Which term is often associated with chemical signals in the body?

Hormones are chemical signals produced by various glands in the endocrine system that travel through the bloodstream to target organs and tissues, where they regulate physiological processes such as metabolism, growth, and mood. They play a crucial role in maintaining homeostasis within the body by enabling communication and coordination between different physiological systems. Hormones have specific receptors that they bind to on target cells, initiating a response that is necessary for the functioning of organs and systems.

Other terms listed, while related, describe different functions or types of chemical substances. Vitamins are essential nutrients required in small amounts for various bodily functions but do not serve as chemical signals. Enzymes are proteins that catalyze biochemical reactions and facilitate metabolic processes, not signaling. Neurotransmitters are chemical messengers in the nervous system that transmit signals between nerve cells (neurons), but they are distinct from hormones, which operate through the bloodstream and have wider systemic effects.