Cervical autonomic nervous system Flashcards
Define the central nervous system
the central nervous system is composed of the brain and spinal cord
Define the peripheral nervous system
The PNS is composed of all the motor (efferent) and sensory (afferent) neurons out with the brain and spinal cord and can be divided into autonomic and somatic nervous system
Define the autonomic nervous system
The autonomic system controls viscera (involuntary responses) and can further be divided into sympathetic and parasympathetic nervous system.
the function is to control involuntary physiological processes
Define the sympathetic nervous system
The sympathetic nervous system sends motor innervation to the body core (viscera) and body periphery (eg blood vessels and sweat glands)
Define the parasympathetic nervous system
The parasympathetic nervous system only sends nerves to innervate the core (viscera)
The enteric division is also a division of the autonomic nervous system, what is its function?
The enteric division of the autonomic nervous system works in conjunction with CNS to regulate the digestive system
Describe the relationship of the sympathetic and parasympathetic nervous system
Both systems work in synergy- brake and accelerator analogy.
There is an increase in sympathetic in stress - incr BP, blood sugar, blood flow to skeletal and away from viscera, dilation of pupils, decreased saliva)
and there is an increase in parasympathetic when sedentary (opposite effects)
What is a ganglion?
A ganglion is a collection of nerve bodies within PNS
Where do visceral motor nerve synapse?
All visceral motor nerves synapse in peripheral ganglion
Where are the cell bodies of all sensory nerves?
All sensory (somatic and visceral) have their cell bodies in a spinal ganglion
Describe the organisation of an autonomic pathway
All autonomic pathways are efferent and consist of 2 neurons which synapse in a ganglion
- preganglionic neurons are myelinated
- post ganglionic neurons are non-myelinated
What is the difference between preganglionic neurons in sympathetic v parasympathetic divisions?
Preganglionic neurons are shorter in sympathetic
What is a synaptic cleft?
A synaptic cleft is the space between the axon terminal of one neuron, dendrite of receiving neuron and glial process
name common neurotransmitters with excitatory effect
acetylcholine and noradrenaline both have excitatory effects
what is the name given to fibres which release ACh?
Neurons which release ACh = cholinergic
What is the name given to neurons which release noradrenaline?
neurons which release noradrenaline = adrenergic
What is the origin of parasymapthetic neurons and location of cell bodies?
cell bodies are in nuclei in the brain stem
where do preganglionic cell bodies of sympathetic neurons originate?
preganglionic bodies of sympathetic neurons originate in lateral horn of spinal cord
where do the preganglionic sympathetic neurons leave the spinal cord?
the preganglionic sympathetic neurons leave the spinal cord via ventral root (motor fibres, sensory in dorsal root)
What is the sympathetic trunk?
The sympathetic trunk is a chain of ganglia which contains cell bodies of postganglionic fibres - can either synapse in ganglia at the same level or travel up/ down the chain to synapse with ganglia at different level.
they exit through grey rami communicantes
where do sympathetic preganglionic fibres destined for the head region synapse and travel?
sympathetic preganglionic fibres destined for the head synapse in the superior cervical region- post ganglionic fibres then travels into head along surface of ICA and carotid plexus
what are the branches of the superior cervical ganglion (sympathetic trunk)?
The superior cervical ganglion supplies branches via:
- ICA and ECA (carotid plexus)
- cervical spinal nerves (C1-4 - cervical plexus)
- pharynx
- superior cardiac nerves
what are the branches of the middle cervical ganglion (sympathetic trunk)?
The middle cervical ganglion supplies branches via:
- cervical spinal nerves (C5-6)
- middle cardiac nerves
what are the branches of the inferior cervical ganglion (sympathetic trunk)?
the inferior cervical ganglion supplies branches via:
- vertebral artery (forming a plexus)
- cervical spinal nerves (C7-T1, C7 and 8 to brachial plexus)
- inferior cardiac nerves
what is the function of the cervical ganglia of the sympathetic trunk?
cervical ganglia regulates sympathetic innervation of eyes, eyelids, lacrimal glands, carotid body, salivary glands, sweat glands
What is Horner’s syndrome?
Horner’s syndrome is damage to cervical sympathetic trunk resulting in absence of sympathetically stimulated functions on ipsilateral side of head.
describe the clinical signs and symptoms of Horner’s syndrome?
Horner’s syndrome:
- miosis (constriction of pupil)
- ptosis (drooping of superior eyelid)
- flushed face and anhidrosis (vasodilation and absence of sweating of face/ neck)
where are preganglionic neurons of parasympathetic ganglia located?
preganglionic parasympathetic neurons are located in cranial and sacral regions of CNS
where are preganglionic neurons of parasympathetic ganglia located?
preganglionic parasympathetic neurons are located in cranial and sacral regions of CNS
where are preganglionic neurons of parasympathetic ganglia located?
preganglionic parasympathetic neurons are located in cranial and sacral regions of CNS
Which cranial nerves have parasympathetic visceral afferent fibres
CN 3, 7, 9 and 10 have visceral afferent fibres
What is ciliary ganglia?
located between optic nerve and lateral rectus
preganglionic neurons of occulomotor (CN 3) travel to ciliary ganglion- postganglionic innervate ciliary muscle and sphincter (controls pupil)
What is pterygopalatine ganglion/ submandibular ganglion?
pterygopalatine- located in superior part of pterygopalatine fossa, neurons of facial nerve synapse with pterygopalatine ganglia
submandibular- lies in vicinity of submandibular gland
both innervate lacrimal gland and nasal mucosa and submandibular gland
Fibres from facial nerve (CN 7)
What is otic ganglion?
Lies in infratemporal fossa, below foramen ovale
preganglionic fibres of glossopharyngeal nerve (CN 9) synapse with otic ganglion- parotid gland via auriculotemporal nerve (wraps around middle meningeal artery)
also carries visceral afferent information from chemoreceptors/ baroreceptors in carotid body/ sinus.
where do preganglionic fibres of vagus nerve (CN 10) travel to?
preganglionic fibres of CN 10 travel from dorsal nucleus of vagus nerve and nucleus ambiguus and synapse with muscle of thoracic and abdominal organs, which they then supply
