small intestine anatomy.

The small intestine is an essential part of the human digestive system, located between the stomach and the large intestine. It is where most of the digestion and nutrient absorption from food takes place. The small intestine is approximately 6–7 meters long in adults and is divided into three main sections: the duodenum, jejunum, and ileum.

Duodenum (the first section): Receives food mixed with digestive juices from the stomach, bile from the liver, and digestive enzymes from the pancreas, which help break down food.
Jejunum (the middle section): Responsible for absorbing nutrients, including proteins, carbohydrates, and vitamins.
Ileum (the final section): Continues the absorption process, particularly of vitamin B12 and bile salts, before passing the remaining food material to the large intestine.
The small intestine has a mucosal lining composed of folds, villi, and microvilli, which increase the surface area for maximum nutrient absorption. This organ plays a vital role in maintaining health and providing energy for the body.