cholesterol synthesis in liver
The cholesterol (including cholesterol), a fat-like module has to perform vital functions in our body, it is an essential lipid. The cholesterol content of the human body is about 140 g. In humans, the liver and intestinal mucosa, the main sites of cholesterol synthesis. Except in the liver and intestinal cholesterol biosynthesis can proceed with few exceptions, almost all cells of the body. The brain synthesizes cholesterol even required of him, not because of the blood-brain barrier can happen.
organs with high cholesterol needs are the brain and the steroid hormone-producing organs - adrenals, ovaries and testes. About a quarter of total cholesterol is included in the brain where it occurs mainly in the lipid-rich myelin sheaths of axons.
cholesterol is responsible for the construction of stable cell walls, but also in the formation of bile acid in the cells of the liver is required. are cholesterol and other fats, after which they were absorbed in the small intestine, in a protein coat (chylomicrons) packed. Thus, the cholesterol gets "packaged" in chylomicrons via the lymph into the blood. Most of the chylomicron is composed of triglycerides. Excess cholesterol is absorbed in the liver because the liver is the place where the cholesterol mix from the diet and cholesterol from their own synthesis in several chemical steps. The liver is the largest cholesterol stores of the human organism. The memory is only small, if cholesterol is needed for the production of bile acid.
The level of cholesterol depends above all on the body's own production, and only secondarily on the supply of food. There are a variety of genetic hypercholesterolemia. Also as a consequence of other diseases can be elevated cholesterol levels, eg hypothyroidism, renal or metabolic syndrome. In age, the total cholesterol levels significantly.
organs with high cholesterol needs are the brain and the steroid hormone-producing organs - adrenals, ovaries and testes. About a quarter of total cholesterol is included in the brain where it occurs mainly in the lipid-rich myelin sheaths of axons.
cholesterol is responsible for the construction of stable cell walls, but also in the formation of bile acid in the cells of the liver is required. are cholesterol and other fats, after which they were absorbed in the small intestine, in a protein coat (chylomicrons) packed. Thus, the cholesterol gets "packaged" in chylomicrons via the lymph into the blood. Most of the chylomicron is composed of triglycerides. Excess cholesterol is absorbed in the liver because the liver is the place where the cholesterol mix from the diet and cholesterol from their own synthesis in several chemical steps. The liver is the largest cholesterol stores of the human organism. The memory is only small, if cholesterol is needed for the production of bile acid.
The level of cholesterol depends above all on the body's own production, and only secondarily on the supply of food. There are a variety of genetic hypercholesterolemia. Also as a consequence of other diseases can be elevated cholesterol levels, eg hypothyroidism, renal or metabolic syndrome. In age, the total cholesterol levels significantly.
Schema des Cholesterinkreislaufs mit Hilfe der Leber und HDL- und LDL-Cholesterin
In der Regel ist der Cholesterinspiegel bei jungen Frauen etwas niedriger als bei jungen Männern. Mit zunehmendem Alter gleicht sich dieser Unterschied jedoch aus, ältere Frauen haben schließlich im Mittel einen höheren Cholesterinspiegel als ältere Männer. Einen Sonderfall stellt die Schwangerschaft dar, in ihr ist der Gesamtcholesterinspiegel im Normalfall deutlich erhöht.
Da Cholesterin in Wasser unlöslich ist, erfolgt der Transport im Blutplasma zusammen mit anderen lipophilen Substanzen wie Phospholipiden,
Triglyceriden oder Fettsäuren, mit Hilfe von Lipoproteinen. Das über die Nahrung zugeführte Cholesterin sowie Triglyceride werden nach der Resorption aus dem Darm von den Chylomikronen aufgenommen und von dort in die Gewebe transportiert. Lipoproteine verschiedener Dichte (VLDL, IDL und LDL transport) self produced and recorded cholesterol from the liver to the tissues. HDL absorb cholesterol from the tissues and return it to the liver.
chylomicrons (CM), also Lipomikronen are low-density lipoprotein. synthesized in the intestinal mucosa, they go through the lymphatic system into the blood - transport of fat-containing dietary triglycerides - and by lipoprotein lipase to Chylomikronresten (Remnants) degraded in the liver which are the precursors of VLDL and HDL.
cholesterol in the blood mainly in two different forms of transport: the "good" HDL (high density lipoprotein) transports cholesterol from the blood vessels to the liver. So that it protects the blood vessels and can prevent atherosclerosis. The "bad" LDL (low density lipoprotein) transports cholesterol from the periphery to the cells. When a surplus, the LDL cholesterol release, which is deposited on the vessel walls and can lead to atherosclerosis.
of: www.anatomie-physiologie.de
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