Final answer:
The ANS has two divisions, the sympathetic and the parasympathetic, which use norepinephrine and acetylcholine as neurotransmitters, respectively. These neurotransmitters bind to adrenergic and muscarinic receptors, respectively, which are located on various target cells throughout the body.
Step-by-step explanation:
Autonomic Nervous System Divisions and Neurotransmitters
The autonomic nervous system (ANS) consists of two main divisions: the sympathetic and parasympathetic nervous systems. The sympathetic system is often associated with the 'fight or flight' response, while the parasympathetic system is associated with 'rest and digest' functions.
Each division uses different neurotransmitters to communicate with target cells. The postganglionic sympathetic fibers predominantly release norepinephrine, except for a minor exception with the sympathetic pathway to the sweat glands, which uses acetylcholine (ACh). On the other hand, postganglionic parasympathetic fibers release ACh. These neurotransmitters bind to their respective receptors on the target cells.
Norepinephrine released by the sympathetic fibers binds to adrenergic receptors, which are primarily located on the target cells of the sympathetic nervous system. In contrast, acetylcholine released by the parasympathetic fibers binds to muscarinic receptors, found on the target cells of the parasympathetic nervous system.
Receptors and Their Locations
Adrenergic receptors are found throughout the body in various tissues and organs responsive to sympathetic output, such as the heart, blood vessels, and lungs. Muscarinic receptors are located in organs such as the gastrointestinal tract, bladder, and eyes, which are targeted by parasympathetic neurotransmitters.