Uberon related term : medullary pyramids; renal marrow;
Uberon Structure note : The renal medulla is split up into a number of sections, known as the renal pyramids.
Blood enters into the kidney via the renal artery, which then splits up to form the
arcuate arterioles. The arcuate arterioles each in turn branch into interlobular arterioles,
which finally reach the glomeruli. At the glomerulus the blood reaches a highly disfavourable
pressure gradient and a large exchange surface area, which forces the serum portion
of the blood out of the vessel into the renal tubules. Flow continues through the
renal tubules, including the proximal tubule, the Loop of Henle, and finally leaves
the kidney by means of the collecting duct, leading to the renal ureter. The renal
medulla contains the structures of the nephrons responsible for maintaining the salt
and water balance of the blood. The renal medulla is hypertonic to the filtrate in
the nephron and aids in the reabsorption of water;