Vasa recta

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Artery: Vasa recta
Kidney nephron.png
A nephron, the vasa recta is labelled arteria recta
Latin arteriolae rectae renis
Gray's p.1224
Source Arcuate arteries of the kidney, efferent arteriole
Branches Straight venules of kidney, arcuate vein
Dorlands
/Elsevier
Vasa recta renis
For the intestinal structure, see Vasa recta (intestines)

In the blood supply of the kidney, the vasa recta renis (or straight arteries of kidney, or straight arterioles of kidney) are a series of straight capillaries in the medulla (Latin: vasa, "vessels"; recta, "straight"). They lie parallel to the loop of Henle.

These vessels branch off the efferent arterioles of juxtamedullary nephrons (those nephrons closest to the medulla), enter the medulla, and surround the loop of Henle.

Histology[edit]

On a slide, vasa recta can be distinguished from the tubules of the loop of Henle by the presence of blood.[1]

Function[edit]

Each of the vasa recta has a hairpin turn in the medulla and carries blood at a very slow rate, two factors crucial in the maintenance of countercurrent exchange that prevent washout of the concentration gradients established in the renal medulla.[2]

The maintenance of this concentration gradient is one of the components responsible for the kidney's ability to produce concentrated urine.

On the descending portion of the vasa recta, NaCl and urea are reabsorbed into the blood, while water is secreted. On the ascending portion of the vasa recta, NaCl and urea are secreted into the interstitium, while water is reabsorbed.

Nomenclature[edit]

According to Terminologia Anatomica, the term "vasa recta renis" is an alternate name for "arteriolae rectae renis", and a separate term, venulae rectae renis, is used to identify the venous portion.

However, other sources consider "vasa recta renis" to refer to both the arterial and venous portions.[3]

The "renis" is often omitted, but there do exist two other structures with the same name:

Pathology[edit]

The slow blood flow in vasa recta makes them a likely location of thrombosis in hypercoagulable states, or tissue loss[5] due to erythrocyte sickling in sickle cell disease. Ischemia that results may lead to renal papillary necrosis.

References[edit]

  1. ^ Histology image:15802loa from Vaughan, Deborah (2002). A Learning System in Histology: CD-ROM and Guide. Oxford University Press. ISBN 978-0195151732. 
  2. ^ Physiology at MCG 7/7ch08/7ch08p07
  3. ^ Histology image:15804loa from Vaughan, Deborah (2002). A Learning System in Histology: CD-ROM and Guide. Oxford University Press. ISBN 978-0195151732. 
  4. ^ jejunumileum at The Anatomy Lesson by Wesley Norman (Georgetown University)
  5. ^ ter Maaten JC, Serné EH, van Eps WS, ter Wee PM, Donker AJ, Gans RO (March 2000). "Effects of insulin and atrial natriuretic peptide on renal tubular sodium handling in sickle cell disease". Am. J. Physiol. Renal Physiol. 278 (3): F499–505. PMID 10710555. 

External links[edit]