The endocrine system regulates body functions through the synthesis and release of hormones from endocrine glands. The hypothalamus links the nervous and endocrine systems by stimulating or inhibiting hormone release from the pituitary gland. The pituitary gland, known as the "master gland", regulates other endocrine glands and organs by producing hormones that signal the release of other hormones. Key endocrine glands include the thyroid, adrenals, pancreas, ovaries/testes, and parathyroids, each producing hormones that regulate processes like metabolism, stress response, growth, and reproduction.