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Large intestine

life science Maturity 9-11 Next article →

The large intestine is the final part of the digestive system in tetrapods.

Blausen 0604 LargeIntestine2
Blausen 0604 LargeIntestine2

It is a very important tube that helps the body manage waste. In humans, this part of the body is about one-fifth of the whole digestive tract.

3DPX-002736 Large intestine Nevit Dilmen
3DPX-002736 Large intestine Nevit Dilmen

The large intestine is made of several different parts working together. These parts include the cecum, the colon, the rectum, and the anal canal. Many people use the word "colon" to mean the whole large intestine. However, the colon is actually just the longest section of the entire system.

This system works by moving waste through a specific path.

Diameters of the large intestine
Diameters of the large intestine

First, waste moves from the small intestine through a valve called the ileocecal valve. It enters the cecum and then moves into the ascending colon. The waste is pumped upward by a movement called peristalsis. Next, it travels across the body through the transverse colon. The waste then moves down the descending colon and through the S-shaped sigmoid colon. Finally, the waste is stored in the rectum before it leaves the body.

While the waste moves, the body performs a very important job. The colon extracts water and salt from the solid waste. This process helps the body recycle these useful materials.

Colonic crypts within four tissue sections
Colonic crypts within four tissue sections

Inside the colon, tiny living things called microbiota live. These microbes perform fermentation on material that the body did not absorb. The walls of the colon are lined with tiny tubes called colonic crypts. These microscopic glands are shaped like thick-walled test tubes. This helps the colon manage the waste effectively.

There are many specific measurements for the parts of the colon. In healthy people, the cecum is the widest part at almost 9 cm. The transverse colon is narrower, averaging less than 6 cm in diameter. In adult humans, the colon length varies by sex. For males, the average length is between 80 and 313 cm. For females, the average length is about 155 cm. The rectum is the last section and is about 12 cm long.

Large intestine histology
Large intestine histology

These numbers help doctors understand how the body is working.

Understanding the large intestine helps us see how the body stays healthy. Just like a recycling center, the colon saves water so it is not wasted. The different sections, like the sigmoid colon, use muscles to create pressure. This pressure moves the waste toward the end of the path. Some people have a "redundant colon," which means it has extra loops. This can make the colon up to five meters longer than normal. Even with these differences, the system works hard to keep the body running smoothly.

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🖼️ Images & Media (6)
File:Blausen 0604 LargeIntestine2.png
Blausen 0604 LargeIntestine2.png
File:Diameters of the large intestine.svg
Diameters of the large intestine.svg
3DPX-002736 Large intestine Nevit Dilmen.stl
File:Colonic crypts within four tissue sections.jpg
Colonic crypts within four tissue sections.jpg
File:Large intestine histology.jpg
Large intestine histology.jpg
File:Colonoscopy splenic flexure.jpg
Colonoscopy splenic flexure.jpg
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