Week 3 Parasympathetic Nervous System ✅ Flashcards
Which spinal nerves are part of the parasympathetic nervous system?
Sacral vertebrae - sacral plexus
Cranial nerves
What is the difference between pre- and post-ganglionic parasympathetic nerves?
Pre-ganglionic = long
Post-ganglionic nerves = short
Where are nicotinic receptors located?
Pre-ganglionic nerve endings and neuromuscular junctions of skeletal muscle
What branch of the nervous system controls blood vessels?
Sympathetic
What neurotransmitter do muscarinic and nicotinic receptors use?
Acetylcholine
How do muscarinic receptors work?
Opens K+ channels –> hypokalaemia –> slows depolarisation –> HR decrease
also open Ca channels –> increased peristalsis –> constipation relief
How does the vagus nerve affect heart rate?
Releases ACh –> binds to muscarinic receptors –> K+ leaves cells –> SAN/AVN depolarisation slows
What is an example of a muscarinic agonist?
Pilocarpine
In which branch of nervous system are muscarinic receptors?
Parasympathetic
What is an example of a muscarinic antagonist?
Atropine
What is the difference between muscarinic agonists and antagonists?
Agonists stimulate parasympathetic, antagonists inhibit parasympathetic
What is the effect of a muscarinic agonist?
Miosis
Low IOP
Stimulates saliva production
What is the effect of a muscarinic antagonist?
Mydriasis
Treats bradycardia
What is ipratropium?
Short acting muscarinic antagonist
What is tiotropium?
Long acting muscarinic agonist
