Lactealen

Lactealen, also known as lacteals, are the lymphatic capillaries embedded in the lamina propria of the small intestinal villi. They form part of the mucosal lymphatic network and play a central role in the absorption and transport of dietary lipids. The contents of the lacteals are chyle, a lipid-rich lymph that contains chylomicrons formed after fat absorption.

Anatomically, lacteals are blind-ending vessels within the core of each villus. They are slender, thin-walled structures that drain into larger intestinal lymphatic vessels, which ultimately connect to the cisterna chyli and then the thoracic duct, delivering lymphatic fluid to the venous circulation. The endothelial lining features specialized junctions that facilitate uptake of macromolecules and lipids from the intestinal lumen.

Functionally, lacteals are responsible for transporting absorbed lipids from the intestine into the systemic circulation. Following fat digestion and emulsification, enterocytes package fatty acids into chylomicrons, which are then released into the underlying lacteals rather than directly into blood capillaries. From the lacteals, lipid-rich lymph travels through the lymphatic system and eventually enters the bloodstream via the thoracic duct.

Clinical relevance of lacteals lies in their role in lipid absorption and lymph transport. Obstruction or dilation of intestinal lymphatics can lead to lymphangiectasia, causing fat malabsorption and steatorrhea, while impaired lymph flow may contribute to edema or chylous effusions in some disorders. Lacteals are therefore important for nutritional status and overall lymphatic physiology.