Autonomic Nervous System Flashcards
Functions of the ANS
-Controls all involuntary functions
e.g.) Heart rate, BP, GI mobility, Iris diameter
-ANS is seperate from voluntary (somatic) motor system
-Entirely efferent (regulated by afferent inputs)
What does the sympathetic and parasympathetic system do to achieve homeostasis response of the whole body
Sympathetic: predominates in stress, ‘fight or flight’
Parasympathetic: predominates in basal state, ‘rest and digest’
Anatomical divisions of the sympathetic and parasympathetic nervous system
Sympathetic: Thoracic and lumbar spinal cord
Parasympathetic: Brain stem, sacral spinal cord
What is the autonomic nerve at cranial nerve no.10
Vagus
What are the principal neurotransmitters in the ANS
Acetylcholine
Noradrenaline (Norepinephrine)
Examples of cholinergic sympathetic post-ganglionic neurons
-those innervating sweat glands, hair follicles
-release ACh that acts as at muscarinic ACh receptors
Describe NANC transmitters and its examples
Non-adrenergic non-cholinergic transmitters
Examples: ATP, NO, 5-hydroxytryptamine (e.g. serotonin), neuropeptides (e.g. substance P)
What are sympathetic postganglionic neurons in the adrenal glands differentiated into
Neurosecretory chromaffin cells
What are chromaffin cells
Postganglionic sympathetic neurons that don’t project to a target tissue
What and where do chromaffin cells release at sympathetic stimulation
Adrenaline is released into the bloodstream
Define ‘Chronotropic’ and ‘Inotropic’
Chronotropic: Effect on HR
Inotropy: Effect on force of contraction of muscle fibres
How is acetylcholine synthesised
acetyl CoA + choline → acetylcholine + coenzyme A
Via Choline acetyltransferase
How is acetylcholine degraded
acetylcholine → acetate + choline
Via (acetyl) cholinesterase (AChE)
‘SLUDGE’ Syndrome
Mnemonic for the pathological effects indicative of massive discharge of the PARAsympathetic nervous sysem
Salivation: stimulation of the salivary glands
Lacrimation: stimulation of the lacrimal glands
Urination: relaxation of the urethra internal sphincter muscle & detrusor muscle contraction
Defecation
Gastrointestinal upset: smooth muscle tone changes causing GI problems, including diarrhoea
Emesis: vomiting
Causes of SLUDGE syndrome
Drug overdose
Ingestion of ‘magic’ mushrooms
Exposure to organophosphorus insecticides
Exposure to nerve agents (e.g. sarin)
