Endocrine glands mainly include pituitary gland, thyroid gland, parathyroid gland, pancreatic islets, adrenal glands, pineal gland, thymus gland, gonads, etc.: a. Pituitary gland can secrete a variety of hormones and influence the secretion of other glands through hypothalamic-pituitary-thyroid axis, hypothalamic-pituitary-gonadal axis and hypothalamic-pituitary-adrenal axis; b. Thyroid gland mainly secretes thyroid hormones, which can promote human growth and development and promote the development of the nervous system The parathyroid glands, which mainly secrete parathyroid hormones, are used to regulate calcium and phosphorus metabolism; iv. The pancreatic islets, which secrete insulin from pancreatic beta cells and glucagon from pancreatic alpha cells, and insulin and glucagon are important hormones for regulating blood sugar; v. The adrenal glands, which secrete glucocorticoids and salt corticoids, regulate the body’s sugar and water and salt metabolism, and play an important role in stress; vi. The gonads, which mainly secrete gonadal hormones, promote the development of sexual organs, and affect secondary sexual characteristics; vii. the pineal gland is involved in the formation of the body’s biological clock, and the thymus gland is mainly involved in the body’s immune response.