Module 5 - Peripheral Nervous System Flashcards
What are the two divisions of the peripheral nervous system?
Automatic nervous system and somatic nervous system
What is the role of the automatic nervous system?
Regulates involuntary processes (HR, digestion, respiration)
What is the role of the somatic nervous system?
Carries sensory information from organs to SNS and relayed motor commands
What are the two divisions of the automatic nervous system?
Sympathetic NS and Parasympathetic NS
Fight or flight and rest and digest
Describe the neuronal organisation of the sympathetic nervous system
Made of short preganglionic neurons and long postganglionic neurons
Preganglionic neurons release ACh into synaptic cleft which binds to nicotinic receptors
Postganglionic neurons release NA
Describe the neuronal organisation of the parasympathetic nervous system
Made of long preganglionic neurons and short postganglionic neurons
Preganglionic neurons release ACH and binds to nicotinic receptors
Postganglionic neurons release ACh which stimulates muscle receptors
Describe the effects of the sympathetic NS
Dilates pupils, increases heart rate and heart contractility, inhibits digestion, stimulates glucose release, relaxes bladder and stimulates epinephrine and norepinephrine release
Describe the effects of the parasympathetic NS
Contracts pupils, decreases heart rate and heart contractility, stimulates digestion, stimulates gallbladder, contracts bladder and bronchial constriction
What are sympathomimetics?
Mimics stimulation of SNS, may be directly active or indirectly acting
What are sympathomimetics used to treat?
Glaucoma, anaphylaxis, COPD, hypotension and heart failure
Where are beta1 adrenoreceptors located?
Heart (increases HR and contractility)
Where are beta2 adrenoreceptors located?
Smooth muscle (relaxation of airways and increase glucose uptake)
Where are beta3 adrenoreceptors located?
Skeletal muscle and adipose tissue (breakdown of fat and bladder relaxation)
What medications are used for anaphylaxis?
Adrenaline
What does adrenaline primarily act on?
Alpha 1, alpha 2, beta 1 and beta 2 receptor subtypes
What is the action of dobutamine?
Inotropic (modifies speed of contraction) causing vasodilation
What is the action of dopamine?
Inotropic support in acute HF and cariogenic shock
What is the indication of isoprenaline?
Heart block and cardiogenic/septic shock
What is the mode of action of oral decongestants?
Acts on alpha adrenoreceptors on vascular smooth muscle in respiratory tract causing vasoconstriction
What is an example of an oral decongestant?
Pseudoephedrine
What is the mode of action of intranasal decongestants?
Produces vasoconstriction in nasal musics and decreases nasal blood flow
What are sympatholytics?
Alpha or beta adrenergic antagonists which block the effect of sympathomimetics on alpha or beta receptors
What are alpha blockers send to clinically treat?
Hypertension
What are beta blockers used to clinically treat?
Ischaemic heart disease, essential hypertension, cardiac arrhythmias and congestive heart failure
Which drugs enhance cholinergic effects?
Parasympathomimetic drugs
Which drugs inhibit cholinergic effects?
Anticholinergic drugs or parasympathetic antagonist
What is the mode of action of cholinesterase inhibitors?
Decreases breakdown of acetylcholine, reducing deficiency of cholinergic neurotransmitter activity
What does the mnemonic BAG the PUDDLES stand for in relation to acute toxicity?
Bronchoconstriction
Apnea
Graying of vision
Pupillary constriction
Urination
Diaphoresis
Defecation
Lacrimation
Emesis
Seizures
What is the mode of action of anticholinergics?
Blocks parasympathetic receptors in lungs (causing bronchodilation and decreased production of mucus)
