Autonomic Anatomy Flashcards
What is the role of the autonomic NS
Maintain a constant internal environment
What are the sensory inputs to the ANS?
Visceral receptors within organs
Somatosensory receptors e.g. vision smell proprioception
What is the motor output of the ANS
Smooth muscles found in blood vessels and Gi tract
cardiac muscles
secretory glands
What are the divisions of the ANS and what is their role?
Sympathetic Alert and active (help to prepare for an emergency in extreme situations FFF)
Parasympathetic
Rest and digest energy conservation digestion and emptying
Enteric nervous system
digestion
What are the characteristics of the SNS in terms of neurones?
short preganglioinc neurones and long post ganglionic neurones
Preganglioinc neurone cell bodies located in lateral horn of the spinal cord at T1 to L2 levels
What spinal levels do pregnalgioinc neruones leave the spinal cord to enter the throacicolumbar region
T1-L2
Detail SNS neurotransmission
Release of ACh from preganglionic neurone acts on neuronal nAChR’s
Post ganglionicn neurones release NA that acts on noradrenergic receptors A or B
What are the possible pathways of pregnaglioninc sympathetic neruones after they leaves the ventral horn of the spinal cord and pass into the sympathetic chain ?
Synapse with a post ganglioinc neurone directly at the same vertebral level within the sympathetic ganglion enters the S ganglion via the white rami communicates synapses postganglionic neurone leaves the sympathetic chain via the grey rami communicates
Pregnaglionicn sympathetic fibre could alternatively r enter the S ganglion and travel cephalad or caudad to synapse with post gnaglioninc fibres in the sympathetic ganglia which leave via the grey rami communicates too.
May also directly leave the sympathetic ganglion and leave without synapsing to form prevertebral ganglia elsewhere in the PNS
What are the three prevertebral ganglia?
Celiac ganglion
Superior mesenteric ganglion
Inferior mesenteric ganglion
Whats the difference between a prevertebral ganglion and a paravertebral gnaglion
Paravertebral ganglion occur within the sympathetic chain they have short preganglionic and long postganglionic neurones
Prevertebral ganglion ganglia outside the paravertebral chain neurones have longer preganglionic neurones and shorter postganglionic neurones
Where do parasympathetic preganglionic neurones arise from generally
Craniosacral sources
from specific cranial nerve nucli and from the S2-S4 segments
Outline PNS neruotransmission
Preganglionic neurons release ACh action on nAChR’s on postganglionic neurones
Postganglionic neurone cell bodies located in the walls of target organs
Release ACh too that acts on muscarinic ACh receptors on target tissues
What cranial nerves contribute to cranial sacral sutonomic outflow?
Oculomotor CNIII
Facial CNVII
Glossopharyngeal CNIX
Vagus CNX
What cranial nerve supplies the head region only? What is the other nerve and what does it supply how does it get there?
CN’s III, VII, CNIX only supply the head
vagus supplies visceral in the thoracic and abdominal regions gets there via closely associating with blood vessels
What do the sacral nerves supply?
the viscera in the abdomen and pelvis
What nucleus does cranial nerve III originate from and where is the site of its ganglion?
Ediger-Westphal Nucleus
Ciliary ganglion behind eye
Where do the post ganglionic fibres of CNIII synapse and what is the response
Sphincter pupillae muscles
Causes constriction of pupil
Ciliary muscles
causes contraction results in relaxation of suspense ligaments making lens shorter and fatter and more spherical allowing accommodation to see close up objects
Where does CNVII originate from and where is its ganglion located? (COPS)
Superior salvatory nucleus
Pterygopalatine ganglion
AND
Submandibular ganglion
What do the postganglionic fibres leaving the Submandibular ganglion synapse with and what is the response?
Submandibular gland
Sublingual gland
Increased secretions
What do the postganglionicn fibres of leaving the Pterygopalatine ganglion supply? What is the response?
Lacrimal glands
Nasal mucosa and mucosa of palate
Increased secretions
Where does CNIX originate from and where is its ganglion located? (COPS)
Inferior salvatory nucleus
Otic ganglion
What do postganglionic fibres leaving the otic ganglion synapse with? What is the repsonse?
Parotid gland
Increased secretions
What nucleus do the parasympathetic fibres of the vagus originate from?
The dorsal motor nuclus
Where do preganglionic fibres from the vagus that effect the heart form a ganglion? What do the postganglionic fibres supply and what is the response?
Cardiac plexus
Postganglionic fibres supply the SAN and AVN
Decreases HR and Cardiac output
Where do preganglionic fibres from the vagus that effect the bronchi form a ganglion? What do the postganglionic fibres supply and what is the response?
Pulmonary plexus
synapse with smooth muscle and glands in bronchi
Increased bronchial secretions and bronchoconstriction (don’t need as much air when resting)
Where do preganglionic fibres of the vagus that effect the GIT terminate?
Oesophageal plexus
How is the stomach and small intestine then effected from postganglionic fibres that leave the oesophageal plexus
Increased secretion
Increased motility peristalsis
Relax sphincters
Does this though some direct innervation but also through ENS
FOR BOTH
Where do the sacral nerves originate from and what are the names of some of the ganglia they form?
S2-S4 levels leave the spinal cord and form pelvic splanchnic nerves
Hypogastric plexus
myenteric and mucosal plexus
What are some of the targets of postgnaglionic sacral fibres? What is there effect
Pelvic viscera
sex organs
urinary bladder
colon
Peristalsis Increased secretions Urination contraction of smooth muscle in bladder wall Deification Erection
What is referred pain
Visceral afferent fibres from viscera enter the dorsal root of the spinal cord and essentially mix with sympathetic afferents coming form the skin that are very nerve cell dense from the same spinal level
The signal mixes with the somatic afferents and triggers then to fire action potentials
This sends signals to the brain telling it there is pain in an associated dermatome at the same level as the nerve that supplies the viscera
What is Raynaud’s syndrome
What is the cause
What is the consequence
What are potential treatments?
Overreaction os the SNS in cold conditions resulting in strong vasoconstriction of arteries supplying digits
Occurs due to cold exposure
results in digits going white due to lack of blood flow then bright red as blood flow returns
Is very painful pins and needles sensations
can results in gangrene of the digits if prolonged
Drugs that inhibit sympathetic activity are required (Adrenergic antagonists)
What is Horner’s syndrome?
Why does it occur?
What are the causes?
severe constriction of one of the pupils
This occurs due a lesion in the Sympathetic nervous system that supplies the radial muscles
As such PNS activity dominates only the sphincter pupillae are supplied resulting in meiosis and constriction
Also get loss of sweating on associated side as well as ptosis drooping of the eyelid
Causes include trauma tumours MS spinal coed lesions and stroke
