The endocrine system regulates many important bodily functions through glands like the pituitary, thyroid, parathyroid, adrenal and gonads that secrete hormones. The pituitary gland, located in the brain, is called the "master gland" as it controls the functions of other glands by producing hormones like prolactin, ACTH, TSH, FSH, and LH. Key endocrine glands include the thyroid, which regulates metabolism through thyroid hormones, the adrenals which release hormones like adrenaline during the stress response, and the gonads which produce sex hormones that influence growth, development and reproductive cycles.