For the intestinal structure, see Vasa recta (intestines)

Vasa recta (intestines)

For the kidney structure, see vasa rectaVasa recta are straight arteries coming off from arcades in the mesentery of the jejunum and ileum, and heading toward the intestines....

In the blood supply of the kidney

Renal circulation

The renal circulation receives around 20% of the cardiac output. It branches from the abdominal aorta and returns blood to the ascending vena cava. It is the blood supply to the kidney, and contains many specialized blood vessels.-Circulation:...

, the vasa recta renis (or straight arteries of kidney, or straight arterioles of kidney) form a series of straight capillaries (recta is from the Latin for "straight") in the medulla

Renal medulla

The renal medulla is the innermost part of the kidney. 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...

. They lie parallel to the loop of Henle.

These vessels branch off the efferent arteriole

Efferent arteriole

The efferent arterioles are blood vessels that are part of the urinary tract of organisms. The efferent arterioles form from a convergence of the capillaries of the glomerulus...

s of juxtamedullary nephron

Juxtamedullary nephron

A juxtamedullary nephron is a type of nephron, found only in birds and mammals and not in other vertebrates. The "medullary" is referring to the renal medulla, while the "juxta", , refers to the relative position of the renal corpuscle, which in these nephrons is near the medulla...

s (those nephron

Nephron

The renal tubule is the portion of the nephron containing the tubular fluid filtered through the glomerulus. After passing through the renal tubule, the filtrate continues to the collecting duct system, which is not part of the nephron....

s closest to the medulla), enter the medulla, and surround the loop of Henle

Loop of Henle

In the kidney, the loop of Henle is the portion of a nephron that leads from the proximal convoluted tubule to the distal convoluted tubule. Named after its discoverer F. G. J...

.

Histology

On a slide, vasa recta can be distinguished from the tubules of the loop of Henle

Loop of Henle

In the kidney, the loop of Henle is the portion of a nephron that leads from the proximal convoluted tubule to the distal convoluted tubule. Named after its discoverer F. G. J...

 by the presence of blood.

Function

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

Countercurrent exchange

Countercurrent exchange is a mechanism occurring in nature and mimicked in industry and engineering, in which there is a crossover of some property, usually heat or some component, between two flowing bodies flowing in opposite directions to each other. The flowing bodies can be liquids, gases, or...

 that prevent washout of the concentration gradients established in the renal medulla.

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

Urine

Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...

.

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

According to Terminologia Anatomica

Terminologia Anatomica

Terminologia Anatomica is the international standard on human anatomic terminology. It was developed by the Federative Committee on Anatomical Terminology and the International Federation of Associations of Anatomists and was released in 1998. It supersedes the previous standard, Nomina...

 , the term "vasa recta renis" is an alternate name for "arteriolae rectae renis", and a separate term, venulae rectae renis

Straight venules of kidney

The straight venules of kidney are branches from the plexuses at the apices of the medullary pyramids, formed by the terminations of the arteriae rectae....

, is used to identify the venous portion.

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

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

• vasa recta (intestines)
  Vasa recta (intestines)
  For the kidney structure, see vasa rectaVasa recta are straight arteries coming off from arcades in the mesentery of the jejunum and ileum, and heading toward the intestines....
  
   (in the ileum
  Ileum
  The ileum is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine may be used instead of ileum.The ileum follows the duodenum...
  
   and jejunum
  Jejunum
  The jejunum is the middle section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms middle intestine or mid-gut may be used instead of jejunum.The jejunum lies between the duodenum...
  
  )
• the straight portion of the seminiferous tubule, though this is usually called the tubuli recti
  Tubuli seminiferi recti
  The tubuli seminiferi recti is a structure in the testicle connecting the convoluted region of the seminiferous tubule to the rete testis, although the tubuli recti has a different appearance distinguishing it from these two structures.They enter the fibrous tissue of the mediastinum,...
  
  .

Pathology

The slow blood flow in vasa recta makes them a likely location of thrombosis

Thrombosis

Thrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel is injured, the body uses platelets and fibrin to form a blood clot to prevent blood loss...

 in hypercoagulable states, or tissue loss due to erythrocyte sickling in sickle cell disease. Ischemia

Ischemia

In medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...

 that results may lead to renal papillary necrosis

Renal papillary necrosis

Renal papillary necrosis is a form of nephropathy involving the necrosis of the renal papilla, which is supplied by the vasa recta.-Causes:Analgesic nephropathy is a cause of renal papillary necrosis. The damage is cumulative and most patients of renal papillary necrosis would have ingested at...

.

External links

• UMLS