Autonomic Nervous System (plus pharmacology of ANS and NMJ) Flashcards
What nerves does the autonomic NS respond from
Efferent nerves (motor neurons)
Whats Voluntary, somatic or autonomic
somatic
Whats a ganglion
group of nerve cell bodies linked by synapse passing on AP O—-C O—–C
Whats the swelling on a nerve fibre
Ganglion
Somatic differences to Autonomic
Specialised NMJ, isotropic receptors, always excited the cell,
What does Somatic NS always have
a large endplate potential
What receptors do Autonomic NS have
Metabotropic
what are Metabotropic receptors
G protein-coupled receptors
What does Autonomic system split into
Parasympathetic and sympathetic
Parasympathetic where does ganglia lie
Ganglia lies closer to target, therefore long preganglionic fibres
Postganglionic fibre longer found in
Sympathetic
Sympathetic system exits from
Thoriac and Lumnar regions of the spinal chord T1-12 L1-2
White rams =
preganglionic fibres
Grey rams =
postganglionic fibres
Ramus
Communication branch
All ganglion fibres activated at same time by
convergence and divergence
ACH works on what receptors
cholingeric
Examples of cholingeric receptors
Nicotinic and muscarnic
Parasympathetic release what NT at preganglionic fibre on to what receptor
ACH on to nicotinic
A muscarnic receptor is
G protein coupled
Sympathetic post ganglionic fibre releases whats NT on to what receptor
Noradrenaline on to either alpha or Beta receptor
Parasympathetic post ganglionic fibre releases whats NT on to what receptor
ACH on muscarnic receptors
At a preganglionic fibre ACH is released on to what receptor into what NS
Parasympathetic and Sympathetic
Alpha 1 receptors cause
Contraction
Beta 2 receptors cause
Dilation
Noradrenaline NT only acts on what receptors
adregeneric
Examples of adregenric receptors
Alpha and Beta
Whats are Muscarnic receptors responsible for
smooth muscle
Parasympathetic NS exits spinal chord from
cranial
Sympathetic NS acts on salivary gland release what NT instead
ACH instead of noradrenaline
Non adregenric non cholingeric receptors (NANC) examples
Peptided and Nitric Oxide
Whats do NANC do
are correlated or released on their own
Sympathetic NS can release noradrenaline directly into (what does the show)
the blood, hormonal properties
Cholineric receptors are
ionotropic type receptors with an integral ion channel
Cillary Muscles contract in the eye, constricting pupil this is due to
ACH acting on muscarnic receptor in parasymathetic NS
For the Eye to focus close up
Cillary muscle contract and radial muscle dilate
The work of the Cillary muscle and the radial muscle in the eye is called
muscarinic anatgonist
Eyes Dilate and focus far away by
noradrenlaine acting on B2 to relax the lens and A1 constricting the iris, dilating pupil allowing more light in to see far away
What makes the heart contract
pacemaker cells depolarise
Whats increase heart rate
noradrenaline acting on the beta receptors
Parasympathetic NS has little effect on what in the heart
strength of hearts contractions
B2 agonsits in the lungs e.g. and function
Salbutamol, dilates airways
Parasympathetic NS on the eye activates and causes what to the spinchter
Activates muscarinic receptors on sphincter muscle
Contracting & makes pupil smaller
Parasymatheric has what effect on Blood Vessels
No effect
Sympathetic NS alpha receptors cause what to happen in BV
Cause smooth muscle to contract in blood vessels
What cause the BV to dilate and increase blood flow
Noradrenaline acting on Beta receptors
why due to Tonic activity does parasympathetic have little effect
means there is always an ongoing activity hence why parasympathetic has little activity e.g. smooth muscle always a little but contacted
Parasympathetic on the Gut
muscarnic receptors on gut wall increase gut mobility and muscarnic receptors on pancreas increase enzyme secretion
Single intervention means
Controlled by tonic activity
sympathetic system stimulates what two procedures in energy stores and increase what
glycogenolyis & gluconeogenesis
Increases lipolysis
what is dual intervention
innervated by both sympathetic and parasympathetic fibers
Example of dual intervention
Salivary gland, Parasymapthetic releases watery solution whilst sympathetic releases tick secretion rich in enzymes
