Dünndarmschleimhaut

The Dünndarmschleimhaut, or small intestinal mucosa, is the inner lining of the small intestine. It is a highly specialized tissue crucial for the digestion and absorption of nutrients. This layer is characterized by its folded structure, which significantly increases the surface area available for absorption. These folds are further amplified by villi, finger-like projections that protrude from the surface, and even smaller microvilli on the surface of individual absorptive cells, known as enterocytes.

The primary function of the Dünndarmschleimhaut is to absorb digested food particles, water, and electrolytes from the lumen of the small intestine into the bloodstream or lymphatic system. This process involves a variety of transport mechanisms, both passive and active, depending on the specific nutrient. The enterocytes themselves are rich in enzymes that complete the digestion of carbohydrates and proteins just before absorption.

This mucosal lining also plays a role in the immune system. It contains specialized immune cells and GALT (gut-associated lymphoid tissue) that help to protect the body from pathogens that may enter through ingested food. The Dünndarmschleimhaut is constantly regenerating, with enterocytes having a lifespan of only a few days, ensuring a healthy and functional absorptive surface. Damage to this delicate lining, as seen in conditions like celiac disease or inflammatory bowel disease, can severely impair digestion and nutrient absorption.