What physiological aspect does Atropine primarily affect?

Atropine primarily affects heart rate and atrioventricular (AV) conduction due to its action as an anticholinergic agent. It works by blocking the effects of acetylcholine on the muscarinic receptors in the heart, thereby inhibiting the parasympathetic nervous system's influence. This results in an increased heart rate, particularly in situations where the heart rate is abnormally low, such as in bradycardia. The inhibition of AV conduction can also occur because acetylcholine typically facilitates conduction through the AV node; thus, By blocking its action, Atropine can speed up conduction through the heart's conduction system. This is essential in clinical scenarios where rapid restoration of heart rate and effective cardiac output are necessary.