A lacteal is a lymphatic vessel in a villus of the small intestine which conveys chyle from the intestine through the mesenteric glands to the thoracic duct.

 

The most familiar function of the lymphatics is to carry lymph from the tissues back to the blood stream, but the great network of lymphatic vessels which serves the intestines also transports nutrient substances from the food.

 

During digestion the small molecules into which food is broken down find their way into the millions of tiny villi which line the interior of the intestinal wall. Some of these food molecules are carried away in the blood stream, but others, particularly fats, enter the lymphatic capillaries, the lacteals, one of which lies in the center of each villus.

 

The milky mixture of lymph and nutrients, known as chyle, is carried by the lacteals to the lymph vessels in the intestinal wall. It is then collected into the larger vessels which course through the mesentery and is carried into the cisterna chyli.