Cervical Autonomic Nervous System Flashcards
Are autonomic pathways afferent or efferent?
Efferent
What is the difference between afferent and efferent?
Afferent - travels from periphery to CNS
Efferent - travels from CNS to periphery
How do neurones synapse in autonomic pathways
2 neurones which synapse at a ganglion
Preganglionic and postganglionic
Which neurones in autonomic pathways are myelinated?
Preganglionic neurones are myelinated, postganglionic are not
What neurotransmitters are used for communication in the ANS?
Acetylcholine
Noradrenaline
What are acetylcholine and noradrenaline releasing fibres known as?
Acetylcholine releasing - cholinergic
Noradrenaline releasing - adrenergic
What is a ganglion?
A collection of nerve cell bodies within the PNS
Where are preganglionic neurones found in the PS NS and where do they travel?
Craniosacral:
Cranial nerves III, IV, IX and X
Spinal segments S2 - S4
Travel to ganglia located close to target organ
Where are preganglionic neurones found in the sympathetic NS and where do they travel?
Thoracolumbar - Spinal segments T1 - L2 specifically in the lateral horn
Travel to paravertebral and prevertebral ganglia close to CNS
How is the sympathetic chain formed?
Paravertebral ganglia extend from the base of the skull to the coccyx where the left and right chains join at the ganglion impar
What forms the stellate (star shaped) ganglion?
The fusion of the C7 and T1 ganglia
How do all preganglionic sympathetic neurons first travel?
They leave the spinal cord through the ventral root
Form part of a spinal nerve
Enter the ganglia of the sympathetic chain via the white ramus communicans
Which different routes can preganglionic sympathetic neurones take?
- Synapse in the ganglia at the same level with a postganglionic neuron that exits through the grey ramus communicans
- Travel up or down the chain to synapse in a ganglion at a different level with a postganglionic neurone that exits through the grey ramus communicans
- Exit the ganglia via a splanchnic nerve to a prevertebral ganglion where it will synapse with a postganglionic neurone
What are the cervical ganglia and where are they found?
Superior cervical ganglion at C1/C2
Middle cervical ganglion at C6
Inferior cervical ganglion at C7
The superior cervical ganglion supplies its branches via what?
ICA and ECA (forming plexuses)
Cervical spinal nerves (C1-C4, cervical plexus)
Pharynx
Superior cardiac nerves
The middle cervical ganglion supplies its branches via what?
Cervical spinal nerves (C5, 6)
Middle cardiac nerves
The inferior cervical ganglion supplies its branches via what?
Vertebral artery (forming a plexus)
Cervical spinal nerves (C7 - T1;C7 and C8 to brachial plexus)
Inferior cardiac nerves
What do the cervical ganglia regulate sympathetic innervation of?
Eyes (pupil dilation)
Eyelids
Lacrimal glands
Carotid body
Salivary glands
Sweat glands
What is Horner’s syndrome?
Damage to cervical sympathetic trunk resulting in the absence of sympathetically stimulated functions on ipsilateral side of head
What are the possible effects of Horner’s syndrome?
Constriction of pupils (miosis)
Drooping of superior eyelid (ptosis)
Vasodilation and absence of sweating on face/neck (flushed face and anhydrosis)
Where do splanchnic nerves synapse?
With postganglionic neurones in prevertebral ganglia
Ventral to the aorta and named based on the vessels they lie near to:
Celiac
Superior mesenteric
Inferior mesenteric ganglia
Describe the adrenal medulla
(Suprarenal gland) located superior to the kidney
Has an outer cortex and an inner medulla
What supplies the adrenal medulla and how do these nerves synapse?
Sympathetic preganglionic neurones
These synapse with Chromaffin cells in the adrenal medulla that release adrenaline (80%) and noradrenaline (20%) into the bloodstream
Describe the path of pre and postganglionic CN III neurones in the PS nervous system
Preganglionic neurones travel from Edinger-Westphal nucleus in the brainstem to the ciliary ganglion
Postganglionic neurones travel to innervate the ciliary muscle and sphincter pupillae (controls pupil)]
Describe the pathway of CN VII in the PS nervous system
Sup salvatory nucleus in the brain stem to pterygopalatine ganglion and submandibular ganglion
Pterygopalatine ganglion to the lacrimal gland and nasal mucosa (via greater petrosal nerve)
Submandibular ganglion to submandibular gland via chorda tympani
Describe the pathway of CN IX in the PS nervous system
Inferior salvatory nucleus to the otic ganglion
Otic ganglion to the parotid gland via the auriculotemporal nerve
Where is the ciliary ganglion located?
Between the optic nerve and the lateral rectus muscle
Where is the pterygopalatine ganglion located?
Within the pterygopalatine fossa
Where is the submandibular ganglion located?
Suspended from the lingual nerve, close to the submandibular gland
Where is the otic ganglion located?
Directly below the foramen ovale
Describe the pathway of CN X in the parasympathetic nervous system
Presynaptic neurones travel from the dorsal nucleus of vagus nerve and nucleus ambiguus
Found within the carotid sheath
Synapse with postganglionic fibres in ganglia close to or within the target organ
What are the divisions of the nervous system?
Central (brain and spinal cord) and peripheral (motor neurones and sensory neurones)
Motor neurones (somatic and autonomic)
Autonomic (sympathetic and parasympathetic)
