The glomerulus is the basic structural and functional unit of the kidney, which is composed of capillary endothelial cells, glomerular basement membrane, and epithelial cells to form the filtration barrier. The glomerular basement membrane is composed of three layers of loose tissue, and the glomerular thylakoid zone is composed of thylakoid cells and thylakoid stroma, which play a supporting role to ensure the smooth flow of glomerular capillaries and regulate glomerular hemodynamics as well as filtration function. The paraglomerular apparatus is composed of dense patches of paraglomerular cells and extraglomerular thylakoid cells, which are cells with secretory function and mainly secrete renin.