HSC Biology Practice Exam

Chemical messengers produced by the endocrine glands that affect other tissues are known as hormones. Hormones are secreted directly into the bloodstream and travel to various organs and tissues, where they elicit specific physiological responses. They play a critical role in regulating numerous bodily functions, including metabolism, growth and development, tissue function, and mood.

While neurotransmitters are involved in signaling between neurons, and enzymes facilitate biochemical reactions, they do not primarily serve the role of long-distance signaling like hormones do. Cytokines, on the other hand, are involved in immune responses and communication between cells, but they are not classified specifically as hormones produced by endocrine glands. Thus, hormones are the key chemical messengers that carry information throughout the body, influencing a wide array of biological processes.