A digital computer model of the renal medullary countercurrent system. I

✍ Scribed by Toshiyuji Furukawa; Seiichi Takasugi; Michitoshi Inoue; Hiroshi Inada; Fumihiko Kajiya; Hiroshi Abe

• Publisher: Elsevier Science
• Year: 1974
• Tongue: English
• Weight: 802 KB
• Volume: 7
• Category: Article
• ISSN: 0010-4809
• DOI: 10.1016/0010-4809(74)90003-2

✦ Synopsis

A mathematical model of the renal medulla was made, integrating structural and functional concepts into a unified understanding of the mechanisms involved. The medulla was assumed to have vasa recta, the loops of Henle, collecting tubules and interstitium. Numerical studies were carried out to simulate the movement of water, sodium and urea in nonsteady states on an assumption that sodium pump exists along the loops of Henle and collecting tubules, and that no active transport of urea exists in the kidney.

The model yielded piecewise continuous curves for volume flow rate, and sodium and urea concentration profiles which reasonably agree with available data along the consecutive segments. It was shown that the osmolality gradient could not be reproduced reasonably well without taking the presence of sodium pump along the thin loops of Henle. It was also shown that the concentrationgradient for urea could become steeper than that of sodium without resulting in its active transport.