Parasympathetic Nervous System Flashcards
where does the oculomotor of the parasympathetic nervous system synapse
Comes from the mid brain and will synapse at the ciliary ganglion and result in pupillary constriction
Where does the facial nerve of the parasympathetic nervous system synapse
-From the pronto- medulary junction - (junction in ponds and medulla)
synpases in prontopalatine ganglion and supplies paratoid glands
- synapses in submandular ganglion and supplies the salivary glands
What are the parasympathetic ganglia of the head
COPS ciliary= innovates lend of eye muscle Otic- ear gland Pterygopalatine- lacrimal gland Submandibular = salivary gland
What does the vagus nerve of the parasympathetic target supply
- heart, trachea, lungs, stomach, small intestines, liver, large intestine, adrenal gland, kidney (distal thrid of tranverse colon)
What neurons in the parasympathetic NS supplies large intestines, bladder and reproductive organs
S2-S4= post ganglionic neutron is the PELVIC SPLANCHNIC NERVE (sacral fibres)
What receptors do ACh effect in para
IN THE CNS
- nicotinic preganglion
- muscarinic in post ganglion
What are the 6 steps of chogenic transmission of Ach
- Supply (transmitter precursor)
- synthesis (transmitter)
- storage. ((transmitter)
- release. (transmitter)
- inactivation (transmitter)
- feedback (inhibition of release)
What does it mean by the supply of Ach and what drug do we associate with it
- uptake of choline into nerve endings (High affinity carrier)
- Na+ dependent reaction
- Hemicholinium = -competitive inhibitor of choline
- activity dependent block of cholinergic transmission
- no clinical use as too wide spread
- more stimulate more effective H is
What is the synthesis of Ach and competitive inhibition for the enzyme
- Ach catalysed by ChAT
- triethylchlone competitively binds to choline acetyltransferase (ChAT)
What is the equation for Ach
Choline+ Acetyl co enzyme A—-> acetylcholine + coenzyme A
What is the storage mechnism for Ach and drug inhibition of stores
- the Ach store maintained through energy dependent pump
- vesamicol drug - inhibition of pump- depletion of stores
What does Acetyltriethylcholine do and how is it formed
- formed from triethylcholine catalysis by choline acetyl transferase
- not specific released as false transmitter
- weak postsynaptic effect
- depends on how potent postsynaptic receptors are compared to with natural transmitter
How will Ach be released
- binds to cell membrane
- requires Ca 2+ into nerve endings
- released by exocytosis
How does Ach give feedback
- Ach act back onto MR inhibits neurotranmitter release
- can work with ATP to cause inhibition of adenosine receptors
How is Ach removed from synaptic cleft
- hydrolysis by tissue acetylcholinesterase
- broken down from acetylcholine to acetate and choline
- non reversible
Which enzymes and what inhibits acetylcholinesterase and amplify chologernic transmission
- neurostigmine enzyme
- SARAN gas
- VX
What drugs block the release of Ach
- black widow spider venom (a-latrotoxin) - causes random release of Ach causing muscle spasms
- botulinum toxin
What is botulium toxin used to treat clinically
- salivary drooling, achalasia, cosmetic reasons, biological warfare, blepharospasm
What are examples of neurotransmitters that inhibiit neurotransmitter release in receptors
- Ach musc inhibits Ach ent
- Ach nicht inhibits Ach
- ATP- adenosine inhibits A1 receptor
- morphine opioids inhibit opioide receptors- leads to constipation (messes with gut function)
- NA inhibit a- adrenoreceptors SYMATHETIC CROSS INHIBITION
What agonists bind to muscarinic receptors and mimic effect of parasympathetic nerve stimulation
- Ach
- carbachol
- muscarine
- pilocarpine
- oxytremorine
all mimic effects of parasympathetic stimulation
What do we use for Glucoma treatment of the eye
- pilocarpine - drains fluid and reduces eye pressure
- misuse as mushroom poisoning and is toxic
Why do we never use muscarinics agonist systemically and always locally or tropically
- lots of musc receptors in body
- effect = decreased heart rate
- smooth muscle contracts, vascular dialates
- exocrine gland- sweating, salivation, bronchial secretion, lacrimation
How does atropine cure side effects of acetylcholine antagonists such as niostigmine?
- used in surgery, reverses amplified parasympathetic transmission of niostigmine after being given to reverse paralysis
- stops some symptoms of. chemical weapons such as SARIN
How does hyoscine cure motion sickness
ANTIMUSCARINIC
- nausea and sickness
- inhibits chologernic transmission in gut- less nausea and sickness
- muscarinic receptors also in brain so works in CNS
