Cells of the Kidney

The kidney’s functions in filtration, ion homeostasis, and blood pressure control rely on multiple cell types and anatomical structures. Blood and urine are separated by the filtration barrier that consists of the glomerular basement membrane sandwiched between glomerular endothelial cells contacting the blood and podocytes contacting the urinary filtrate. Parietal epithelial cells enclose Bowman’s capsule which directs the filtrate into the nephron tubule. Ionic composition and concentration of the urine are regulated by tubule epithelial cells. The macula densa is a region of the tubule epithelium which contacts the glomerular tuft capillaries. This arrangement provides tubule-glomerular feedback and enables the renal corpuscle to fine tune ion homeostasis, acid-base balance, and blood pressure.