AEMCA Practice Exam

Acetylcholine is primarily responsible for parasympathetic activity within the autonomic nervous system. It acts as the primary neurotransmitter released by the postganglionic neurons of the parasympathetic division. When acetylcholine binds to its receptors on target organs, it facilitates various physiological responses associated with the "rest and digest" state, such as decreased heart rate, enhanced digestion, and increased glandular activity. This neurotransmitter plays a critical role in promoting restorative and maintenance functions in the body, contrasting with the actions of other neurotransmitters that may stimulate different sympathetic responses. Understanding the role of acetylcholine is essential for grasping how the parasympathetic nervous system operates to maintain homeostasis and promote relaxation after stress or physical activity.