Autonomic Nervous System Flashcards
Define Autonomic Nervous System (ANS)
Functional division of nervous system that is not voluntarily controlled
Define Somatic Nervous System
Functional division of nervous system that is voluntarily controlled
Define Sympathetic Nervous system
Branch of autonomic nervous system that opposes effects of parasympathetic division
Define parasympathetic nervous system
Branch of autonomic nervous system that opposes effects of sympathetic division
Catecholamines are:
- Biogenic amines derived from tyramine including dopamine, epinephrine, norepinephrine
- Produced from tyrosine in adrenal medulla and postganglionic fibers of sympathetic nervous system
Function of Autonomic nervous system
Deals primarily with control and visceral functions necessary for life (non-voluntary)
- cardiac output
- Blood flow and distribution
- Digestion
Autonomic nervous system comprised of two branches:
Sympathetic nervous system(adrenergic) -Fight & flight
Parasympathetic (Cholinergic) - Res and digest
Stimulation of Sympathetic and parasympathetic nervous system results in effect on:
eyes
salivation
skin
respiration
heart
digestion
adrenal glands
pic 2 parasympathetic
What are the neurotransmitters of the SNS
Epinephrine, Norepinephrine, Dopamine
Dopamine of a precursor of
Norepinephrine and ephedrine
Where is most NE secreted
Synaptic clefts
NE is also found in bloodstream, normally exists in concentrations 3x greater than epinephrine
Where is most epinephrine produced
Adrenal glands (80%), rest by brain
What neurotransmitter is found in the PNS
Acetylcholine
Receptors (alpha,beta and DA), where are they located and result of stimulation
pic receptor
What effect will Beta2 stimulation have on the ciliary muscle
Relaxation (suppresses accomodation)
Increased aqueous production (IOP)
(alpha2 stimulation decreases IOP)
Mydriasis results from stimulation of which receptor
Alpha 1
Alpha1 receptors are more sensitive to NE or E?
NE (also stimulated by high doses of D)
Alpha 2 receptors are more sensitive to NE or E
E more than or equal to NE
Beta2 receptors more sensitive to NE or E
E is a lot morethan NE
What is the t1/2 of catecholamines
1-3minutes
85% of synaptic NE is non-enzymatically inactivated by reuptake
direct acting sympathomimetic drugs
Bind to and stimulate same receptor as the endogenous neurotransmitter eg phenylephrine
Beta1 receptors more sensitive to NE or E
Equal (also stimulated by high doses of D)
Indirect acting sympathomimetics
Stimulate release of neurotransmitter from a nerve terminal eg amphetamine
Block the reuptake of neurotransmitter from the synapse, prolonging effect eg cocaine
Sympathomimetic adverse effects regarding CVS
Increased heart rate
Arrhythmia
Elevated blood pressure
Ocular sympathomimetic side effects
Mydriasis & suppression of accommodation leading to light sensitivity
Reduced depth of focus and near blur
Sympathomimetic adverse effects regarding CNS
Hemorrhagic stroke
Anxiety
Fear
Headache
Tremor
Hepatic sympathomimetic adverse effect
Elevated blood sugar
Immune system and respiratory sympathomimetic adverse effect
Immunosuppression
Pulmonary edema
Effect of M3 stimulation on eyes
Miosis
Cilliary muscle contraction and increased aqueous outflow
Increase in ocular gland secretion
Ocular anticholinergic side effects
Increased IOP
Angle closure risk
Alergy
Systemic anticholinergic side effects
ABCDss
-Anorexia
-Blur
-Constipation
-Dryness
-Sedation
_Stasis of urine
Thirst, tachycardia. hypertension, decreased glandular secretions(sweat/bronchial/saliva) > heart/smooth muscle > GIT
CNS anticholinergic side effects
Decreased parkinson tremor
Decreased heart rate
What is the anticholinergic toxidrome
Blind as a bat (blur)
Hot as desert (hyperthermia)
Mad as a hatter (Confusion)
Dry as a bone (Dry mouth,urinary retention)
Red as beet (flushed skin)
Tachycardia
absent bowel sounds
shaking
dilated pupils
How do neuromuscular blocking agents work
Act on motor neurons where they block Acetylcholine-based contraction of muscle fibres
(Nicotinic acid ACh receptors are ligand gated, stimulation leads to Na+ influx and generation of action potential that results in contraction
How do botox and tetanus produce muscle paralysis
Inhibiting degranulation of ACh vesicles in the presynaptic neuron
Blocking ACh release
Acetylcholine is broken down into…
Acetate + choline by Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) (enzymes)
Activity of Depolarizing Neuromusclular blocking agents (NMBA) act
Initially depolarize the skeletal muscle fiber, desensitizing it to ACh stimulation
These drugs are sustained by AChE/ BChE inhibitors (prolonged by AChE)
Stimulates somatic nicotinic receptors at neuromuscular junctions resulting in initial phase of depolarization and short term paralysis
Degraded slower than ACh by circulating BChE
Commonly results in post-op pain
eg Succinylcholine
How is the effect of non-depolarizing NMBA’s reversed
By AChE inhibitors
Activity of Non-depolarizing NMBA’s
Most common clinically used
Reversable Competitive antagonists at ACh receptor
Reversed by AChE inhibitors through ACh competition
eg pancuronium
Side effects of depolarizing NMBA’c
Elevated IOP common
Respiratory depression
Arrythmia
Bradycardia
Cardiac arrest
Contraindications of depolarizing NMBA’s
Angle closure glaucoma
Penetrating eye injury
Adverse effects of Nonpolarizing NMBA’s
Elevated heart rate and BP
Respratory depression
Contraindications of nonpolarizing NMBA’s
Angle closure glaucoma
Penetrating eye injury
(cation in Myasthenia Gravis and pulmonary disease)
Atropine is an antidote to which receptor effects
Muscarinis, not the nicotinic(muscular) effects
What medication is an antidote to all receptor effects regarding anticholinergic poisoning
Pralidoxime - cleaves bond formesby organophosphate and AChE
Which drugs are used in anticholinergic poisoning and neurodegenerative disease therapy such as parkinsons and alzheimers
Acetylcholinesterase inhibitors
eg Neostigmine
Pyridostigmine
Echothiophate (irreversable and used in glaucoma)
Adverse effects of Neostigmine (Acetylcholinesterase inhibitor)
SLUDGE
Salivation
Lacrimation
Urination
Defecation
GI distress
Emesis
Severe: Anaphylaxis, arrhythmias ,severe hypotension, respiratory arrest
