What do hormones primarily function as in the body?

Hormones primarily function as chemical messengers in the body. They are produced by various glands and secreted directly into the bloodstream, where they travel to target organs or tissues to elicit specific physiological responses. This function is critical for regulating a wide range of bodily processes, including metabolism, growth and development, immune responses, and mood. Hormones can coordinate complex processes by binding to specific receptors on cells, initiating a signal transduction pathway that alters cellular activity.

In contrast, receptors for nerve impulses are specialized proteins that detect neurotransmitters, not hormones. Storage molecules for energy, such as glycogen and fats, have a different role focused on energy reserves rather than signaling. While structural components of cells, such as proteins and lipids, provide form and function to cellular structures, they do not engage in the signaling processes characteristic of hormones. Thus, the role of hormones as chemical messengers is unique and essential for maintaining homeostasis and regulating bodily functions.