[Biology Class Notes] on Digestion of Dietary Fatty Acids Pdf

To perform our daily work, we need enerDiarrhoeahat energy is provided to us by the food. The food we eat is digested in our digestive system and its breakdown provides us energy. So, digestion is the process by which the food we intake is broken down from its complex form to a simpler form. This is done by the action of enzymes that act on the food inside our digestive system. Almost all types of food and nutrients are digested and absorbed by our digestive system such as carbohydrates, fatty acids, proteins, vitamins, amino acids, etc. The mouth, alimentary canal, stomach, liver, pancreas, small intestines, large intestines, and the anus together make up the human digestive system. We will learn about dietary fat absorption steps in the below paragraphs. 

Digestion in the Small Intestine

The digestion of dietary fatty acids takes place in the small intestines. There are various enzymes that are mixed in the small intestines. The bile juices, the enzymes from the pancreas, and the enzymes of the small intestines together facilitate the digestion of dietary fatty acids. The enzymes from the pancreas that are present in the small intestines are Chymotrypsinogen, trypsinogen, amylases, nucleases, lipases, and carboxypeptidase. The bile salts and the bile pigments that are the bilirubin and the biliverdin play a chief role in the absorption of fatty acids. This process of dietary fat absorption steps is known as the emulsification of fats. This means that the fat globules are broken down into smaller micelles. These micelles are a combination of bile salts and fatty acids. The lipase enzyme from the pancreas and the small intestine also plays a major role in the digestion of fatty acids. These fats are broken down into diglycerides and then further monoglycerides. By the muscular layer of the small intestine, various types of movements are generated. These movements help in the proper mixing of all the juices that are present in the small intestines. The goblet cells are present in the mucosal epithelium of the small intestines and this mucus helps in lubricating and protecting the walls of the small intestines. Lipases, dipeptidases, and nucleases are present in the intestinal juice. Human beings are also able to digest the lactose that is present in the milk. But when our age increases, then there is a problem in the digestion of the milk. The reason behind this is that there is a decrease in the amount of lactase enzyme. When the lactose is not digested then it is present in the stomach only and starts producing different gases and acids. Galactosemia is a disorder when humans are not able to digest lactose. 

Dietary Fat Absorption Steps

Smaller and soluble molecules such as glucose and amino acids are absorbed by the process of simple diffusion. For the absorption of fatty acids, simple diffusion cannot take place because the fatty acid molecules are insoluble in nature and thus they are not easily absorbed by the blood. The steps involved are:

• The fats are digested in the form of fatty acids and glycerol. 

• These fatty acids and glycerol and water-insoluble molecules. 

• Their absorption in the small intestines takes place in the form of micelles. These micelles are soluble in nature. 

• By the formation of micelles, the fatty acids and glycerol are absorbed into the intestinal cell. 

• These fatty acids and glycerol from triglycerides. 

• These triglycerides are then surrounded by a protein layer. When this happens, it is known as a chylomicron. 

• These chylomicrons are then absorbed into the lymphatic system or lymph vessels. 

• From the lymph vessels, these chylomicrons or fat molecules are deposited onto the adipose tissue. 

• Bile salts are responsible for the formation of micelles.