This kidney bears fhe finely granular surface typical of people who have had high blood pressure for a long time. As individual nephrons are replaced by scar tissue, the contraction of the scar produces the "sandpaper kidney" effect.
This medium-sized renal artery has marked fibrous thickening of its intima. This is both the result of the high blood pressure, and part of the vicious cycle of glomerular ischemia that perpetuates it.