The endocrine system consists of many glands, such as the pituitary gland, thyroid, parathyroid, adrenal glands, gonads, pancreatic islets, etc. In addition, there are many endocrine glands, tissues, and cells in the cardiovascular and gastrointestinal tissues. Endocrine glands, tissues and cells secrete endocrine hormones such as thyroid hormone, parathyroid hormone, adrenaline, cortisol and other hormones to maintain the stability of the internal environment. If the glands become hyper- or hypogonadal, endocrine disorders will result. The thyroid gland is one of the endocrine glands, and thyroid disorders fall into the category of endocrine disorders.