nerves , ANS and PNS. Flashcards
pharmacology of the autonomus nervous system.
what are two types of nervous system
peripheral and the central nervous system
divisions of the PNS
autonomic and somatic nervous system
what is the autonomic nervous system made up of
parasympathetic and sympathetic fibres
what is the anatomy of the sympathetic nervous system
the fibres branch of from the thoracolumbar region that is T1 to T12 and L1 to L12
what is the difference between the anatomy of the somatic nervous system and the autonomic
-the somatic nervous system does not pass through the ganglion
ANS fibres are divided into preganglionic and postganglionic fibres.
- For the somatic nervous system there is Specialised NMJ
Ionotropic receptors
Always excites target.
-For the autonomic nervous system is less specialised , there is the use of metabotropic receptors , may excite or inhibit target cell.
where is parasympathetic outfow from
Parasympathetic outflow is from cranial (III, VII, IX, X) and sacral (S2-4) regions
location of the ganglia
Sympathetic ganglia lie close to spinal cord in the sympathetic chain (paravertebral ganglia), or in collateral (prevertebral) ganglia.
Parasympathetic ganglia lie close to or within the target
autonomic receptors for acetylcholine
Acts on cholinergic receptors
Nicotinic receptors
Muscarinic receptors
autonomic receptors from noradrenaline
Acts on adrenergic receptors
α receptors
β receptors
what neurotransmitter is released in the preganglionic stage for parasympathetic and sympathetic ?
Both release acetylcholine that acts on cholinergic receptors in this case nicotinic receptors
what neurotransmitter is released post ganglionic for parasympathetic
acetylcholine that acts on muscarinic cholinergic receptors
what neurotransmitter is released post ganglionic for the sympathetic nervous system
noradrenaline that acts on adrenergic receptors that is either beta or alpha receptors
exceptions to the normal neurotransmitters used
Some postganglionic fibres have not read the textbook
Sympathetic cholinergic fibres innervate sweat glands
Some postganglionic fibres use non-adrenergic non-cholinergic (NANC) transmitters e.g. peptides
which can sometimes be released with the orthodox transmitters that is noradrenaline and ACh
sympathetic effect on the eyes
pupils dilate , eye focuses away
sympathetic effect on the heart
heart beats faster and stronger
effect of sympathetic on energy stores
stored energy is released
overview of parasympathetic effect
Airways constrict
Heart beats slower
Heart beats weaker
Blood diverts to gut
Gut motility increases
Enzyme secretion in gut
generally stimulated
Energy is stored
Pupils constrict
Eyes focus close up
Hair lies flat
Mouth starts drooling
sympathetic effect on the radial muscle of the iris
alpha 1 receptors activated on the radial muscle ( outside ring muscles ) this makes the pupil larger and wider
parasympathetic effect on the sphincter (inside )muscle of the iris
contracts the sphincter muscle ( inside muscle )of the eye to make the pupil smaller.
Acts on the muscarinic receptors
parasympathetic effect on the ciliary muscle
(CL- CILIARY FOR LENS)- contraction and the eye focuses close up
sympathetic effect on the ciliary muscle
Activation of the B2 receptors on ciliary muscle which causes relaxation of the ciliary muscle causes the lens to focus far away
heads up for adrenergic receptors
alpha 1 are used for contraction
beta 2 used for for relaxation
sympathetic effect on the heart
activation of beta 1 receptors on the pacemaker cells which increases heart rate
activation of of beta 1 receptors on the myocytes ( cells of the heart )causes increased strength of contraction .
parasympathetic effect on the heart
activation of the muscarinic receptors on the pacemaker cells causes a decreased heart rate , little effect on the myocytes.
types of the cells targeted by neurotransmitters in the heart
pacemaker cells and the myocytes
sympathetic effect on the lungs
airways are dilated through the action of b2 receptors which makes smooth muscles to relax.
medication that is used for relaxation of the airways
targets the beta 2 receptors ( beta 2 agonist ) example is salbutamol( think of inhaler that is made up of salbutamol )
example of the beta one antagonist drug
atenolol which decreases the heart rate and has limited effect on the airways .
sympathetic effect on blood vessels
-activation of the alpha 1 receptors that cause the contraction of the smooth muscles of the blood vessels - causing reduced blood flow to non essential regions like the skin
-activation of the beta 2 receptors which causes dilation and increases the flow of blood in essential regions like the heart.
effect of sympathetic on salivary glands
stimulation of b receptors which release the secretion of thick and rich enzymes.
example of tone innervation
innervation of the smooth muscles if the blood vessels.
example of dual innervation with non antagonistic action
secretion of saliva
sympathetic effect on the bladder
activation of the beta 2 receptors on the smooth muscle of the bladder wall which relaxes and reduces pressure .
activation of the alpha 1 receptors of the sphincter smooth muscles and this causes the muscle to contract and stop urination
effect of sympathetic on the reproductive system
activation of the alpha 1 receptors of the smooth muscle that causes contraction
of the smooth muscle and results
in ejaculation .
types of autonomic reflexes
spinal reflexes or learned reflexes
central control of the nervous
Integrated in the brain, mainly hypothalamus, thalamus and brainstem
e.g. baroreceptor reflex
Baroreceptors detect changes in blood pressure
Integrating centre looks at the information
Coordinates a sympathetic and parasympathetic outflow to vary heart rate, strength of contraction, and constriction of blood vessels accordingly
what are the receptors present in the autonomic nervous system pharmacology
adrenergic and cholinergic receptors
ways of inhibiting transmission in a neuromuscular junction
inhibiting choline transporter example hemicholinium.
blockage of voltage gated calcium ion channels .( spider widow fusion )
Blocking vesicle formation for example ( botulinium toxins)
use of non -depolarising nicotinic receptor blocker.
use of depolarising nicotinic receptor blockers eg tubocuranine
where does pharmacological modification take place in
in the synaptic junction
ways of potentiating transmission
blocking acetylcholinesterase
clinical applications of pharmacological modification
Non-depolarising or depolarising blockers used for paralysis during:
Surgical procedures
Electroconvulsive therapy
Controlling spasms in tetanus
Botulinum toxin
Treating muscle spasms
Cosmetic procedures
Anti-cholinesterases
Treating myasthenia gravis
Reversing action of non-depolarising blockers
Countering botulinum poisoning
