Which description best captures the role of hormones in the body?

• A. Internal secretions that regulate metabolism, growth, reproduction and development, and regulate water and electrolyte balance and blood pressure.
• B. They act as enzymes in digestion.
• C. They form structural components of cells.
• D. They primarily store energy as fat.

Answer: (A)

Hormones are chemical messengers released into the bloodstream by endocrine glands, traveling to distant target tissues to regulate function. They influence metabolism, growth, reproduction and development, and help maintain water and electrolyte balance and blood pressure. This description captures how hormones coordinate many body processes and maintain homeostasis, rather than acting as digestive enzymes, forming structural components of cells, or storing energy themselves. For example, hormones like insulin and glucagon manage energy use and storage, antidiuretic hormone helps regulate water balance, thyroid hormones adjust metabolic rate, and aldosterone influences electrolyte balance and blood pressure. In contrast, enzymes in digestion catalyze reactions locally, cellular structures are built from proteins and lipids, and energy storage is primarily handled by adipose tissue.