Autonomic Nervous System Flashcards
The autonomic nervous system is split into two sub groups, what are they?
Sympathetic and parasympathetic
Which two areas of the spine do the sympathetic nerves come from?
Thoracic and lumbar
What do autonomic nerves pass through before going to their target organ?
Ganglia
Which neurotransmitter do all the autonomic efferent from the CNS use?
Acetylcholine
does the adrenal gland use ganglia?
No, it is activated directly by acetylcholine
Which receptor does nicotine work on?
The nicotinic acetylcholine receptor
What type of receptor is the nicotinic acetylcholine receptor?
A ligand dated ion channel
Why do some drugs that use the nicotinic acetylcholine receptor work better on different parts of the body?
Because the nAChR can have different subunits in different areas of the body
Which ion are nAChR permeable to and this allow depolarisation and excitation of the post ganglion is nerve?
Sodium (Na+)
Why do drugs that use the nAChR have lots of side effects?
Because they are all over the body so cannot act locally/specifically
What is an example of a nAChR agonist? And what are it’s effects on the body?
Nicotine
Tachycardia, increased blood pressure, increased secretions, variable GI activity
What is a nAChR antagonist and what are it’s effects on the body?
Tubocurarine
Decreased blood pressure, decreased secretions, GI paralysis
What is the main post-ganglionic neurotransmitter in the sympathetic nervous system?
Noradrenaline
What is the difference between adrenaline and noradrenaline?
Adrenaline is a hormone
Noradrenaline is a neurotransmitter
What type of receptors are adrenergic receptors?
G-protein coupled receptors
What are the characteristics of adrenergic alpha1 receptors?
Gq protein coupled
Causes increased cell Ca2+ and increased cell activity
In blood vessels, GI sphincters, eyes, salivary gland
Constriction
What are the characteristics of the adrenergic alpha2 receptors?
Gi protein coupled
Decreased CAMP and decreased cell activity
In CNS
Decreased sympathetic activity
What are the characteristics of adrenergic b1 receptors?
Gs protein coupled
Increased camp increased cell activity
In the heart
Increase heart rate
What are the characteristics of adrenergic beta2 receptors?
Gs protein coupled Increase CAMP, smooth muscle relaxation In the lungs, blood vessels, smooth muscle Bronchodilaton Vasodilation Uterine dilation
What are the characteristics of adrenergic beta3 receptors?
Gs protein coupled
Increased CAMP
In fatty tissues, skeletal muscle, bladder muscle (metabolically associated)
Lipolysis, thermogenesis, bladder relaxation
What does adrenaline cause the body to do?
Vasoconstriction
Increases heart rate
Bronchodilation
Which adrenergic receptor does noradrenaline have a low affinity for?
Beta2
What is the main post ganglionic neurotransmitter used in the parasympathetic nervous system?
Acetylcholine
What is the main post and pre ganglionic neurotransmitter used in the parasympathetic nervous system?
Acetylcholine
What are the pre and post ganglionic receptors used in the parasympathetic nervous system?
Pre- nicotinic acetylcholine receptor
Post-muscarinic acetylcholine receptor
What are the characteristics of the M1 muscarinic receptor?
Gq protein coupled Increase cell Ca2+ In CNS, GI tract, salivary and eye glands CNS excitation Gastric secretion
What are the characteristics of the M2 muscarinic receptor?
Gi protein coupled
Decrease cell Ca2+
In CNS and heart
Decrease heart rate
What are the characteristics of the M3 muscarinic receptor?
Gq protein coupled Increase cell Ca2+ In Exocrine glands, smooth muscle, GI, salivary, lungs, bladder Gastric and salivary secretion Gi smooth muscle contraction Vasodilation Bronchoconstriction Bladder contraction
What is Atropine?
A highly toxic muscarinic receptor antagonist (non-selective)
What is oxybutinin and what is it us3d for?
Muscarinic non-selective receptor antagonist
Used for bladder incontinence/overactivity
Does the somatic nervous system use ganglia?
No
What must happen for muscle reactivation in the somatic nervous system?
The neurotransmitter must be cleared from the post-synaptic cleft
How is the neurotransmitter cleared from the post-synaptic cleft?
By the enzyme acetylcholine esterase
What is curare?
It is a nicotinic acetylcholine receptor non-depolarising competitive antagonist
It stops muscle movement
What can curare be used for?
Anaesthetic
What is suxamethonium?
A nAChR agonist depolarising blocker
It holds the receptor blocked so Cannot repolarise
Used as muscle relaxant in surgery
What is neostigmine?
An acetylcholine esterase inhibitor
Stops the clearance of ACh from the cleft
Affects all over body
Used as a nerve gas weapon
What are atropine, ipatropium, hyoscine, oxybutinin examples of?
Muscarinic antagonists
