Chyloid microparticle (CM): A new CM is generated in the small intestine, which enters the blood through lymphatic vessels to form a mature CM. Its main function is to transport exogenous triglycerides and cholesterol.

Very low density lipoprotein (VLDH): synthesized in the liver. Its main function is to transport endogenous triglycerides.

Low density lipoprotein: converted from very low density lipoprotein. Its main function is to transport endogenous cholesterol.

High density lipoprotein: mainly synthesized in liver, followed by small intestine; In addition, it is converted from CM and VLDL. Its main function is to transport cholesterol in reverse.