Autonomic NS Flashcards
Where is the central control of the autonomic NS?
Hypothalamus
Describe the autonomic NS
Peripheral NS Controls SM and glands Involuntary control Maintains and fine tunes internal environment Sequential 2 neurone arrangement
From which region does the SNS come?
Thoracolumbar
T1-L2
From which region does the PNS come?
Brainstem (III, VII, IX and X) and sacral outflow (S2-4)
What are the action of SNS in the head and neck?
Constricts SM of blood vessels Retracts tarsal muscle of eyelid Dilates pupil - dilator pupillae Sweating Errector pilli muscles Decreased salivary and lacrimal gland secretions
What are the PNS actions in the head and neck?
Constriction of pupil - sphincter pupillae
Ciliary body movement - controls thickness of lens
Stimulates lacrimal, salivary and mucosal glands
Where does the majority of SNS to HN come from?
T1 and T2
Describe the pathways of SNS to the HN
Preganglionic neurones enter sympathetic chain
Ascend to synapse at cervical ganglia of chain
Postganglionic neurones hitchhike on blood vessels (mostly internal and external carotid arteries)
What happens when SNS fibres reach the eye?
Fibres to the eyelid hitchhike on oculomotor nerve
Fibres to pupil hitchhike on trigeminal nerve
What is a Pancoast tumour?
Tumour of the apex of the lung
Can interrupt the sympathetic chain
Describe the clinical syndrome when the sympathetic chain is disrupted
Horner’s syndrome
Miosis (pupil constriction)
Partial ptosis (eyelid droop)
+/- anhydrosis
Which cranial nerves carry PNS?
III, VII, IX and X
Oculomotor, facial, glossopharyngeal and vagus
Describe the course of the PNS to HN
Leaves brainstem from PNS nuclei
Hitchhike on branch of either III, VII, IX or X
Post-ganglionic neurones hitchhike on branches of the trigeminal (V) - except the vagus
What are the PNS ganglia of the HN and which CNs supply them?
Ciliary - III
Pterygopalatine - VII
Submandibular - VII
Otic - IX
What are the actions of the PNS after the ciliary ganglion?
Sphincter pupillae
Ciliary body
