<Tr> <Th> FMA </Th> <Td> 258870 74268, 258870 </Td> </Tr> <Tr> <Td_colspan="2"> Anatomical terminology (edit on Wikidata) </Td> </Tr> <P> Renal pyramids (or malpighian pyramids or Malpighi's pyramids named after Marcello Malpighi, a seventeenth - century anatomist) are cone - shaped tissues of the kidney . In humans, the renal medulla is made up of 10 to 18 of these conical subdivisions . The broad base of each pyramid faces the renal cortex, and its apex, or papilla, points internally towards the pelvis . The pyramids appear striped because they are formed by straight parallel segments of nephrons and collecting ducts . The base of each pyramid originates at the corticomedullary border and the apex terminates in a papilla, which lies within a minor calyx, made of parallel bundles of urine collecting tubules . </P> <Ul> <Li> <P> Frontal section through the kidney </P> </Li> </Ul>

Why do renal pyramids have a striped appearance