Digestion of Lipids (Nursing)

by Jasmine Clark

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    00:00 So now let's take a look at how lipids are digested in the small intestines.

    00:06 This is going to require the process of emulsification.

    00:11 In this process triglycerides and their breakdown products are insoluble in water.

    00:17 So they must be pretreated with bile salts that will break down these larger fat globules into smaller globules that can now come in contact with the proper enzymes.

    00:31 Once they are broken down into more manageable globules digestion is going to take place.

    00:37 During digestion pancreatic lipase has are going to break down our fats into monoglycerides in two fatty acids.

    00:46 So we started as a triglyceride, now we're a monoglyceride and two free fatty acids.

    00:54 Those numbers are important.

    00:56 Next we have my cell formation.

    01:00 This occurs from products from digestion become coated with bile salts and another molecule known as lecithin.

    01:09 From their lipid products will diffuse or leave the micelles and cross the epithelial membrane by way of diffusion.

    01:19 Then we have chylomicron formation.

    01:23 In this process the lipid products are going to be converted back into the triglyceride form and packaged with the lecithin and lipoproteins in the form of a chylomicron.

    01:36 These chylomicrons are then transported or exocytosed from the basolateral side and then instead of entering the blood they enter the lymph by way of the lymphatic lacteals.

    01:51 These are then going to eventually be emptied into the venous blood at the thoracic duct.

    01:59 So once in the blood the chylomicrons are broken into free fatty acids and glycerol by lipoprotein lipase has so that they can be used by the cells.

    02:10 Short-chain fatty acids can diffuse directly into the blood without going through the chylomicron process.

    02:18 So to recap using a diagram.

    02:21 Emulsification involves bile salts that are released from the gallbladder into the duodenum breaking large fat globules into smaller fat droplets that are then going to increase the surface area of the fat available to lipase enzymes.

    02:40 From there, the pancreatic lipase is are going to hydrolyze our triglycerides yielding monoglycerides into free fatty acids.

    02:52 Micelles consisting of the fatty acids and monoglycerides as well as bile salts are then going to ferry their contents to the epithelial cells.

    03:04 After this, fatty acids and monoglycerides are going to diffuse from the micelles into the epithelial cells.

    03:14 Then fatty acids and monoglycerides are recombined and packaged with other fatty substances and proteins to form chylomicrons.

    03:24 These chylomicrons are then extruded from the epithelial cells by exocytosis and enter lacteals and and then are carried away from the intestines in the lymph.

    03:39 So to summarize, some lipid digestion is going to begin in the mouth and the stomach but this is mostly going to occur in babies and less so on adults.

    03:48 After this, most of our lipid digestion is going to actually occur in the small intestines.

    03:54 Where large fat globules are broken down into small droplets by emulsification with bile salts.

    04:04 Emulsification allows the pancreatic lipases to access the lipids where they are broken down into monoglycerides and free fatty acids, once inside the epithelial cells, the monoglycerides and free fatty acids will recombine and are repackaged into chylomicrons.

    04:26 The chylomicrons are then exocytosed to lacteals, which will then be subsequently transported to the lymphatic vessels.

    About the Lecture

    The lecture Digestion of Lipids (Nursing) by Jasmine Clark is from the course Gastrointestinal System – Physiology (Nursing).

    Included Quiz Questions

    1. Micelle formation
    2. Emulsification
    3. Chylomicron transport
    4. Chylomicron formation
    1. Monoglycerides plus 2 free fatty acids
    2. Diglycerides plus 1 free fatty acid
    3. Diglycerides plus 2 free fatty acids
    4. Monoglycerides plus 1 free fatty acid
    1. Chylomicron transport
    2. Diffusion
    3. Emulsification
    4. Chlyomicron formation

    Author of lecture Digestion of Lipids (Nursing)

     Jasmine Clark

    Jasmine Clark

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