Hormones are chemical messengers that regulate various physiological processes in the body. They are produced by the endocrine glands and transported through the bloodstream to target cells, where they bind to specific receptors and trigger a response. Hormones play a role in growth and development, metabolism, reproduction, stress response, and many other functions. Examples of hormones include insulin, which regulates blood sugar levels, and estrogen and testosterone, which are involved in sexual development and function.