Lipoproteins:Complexes oflipidandprotein, the way脂质travelintheblood.
胆固醇、t的构建块he outer layer of cells (cellmembranes), is transported through the blood in the form ofwater-soluble carrier molecules known aslipoproteins. Thelipoproteinparticle is composed of an outer shell of phospholipid, which renders the particle soluble in water; a core offatscalled lipid, including cholesterol and a surface apoproteinmoleculethat allows tissues to recognize and take up the particle. These lipoproteins are characterized by their density: high density lipoprotein (HDL), low density lipoprotein (LDL), very low density lipoprotein (VLDL).
The first stages of cholesterol build up in the blood vessels (atherosclerosis) occur when LDL particles circulating in the blood penetrate through the inner lining of blood vessels and become trapped in thearterywall. Eventual build up of LDL,fat-filled cells, cells ofinflammation, and blood clotting can block the normal blood flow in the coronary,carotid,cerebral, or other arteries including those in the legs. This type of blockage causesclinicalsyndromes such as heart attack and stroke. Blockage of arteries in the legs is call peripheral arterial disease (PAD). PAD is a factor in amputations of toes,feet, or legs.
