Function of Intestines in the Cardiovascular System

The intestines are not part of the cardiovascular system but contribute to its function by digesting nutrients from food for use in all the cells of the body. The intestines are divided into two major parts, the small intestine and the large intestine.

The Small Intestine

The small intestine lies coiled in the abdominal cavity. Stretched to its full length, it's 20-23 feet long. While the small intestine is several times longer than the large intestine, it gets its name because it is smaller in diameter than the large intestine. There are three sections to the small intestines (duodenum, jejunum and ileum) and each section serves a specific purpose.

The first section is the duodenum, which connects directly to the stomach and is where all the food we eat is prepared for further digestion. The second section is the jejunum, where the actual digestion takes place. The final section is the Ileum, where nutrient absorption occurs.

The inside walls of the small intestines have wrinkles called rugae. The rugae then have structures called villi, and the villi have even smaller structures called microvilli. All of these structures increase the surface area of the intestines. So while the small intestine is very narrow, its length combined with the rugae, villi and microvilli give it a surface area roughly equivalent to a tennis court. This high surface area provides for optimal nutrient absorption.

The Large Intestine

The large intestine wraps around the small intestine like a picture frame. It's 5 feet long and is divided into four sections: the cecum, colon, rectum and anal canal.

The caecum connects to the small intestine at the Ileum and this is where the final product enters the large intestine. The colon is the longest part of the large intestine and is divided into four sections: the ascending, transverse, descending and sigmoid colon. The rectum is where the final waste products are prepared for removal, and the anal canal is where the waste actually leaves the body.

The Function of the Small Intestine

A look at how the intestinal tract works helps to understand how the small intestine functions in the cardiovascular system. When food is ingested, it first goes to the stomach where it is churned into a substance called chyme. The chyme then moves from the stomach to the duodenum of the small intestine. In the duodenum, the pancreas squirts digestive enzymes like lipase, protease and amylase to break the chyme down into its smallest parts. The lipase breaks fats down into fatty acids, the amylase breaks carbohydrates down into starches, and the protease breaks proteins down into amino acids.

From the duodenum, the chyme then moves to the jejunum and Ileum where the enzymes continue to break it down and the villi and microvilli absorb the nutrients into the bloodstream. It's at the level of the villi and microvilli where the cardiovascular function of the small intestine becomes clear. Each villus has a blood supply in the form of capillaries. Capillaries are tiny blood vessels with very thin walls that allow nutrients, gases and other small particles to pass in and out of the bloodstream. Once the nutrients enter the bloodstream, they are carried to the cells by a complex network of arteries and veins.

The Function of the Large Intestine

The large intestines also serve a small function in the cardiovascular system. Once the nutrients are absorbed from the chyme, it's moved to the large intestine where water and any minerals are removed and waste is solidified into fecal matter. The water and minerals are put back into the bloodstream, which helps maintain blood volume and electrolyte balance.

Conclusion

The intestines play two minor roles in the cardiovascular system. They transform the food we eat into a form that our bodies can use, then transfer those nutrients into the blood. They also help maintain the water and mineral balance in our blood. A healthy intestinal tract is essential to our health and well-being, and proper diet and exercise is the best way to ensure the proper function of our intestinal tract.