The thyroid is a butterfly-shaped gland located in the front of the neck, just below the Adam's apple. It plays a crucial role in regulating the body's metabolism by producing hormones, primarily thyroxine (T4) and triiodothyronine (T3). These hormones help control how the body uses energy, affecting various functions such as heart rate, temperature, and weight. When the thyroid is not functioning properly, it can lead to conditions like hypothyroidism (underactive thyroid) or hyperthyroidism (overactive thyroid). Symptoms of hypothyroidism may include fatigue and weight gain, while hyperthyroidism can cause weight loss and increased heart rate. Regular check-ups can help monitor thyroid health.