How the body uses fat?
Sources of energy: Glucose, glycogen and fat are sources that use our body to make energy, we use metabolic pathways that convert nutrients. The body can process fat by digestion, transport, conversion and energy extraction.
Glycogen: It’s a carbohydrate made by a lot of glucose molecules. Is made and store in the liver and muscles. It can be broke into glucose so it’s a energy reserve. We have a low glycogen reserve and can be expended in hours.
Glucose: It’s the brain primary source. It is obtained from sugar,carbohydrates like starch, by breaking down glycogen and converting glycerol from fat. It’s easily transported through the bloodstream but not easily stored.
Fat: Is a long term source for the body. The fat from the food is dissolved in the fatty acids and then, they travel through the bloodstream. Useless fatty acids are stored and feed the fat cells which are unlimited in space, for keeping it. The molecule is made by 3 fatty acids and a molecule of glycerol.
Metabolic pathways of fat and sugar : A person can become obese for eating a lot of sugars and carbohydrates that convert into fat. depending on how many you need and how many you have, enzymes reactions turn sugar into fat and fat into sugar.
Fat to sugar: The glucose comes from glycogen, the triglycerides are divided in glycerol turned into glucose and fatty acids are for obtaining energy.
Sugar to fat: When the sugar is plentiful, we can complete the metabolic demands. If we have a lot of glucose the liver converted into glycogen. If there is more is convert into triglycerides.
Digesting fat
When a person eats, the food digestion start with mechanical digestion in the mouth and stomach. The solid food breaks into fat droplets that can be use or stored.
Emulsification: The bile acids are produced in the liver and store in the gallbladder. It emulsify the fat droplets and broken in smaller droplets. The droplets aids help in the subsequent digestive process.
Chemical digestion:The Pancreas has a connection with the small intestine. Their juices are founded in the duodenum which comes with the enzyme pancreatic lipase. This enzyme digests the triglycerides turning them into 2 fatty acids and a monoglyceride.
Absorption and packaging: Fatty acids and monoglycerides are absorbed by the small intestine and assembled with triglycerides. Fatty acids and triglycerides are not easily transported through the bloodstream so triglycerides are transported in packages into particles called chylomicrons. And that is how it can travel through the bloodstream.
Fate of ingested fat: The chylomicrons get to the fat tissue and muscles activating lipoprotein lipase and then it breaks down into triglycerides for absorption burned for energy. For the lipid metabolism, the liver is essential.
Transporting fat
Lipoproteins: As an outer shell, it have a monolayer of phospholipids and create a hydrophobic in the interior. And the ones with bilayers created hydrophilic.
Lipoprotein functions:
The proteins have an specific function. Some of them are: Chylomicron that carries fat and cholesterol founded in the intestine to all the body, Chylomicron remnant that carries to the liver remaining fat and cholesterol, VLDL provides the body with fat from the liver, LDL with cholesterol provides the body, HDL the excess of cholesterol founded in the tissues is carried to the liver, etc.
Lipoproteins and health: The liver sends VLDL to the fat and it converts into LDL, supplying the body with cholesterol. The excess is converted into HDL and returned to the liver. Sometimes we said that the cholesterol is bad or good but the ones that made that are the LDL (bad) and the HDL (good).
Lipoprotein structure: The surface is called apolipoproteins that contains proteins and cholesterol molecules. Then is the phospholipid that have cholesterol molecules. And inside are triglycerides with cholesterol ester.
Lipoprotein diversity: There are many types of lipoproteins. They are differentiated by different tissues, modifying other lipoprotein. Their name makes reference to their density. Some of them are:Chylomicron and its source is the small intestine, Chylomicron remnant and its source is the chylomicron, VLDL (very low-density lipoprotein) which comes from the liver, LDL (low density protein and its source VLDL, HDL (high-density lipoprotein) that has various sources, etc.
Albumin: The plasma protein albumin transports the fatty acids that come from the adipose tissue. The liver synthesizes the protein that is the one that is more present in the blood. Is can travel with seven fatty acids and they can have different functions such as being used by the liver, muscles or other tissues.
Intracellular transport: The fatty acids are insoluble in blood and in the cell’s cytoplasm. So without it, fatty acid encapsulated the proteins.
Endogenous fat:
The fat is stored in the adipose tissue and the liver regulates the amount of fat in the circulation. A connection or nexus of the nutrient pathways is the liver because it release cholesterol and fat, convert sugar into fat and fat into sugar, also synthesized different molecules such as glycogen.
Storing fat: Sugar is converted into fat and glycogen in the liver. In the VLDLs the triglycerides are liberated that through the time they became in LDLs.
Burning fat: During the time between the meals, the energy provided to the body is the union between the albumin and the fatty acids released from the adipose tissue. That energy is used by the liver for the production of glucose. Liver and muscles have stored glycogen, they convert it into glucose and then to energy.
Ketone bodies
They are agrupated molecules that include acetoacetate. When there is no food in the stomach, the acetyl-coenzyme A is produced in order to decompose the fatty acids. Some of those molecules turn in the liver into ketone bodies.