Final answer:
The nervous system communicates with target organs through neurotransmitters, which act on specific receptors in target cells.
Step-by-step explanation:
The nervous system affects target organs through the release of chemicals known as neurotransmitters. These chemical messengers are crucial for the transmission of signals from the nervous system to various target cells, where they interact with specific protein receptors in the cell membranes. To add, the endocrine system is another system that is activated by chemical messengers, specifically hormones. These substances maintain homeostasis by ensuring the timing and coordination of physiological events, as hormones are secreted into the bloodstream and affect cells that contain corresponding receptors.
Although both neurotransmitters and hormones are chemical messengers, neurotransmitters act locally and quickly at synapses, while hormones act globally and over a longer time frame. Chemical signaling in the autonomic nervous system can occur through neurotransmitters such as acetylcholine and norepinephrine, where they bind to cholinergic or adrenergic receptors respectively. This coordinated communication between the nervous and endocrine systems is essential for maintaining homeostasis in the body.