Measuring around 15 feet, your intestines break down and absorb essential nutrients from food and drinks, which then enter your bloodstream.

An illustration showing the small intestines as well as the large intestines, with labels for the different areas, like the small intestine, ascending colon, transverse colon, descending colon, sigmoid colon, appendix, cecum and anal canal. Share on Pinterest

Your intestines are a crucial part of your digestive system. It’s where nutrients from food are broken down and absorbed into your bloodstream.

Your small intestine runs from your stomach to your large intestine. It continues the process of digestion that started in your stomach.

The small intestine absorbs nutrients and water from digested food. In fact, 90% of food absorption happens here. Whatever is left over then passes into your large intestine.

Your small intestine is divided into 3 parts:

  • Duodenum: In the duodenum, various enzymes, including those from the pancreas and liver, further break down and absorb partially digested nutrients from your stomach.
  • Jejunum: Further digestion and absorption happen here.
  • Ileum: Here, any remaining nutrients are absorbed. The ileum connects to the cecum, the first part of your large intestine.

Certain health conditions can affect the small intestine, including:

The length of the small intestine can vary between about 10 feet (3 meters) and over 16 feet (5 meters). For comparison, a standard basketball hoop is 10 feet tall.

Different sections of the small intestine differ in length. The ileum is the longest part, while the duodenum is the shortest.

Since it’s so long, you may wonder why the small intestine is called “small” in the first place. This term actually refers to the diameter of the small intestine, which is about 1 inch (around 2.5 cm).

Despite its small diameter, the small intestine has a very high surface area. That’s because its walls are actually covered in folds and hair-like projections. This increased surface area allows for more absorption of nutrients and water.

Your large intestine runs from your small intestine to your anus.

It absorbs water and electrolytes from the food you’ve eaten. Any remaining food that isn’t absorbed in the large intestine becomes stool.

Additionally, bacteria found in the large intestine can help to further break down any remaining nutrients. Vitamins such as vitamin K are also produced in the large intestine.

Like the small intestine, the large intestine has several different parts:

  • Cecum: The cecum receives food from the small intestine. Water and electrolytes are absorbed here.
  • Colon: The colon has several parts — the ascending colon, the transverse colon, the descending colon, and the sigmoid colon. Like the cecum, it absorbs water and electrolytes.
  • Rectum: Undigested food material moves from the colon to the rectum. Here, stool is held until it can be eliminated from the body.
  • Anus: Stool passes through your anus and out of your body when you have a bowel movement.

Some specific health conditions can affect the large intestine, including:

The large intestine is about 5 feet (1.5 meters) long. If you stretched out your large intestine, it would be about as long as the width of a queen-size bed.

The colon is the longest portion of your large intestine. The other parts — the cecum, rectum, and anus — are all much shorter, only a few inches in length at the most.

The large intestine also has a larger diameter than the small intestine. It’s about 3 inches (around 7.6 centimeters) wide.

Together, your small and large intestines are about 15 feet or more in length.

Your intestines have the very important job of helping to break down and absorb nutrients from what you eat and drink. Once these nutrients are absorbed, they can be delivered via the bloodstream to the rest of your body.