How are lipids metabolized?

Lipid metabolism initiates in the intestine, where triglycerides from ingested food are catalyzed by pancreatic lipases into monoglyceride molecules. These enzymes act after bile salts emulsify fats. Following this breakdown, small molecules (e.g. glycerol), medium-chain, and short-chain fatty acids are absorbed by the small intestine and enter the bloodstream. Once monoglycerides and long-chain fatty acids are absorbed, the small intestinal cells reassemble them into triglycerides. 

When food arrives in the small intestine as chyme, the release of the digestive hormone cholecystokinin (CCK) is triggered by intestinal cells. CCK prompts the pancreas to release pancreatic lipase, aiding in fat digestion. It also induces the gallbladder to contract, releasing stored bile salts into the intestine. The triglycerides, as well as phospholipids, proteins and cholesterol, combine to form chylomicrons. Chylomicrons serve as carriers allowing fats and cholesterol to travel along the lymphatic system and enter the bloodstream. Chylomicrons exit via exocytosis and enter the lymphatic system through lacteals in the interstitial villi. From there, they travel to the circulatory system. The liver and pancreas are crucial organs for lipid metabolism, playing key roles in the digestion, synthesis, breakdown, absorption, and transport of lipids. Chylomicrons may also be stored in adipocytes.