Atropine: Muscarinic Blockade Effects

The Mechanism of ActionAtropine is a competitive muscarinic antagonist. In the Autonomic

Nervous System (ANS), it works by "plugging" the receptor sites that acetylcholine (ACh) usually binds

to.The Target: Muscarinic receptors ($M_1$ through $M_5$) located on effector organs (heart,

lungs, glands, eyes).The Action: It prevents the Parasympathetic

Nervous System (the "Rest and Digest" mode) from sending its signals.The Result: The Sympathetic

Nervous System (the "Fight or Flight" mode) becomes dominant by default.What the Animation Should

ShowCardiac: Blocking $M_2$ receptors in the SA node, leading to increased heart rate (tachycardia).Ocular:

Blocking $M_3$ receptors in the iris sphincter, causing pupil dilation (mydriasis).Secretory: Reducing saliva