Hyperplasia is a pathological term that refers to the phenomenon of increased number of cells in tissues or organs due to active cell division, which can be divided into physiological and pathological hyperplasia according to its nature.
1. Physiological hyperplasia: the oxygen content of the air in the plateau area is low, and the bone marrow erythrocyte precursor cells and peripheral blood erythrocytes are increased by compensation; the proliferation of endometrial glands during the menstrual cycle; and the proliferation of lobular adenoepithelium in the breasts of normally developing women during puberty.
2. Pathological hyperplasia: scarring hyperplasia of fibroblasts and capillary endothelial cells during the healing process after tissue injury; hyperplasia of inflammatory cells and tumor cells; hyperplasia of female breast tissue caused by excessive secretion of estrogen; prostatic hyperplasia caused by old age or excessive secretion of androgen.