When ACh stimulates muscarinic receptors, some effects are…
Eyes:
- Miosis (pupil constriction)
- Lacrimation (tear secretion)
- Accommodation for near vision (the lens of the eye becomes set for reading)
- Decreasing intra-ocular pressure (useful for glaucoma)
Digestive tract (remember it helps with digestion):
- Saliva secretion which breaks food down
- Stomach acid secretion
- Peristalsis
Other effects:
- Decreased heart rate
- Bronchial constriction (makes it hard to breath in asthmatics)
- Enhanced urination (by relaxing the sphincter and contracting the bladder)
Again, all these are parasympathetic effects from acetylcholine stimulating the muscarinic receptor.
