Which statement best describes the function of hormones?

• A. Hormones regulate metabolism, growth, reproduction and development, regulate water and electrolyte balance and blood pressure.
• B. They regulate muscle contraction only.
• C. They transmit electrical impulses between neurons.
• D. They provide structural support to tissues.

Answer: (C)

Hormones act as chemical messengers released into the bloodstream to coordinate and regulate activities in distant targets. They influence metabolism, growth, reproduction, and development, and they help maintain water and electrolyte balance and blood pressure. This broad regulatory role best fits the function of hormones, since they coordinate many body systems over longer timescales. They are not primarily responsible for triggering muscle contraction on their own, nor do they transmit electrical impulses between neurons—that nervous system signaling relies on neurons and neurotransmitters. They also don’t provide structural support to tissues, which is the job of connective tissues. Examples show the range: insulin and glucagon regulate metabolism; growth and thyroid hormones influence growth, development, and metabolic rate; antidiuretic hormone and aldosterone help control water balance and blood pressure.