If you have ever poured oil into a glass of water, you have seen that these two substances do not mix. Knowing this, how do lipids move through the body so they can be digested or absorbed? How are lipids stored in the body?

Since this is not my area of expertise, I searched Google under the key words "lipid digestion" to get these possible sources:

http://arbl.cvmbs.colostate.edu/hbooks/pathphys/digestion/smallgut/absorb_lipids.html
http://www.annecollins.com/digestive-system/digestion-of-fats.htm
(Broken Link Removed)
http://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb2/part1/lipoprot.htm

In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.

I hope this helps. Thanks for asking.

If you have ever poured oil into a glass of water, you have seen that these two substances do not mix. Knowing this, how do lipids move through the body so they can be digested and absorbed? How are lipids stored in the body? Explain your answer.

Lipids are a class of molecules that include fats and oils. Their unique property of not mixing with water is due to their hydrophobic nature, meaning they repel water. This characteristic creates challenges for their movement and storage in the body.

To understand how lipids move through the body, let's start with digestion. The process of lipid digestion begins in the small intestine. When you consume lipids in your diet, they are broken down into smaller molecules called fatty acids and glycerol by enzymes known as lipases. This breakdown process enhances their solubility in water. However, even after digestion, lipids can't be directly transported in the bloodstream because they are hydrophobic and would simply coalesce into large droplets.

To overcome this problem, the body has devised a clever solution. During digestion, bile salts are released by the liver and stored in the gallbladder. These bile salts act as emulsifiers, which means they break down the large lipid droplets into smaller droplets called micelles. Micelles are formed by surrounding the lipid molecules with a layer of bile salts, making them soluble in water. This allows the micelles to effectively transport lipids through the watery environment of the small intestine.

Once the lipids are in the form of micelles, they can come into contact with the absorptive cells lining the small intestine, known as enterocytes. The lipids diffuse into these cells and are reassembled into triglycerides. Triglycerides are a type of lipid that can be easily stored in the body. Inside the enterocytes, triglycerides combine with proteins to form particles called chylomicrons. Chylomicrons are large droplets that are too big to enter the bloodstream directly.

To get the lipids into the bloodstream, the chylomicrons are transported via the lymphatic system, specifically the lacteals, which are lymphatic vessels in the small intestine. From the lacteals, the chylomicrons enter the larger lymphatic vessels and eventually reach the bloodstream near the thoracic duct. Once in the bloodstream, lipoprotein lipase, an enzyme found on the inner surface of blood vessels, breaks down the triglycerides in the chylomicrons into free fatty acids and glycerol. These breakdown products can then be taken up by various tissues in the body for immediate energy needs or stored for later use.

Regarding lipid storage in the body, adipose tissue plays a crucial role. Adipose tissue is a specialized connective tissue primarily composed of fat cells called adipocytes. When there is an excess of lipids in the bloodstream, adipocytes take up fatty acids and glycerol from the bloodstream and store them as triglycerides within lipid droplets inside the cells. These stored triglycerides serve as an energy reserve that can be mobilized when energy is needed, such as during periods of fasting or physical activity.

In summary, lipids move through the body via the formation of micelles during digestion, which ensures their solubility in the watery environment of the small intestine. They are then absorbed by enterocytes, reassembled into triglycerides, and packaged into chylomicrons for transport through the lymphatic system into the bloodstream. Lipids can be stored as triglycerides in adipose tissue for future energy needs.