Glomerulonephritis. Light micrograph of a section through a kidney affected by membranoproliferative glomerulonephritis (MPGN). Glomerulonephritis is the inflammation either of the glomeruli or small blood vessels in the kidneys. MPGN is a type of glomerulonephritis caused by deposits in the kidney mesangium tissue and basement membrane thickening, which damages the glomeruli and impairs the function of the kidney. Magnification: x1100, when printed 10 centimetres wide.