how do lipids move through the body so they can be digested and absorbed? How are lipds stored in the body?
http://en.wikipedia.org/wiki/Fat
http://www.chem4kids.com/files/bio_lipids.html
Lipids, also known as fats, move through the body and are processed through a series of steps in order to be effectively digested and absorbed. Here's an explanation of how lipids travel and are stored in the body:
1. Ingestion: Lipids enter the body through the diet, mainly in the form of triglycerides found in foods such as oils, butter, and fatty meats.
2. Emulsification: Once in the stomach, lipids undergo partial digestion as they come into contact with gastric acid and enzymes, resulting in the formation of small droplets called emulsified lipids.
3. Bile secretion: The emulsified lipids then enter the small intestine, where bile, produced by the liver and stored in the gallbladder, is released. Bile plays a crucial role in breaking down the large lipid droplets into smaller droplets, aiding in digestion.
4. Enzymatic digestion: In the small intestine, pancreatic lipase, an enzyme secreted by the pancreas, acts on the emulsified lipids. Pancreatic lipase breaks down triglycerides into free fatty acids and monoglycerides, which are easier to absorb.
5. Micelle formation: Free fatty acids and monoglycerides combine with bile salts to form micelles. Micelles are tiny spherical structures that help solubilize the lipid compounds, enabling them to be transported across the intestinal lining.
6. Absorption: Micelles move towards the intestinal villi, which are small finger-like projections on the intestinal lining. Within the villi, free fatty acids and monoglycerides are taken up by the absorptive cells of the small intestine through a process called passive diffusion.
7. Repackaging: Once inside the absorptive cells, the free fatty acids and monoglycerides are reassembled into triglycerides. They combine with proteins and form chylomicrons, which are large molecules that enable the transport of lipids through the lymphatic system and eventually into the bloodstream.
8. Blood circulation: Chylomicrons travel through the lymphatic vessels and enter the bloodstream through a large vein near the heart. From there, lipids can be distributed to various tissues and organs throughout the body.
Storage of lipids:
In the body, lipids are primarily stored in specialized fat cells called adipocytes. Adipose tissue, commonly known as fat tissue, serves as a major energy reservoir. Excess dietary lipids are converted into triglycerides and stored within adipocytes in the form of lipid droplets. When energy is needed, these stored triglycerides can be broken down and released into the bloodstream, providing a source of energy for the body.