The organ responsible for regulating hormones and metabolism in the body is the thyroid gland. This butterfly-shaped gland, located in the neck, produces hormones such as thyroxine (T4) and triiodothyronine (T3), which play crucial roles in controlling the body's metabolic rate, heart rate, and overall energy levels. The thyroid gland helps regulate essential bodily functions by providing the necessary hormones that influence growth, development, and metabolism. Proper functioning of the thyroid is vital for maintaining overall health and homeostasis in the body.