dünndarmn

Dünndarm is the German word for small intestine. The small intestine is a long, coiled tube in the digestive system that extends from the stomach to the large intestine. It is the primary site for the digestion and absorption of nutrients from food. The small intestine is divided into three main sections: the duodenum, the jejunum, and the ileum.

The duodenum is the first and shortest section, receiving partially digested food from the stomach and bile from the liver and gallbladder, as well as digestive enzymes from the pancreas. These substances help to break down carbohydrates, proteins, and fats. The jejunum is the middle section, where most of the nutrient absorption takes place. Its inner lining is covered with villi and microvilli, which are tiny finger-like projections that significantly increase the surface area available for absorption. The ileum is the final section, responsible for absorbing vitamin B12, bile salts, and any remaining nutrients that were not absorbed in the jejunum.

The walls of the small intestine are muscular and contract to mix food with digestive juices and propel it forward through a process called peristalsis. The lining of the small intestine secretes enzymes that further break down food particles into molecules small enough to be absorbed into the bloodstream or lymphatic system. These absorbed nutrients are then transported to various parts of the body to be used for energy, growth, and repair. Any undigested material passes into the large intestine.