What do Beta receptors trigger in the bladder
relax smooth muscle of bladder wall, therefore reducing pressure
sympathetic NS alpha receptors in the bladder cause
contract smooth muscle of sphincter and prevent urinations
Whats controls the autonomic NS
Autonomic reflexes hypothalamus
examples of autonomic receptors
baroreceptors detect blood pressure then influence activity
What does hypothalamus do
coordinates autonomic, somatic and endocrine activity in a defence response
Dual Intervention of reproductive tract
sympathetic causes ejaculation as Parasympathtic causes erection
A dual intervention has
complimentary effects
How can you stop efficiency of NMJ synapse
stop the Ach being packaged into the vesicles
Block Voltage gated calcium channels
Block vesicles fusing with receptors
Competitive antagonist stop ach activating receptor
Whats blocks choline transport
hemicholinium
what does black widow spider toxin
blocks the voltage gated Ca2+ channels
Depolarising nicotinic receptors does what
continue to open cells, keeping cell depolorised therefore can’t fire AP, (short lasting action, can cause damage)
Increases activity of NMJ synapse
Prolong AP,
Block acetylcholinesterase
How do you prolong an AP in NMJ Synapse
Increase the number of calcium ions, increasing response
Whats happens when you block acetylcholinesterase
ach hangs around synaptic cleft therefore activates more receptors and increases transmissions
why would you want to block NMJ synapse
paralyse patients during surgery or ECT
Non-depolarising or depolarising blockers used for paralysis during
surgical procedures
electroconvulsive therapy
controlling spasms in tetanus
Botulinum toxin used for
treating muscle spasm
cosmetic procedures
Anti-cholinesterases used for
treating myasthenic syndromes
reversing action of non-depolarising blockers
countering botulinum poisoning
what includes both the sympathetic and the parasympathetic systems
connections between the preganglionic and the postganglionic autonomic fibres ach–nicotinic
Whats receptors is present more in ganglionic receptor than NMJ receptor
nicotinic
what is ganglia sensitive to that blocks ach channel
hexamethoneuns
Why aren’t there any clinical applications to modifying ganglionic transmission
as drugs would modulate both sympathetic and parasympathetic ganglionic transmission, therefore producing a range of complex signals
whats do most therapeutically drugs target
postsynaptic muscarinic receptors
Muscarinic agonists and antagonists
mimic or block effects caused by parasympathetic ns
whats is glaucoma
raised intraocular pressure
alpha agonists work the same usually as
beta blockers
what do alpha agonists and beta blockers do in glaucoma
reduce the production of the aqueous humour fluid in the eyeball
For glaucoma what does a muscarinic agonist do
contract the ciliary muscle supporting the lens,contract sphincter muscle of cell and seem to open up the trabecular network so aqueous humour drains through
How can you manipulate postganglionic sympathetic transmission
By manipulating release of noradrenaline and adrenergic
How do you inhibit postsynaptic sympathetic transmissions
Block enzyme producing noradrenaline Block transporter that fills vesicles introduce a fals transmitter Block alpha/beta postsynaptic receptors activate inhibitory presynaptic autoreceptors inhibit volatge gate calcium channel
What enzyme is blocked in the production of noradrenaline
dopadecarboxylase (dopa-dopamine)
increase efficiency of postganglionic sympathetic transmission
stimulate noradrenaline release
inhibit uptake of noradrenaline from cleft back into neurones
Activate postsynaptic receptors
Indirectly triggers the release noradrenaline is called
sympathomimetics
what does cocaine do
inhibits uptake carrier leaving noradrenaline in synpatic cleft to activate postsynaptic receptors
Noradrenaline breakdown
transmitter unactivated and only broken down in cells
what are alpha 2 agonists clinical applications
treatment of hypertension
what are beta2 agonists clinical applications
treatment of asthma e.g. salbutamol
what are alpha 1 agonists clinical applications
used as decongestants and to dilate the pupil
what are beta1 antagonists clinical applications
treatment of hypertension, angina and glaucoma