).
The external carotid artery carries sympathetic fibres to which target tissues?
Sweat glands of the face and neck.
What sort of injuries can disrupt sympathetic innervation to the head and neck?
Carotid artery dissection, cancer of the apical lung.
What three features are associated with Horners syndrome?
Partial ptosis (drooping of the eye),
Miosis (contracted pupil),
Anhydrosis (lack of sweating).
Why is ptosis only partial in horners syndrome?
Levator palpabrae superioris is mainly innervated by the occulomotor nerve and as such only the smooth muscle fibres are lost in horners syndrome.
What signs differentiate Horners syndrome from a CNIII lesion?
In CNIII lesion:
Pupil is dilated not constricted,
Eye assumes down and out position.
Which cranial nerves carry parasympathetic fibres from the brainstem?
Occulomotor (III),
Facial (VII),
Glossopharyngeal (IX),
Vagus (X).
Describe the route of parasympathetic innervation to the head and neck
Arise via brainstem from parasympathetic nuclei - run with one of the 4 cranial nerves - synapse with parasympathetic ganglia - join distal branches of CN V.
Which parasympathetic nucleus is associated with the occulomotor nerve?
Which parasympathetic ganglion?
Endinger Westphal nucleus,
Ciliary ganglion.
Which two parasympathetic ganglions synapse with the facial nerve?
What do they innervate?
Pterygopalatine - lacrimal glands
Mandibular - salivary glands (bar parotid) and nasal mucosal glands
Which intrapetrous branch of the facial nerve is the pterygopalatine ganglion associated with?
Greater petrosal nerve
Which branch of the facial nerve is the submandibular parasympathetic ganglion associated with?
Chorda tympani nerve
Which parasympathetic ganglion is associated with the Glossopharyngeal nerve?
What does it supply?
Otic ganglion
Parotid gland
What structures does the vagus nerve carry fibres from the dorsal motor nuclei to?
Mucosal glands and smooth muscle of the larynx, respiratory tract and GI tract,
The heart.
What are the four parasympathetic ganglia?
Ciliary - occulomotor
Pterygopalatine - facial
Submandibular - facial
Otic - Glossopharyngeal
What is the direct pupillary light reflex?
What is the consensual pupillary light reflex?
Direct - bright light stimulates constriction of the pupil in the ipsilateral eye
Consensual- bright light stimulates constriction of the pupil of the contralateral eye
