Small Intestine and Large Intestine

The intestine is a segment of the digestive system that lies between the stomach and the rectum. The main function of this structure is to carry out the absorption of the different nutrients and the Water contained in the food.

Its first part is the longest, it is known as the small intestine. The final part, which is macroscopically thicker, and has a wall with different characteristics, for these reasons it is called the large intestine.

Small intestine

It is tube-shaped, with a diameter about 3 cm and a length close to 7 meters. It consists of three parts: duodenum, jejunum, and ileum.

Duodenum. It is the initial portion of the intestinal tube, it is located below the stomach, it is 25 cm long and consists of four segments. The food reaches the duodenum after leaving the stomach through the pylorus, at this level the ducts coming from the gallbladder open and the pancreas, which carry secretions known as digestive juices in which there are various enzymes necessary to carry out the digestion of fats and sugars.

Jejunum-ileum. It is located below the duodenum, in this segment it is arranged in a "U" shape, giving rise to the so-called intestinal loops. The jejunoileon is attached to the back wall of the abdomen by a membrane known as the mesentery. It is rich in structures called intestinal villi which have the function of increasing the intestinal surface that comes into contact with digested food, this favors the absorption process of the nutrients.

Large intestine

It corresponds to the last portion of the intestine, reaches 1.5 meters in length with a diameter of 7 to 8 cm. It has four parts: cecum, colon, sigmoid, and rectum.

Blind. It is the first part, it is located in the lower right region of the abdomen, there is the hole through which the appendix empties.

Colon. It is the longest portion of the large intestine and is divided into three parts, identifying the ascending colon located on the side right the abdomen, the transverse colon located in front of the stomach, and the descending colon located on the left side of the abdomen.

Sigmoid. Corresponds to a fragment free loop that is located in the lower left part of the abdomen and continues with the rectum.

Right. It is the final part, they have a larger diameter and constitutes a reservoir where feces accumulate until the moment they are expelled out through the anus.

This intestinal segment's main function is to carry out the absorption of the water that remains as a remnant of food after being absorbed the various nutrients at the level of the jejunoileon.

The final residue contained within the colon and sigmoid is converted into feces, a waste product that must be evacuated to the outside.

Photo: Fotolia - Christos Georghiou