The endocrine system is made up of several glands that secrete hormones directly into the bloodstream to regulate growth, metabolism, reproduction, and other processes. The major glands include the pituitary gland, thyroid gland, pancreas, adrenal glands, hypothalamus, parathyroid glands, pineal gland, and gonads. The pituitary gland is called the "master gland" as it controls the function of other glands. The thyroid gland regulates metabolism and organ function by secreting thyroxine and triiodothyronine. The pancreas regulates blood sugar and digestion by producing insulin and glucagon.