Vasa recta (intestines)

The vasa recta of the intestines, also known as straight arteries, are a series of long, straight blood vessels that are part of the microcirculation system within the intestines. They are responsible for supplying blood to the intestinal villi, the small, finger-like projections that line the inner wall of the intestines and increase their absorptive surface area.

Structure

The vasa recta originate from the arterioles that branch off the superior mesenteric artery and inferior mesenteric artery, which supply blood to the small and large intestines, respectively. They descend into the submucosa layer of the intestinal wall, where they branch into a network of capillaries that surround the intestinal villi.

Diagram of the arterial supply to the intestines, showing the vasa recta and their branches.

Function

The primary function of the vasa recta is to supply oxygenated blood to the intestinal villi. This is crucial for the absorption of nutrients from the food we eat, as the villi contain enterocytes, specialized cells that absorb nutrients from the intestinal lumen into the bloodstream.

In addition to supplying blood, the vasa recta also play a role in the countercurrent exchange mechanism, which helps to maintain a concentration gradient in the intestines. This allows for the efficient absorption of water and electrolytes from the intestinal lumen.

Clinical significance

Disruption of the vasa recta can lead to various intestinal disorders. For example, ischemic colitis can occur when there is insufficient blood flow to the colon, often due to blockage of the vasa recta. This can cause symptoms such as abdominal pain, bloody diarrhea, and in severe cases, gangrene of the intestinal wall.

Histopathology of ischemic colitis, showing necrosis of the intestinal wall due to insufficient blood supply.

See also

• Microcirculation
• Superior mesenteric artery
• Inferior mesenteric artery
• Intestinal villi
• Enterocytes
• Ischemic colitis

References

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