Digestive Juices and Carbohydrate Metabolism Functions

Role of Biliary Juice

The biliary juice neutralizes the acidity of the chyme, favoring the action of pancreatic and intestinal enzymes. This action promotes the absorption of fats and fat-soluble vitamins. It emulsifies fats while promoting their digestion by gastric lipase. Furthermore, it stimulates the formation of bile in the liver and removes waste products eliminated by the cells.

Components of Bile Juice

• Biliary Pigments: These excretion products are transported to the liver as a result of red blood cell destruction.
• Bile Salts: These emulsify fats to help digestion and absorption. They are composed of reabsorbable cholesterol, which fully returns to the liver through the portal vein.

Pancreatic Juice and Enzymes

• Sodium Bicarbonate: Neutralizes hydrochloric acid.
• Trypsin and Chymotrypsin: Digest proteins into peptides and amino acids.
• Amylase: Digests starches into maltose.
• Pancreatic Lipase: Digests fats into fatty acids and glycerin.

Complex Carbohydrates

• Plant Starch: A polysaccharide that is most abundant in cereals, tubers, and pulses (such as potato).
• Animal Glycogen: A polysaccharide that is most abundant in animal cells. It consists of glucose molecules and is found abundantly in the liver and skeletal muscles.
• Cellulose and Hemicellulose: Polysaccharides found in the cellular walls of all vegetables; they are absorbed by herbivores.
• Pectins: Polysaccharides found in plant structures that are not absorbed by humans.

Intestinal Juice Functions

• Peptidases: Digest peptides into amino acids.
• Disaccharidases: Deployment of double sugars into simple sugars or monosaccharides.
• Intestinal Lipase: Acts on fat broken down into glycerol and fatty acids.
• Intestinal Amylase: Acts on the remains of starches broken down into double sugars.

Components of Gastric Juice

• Mucus: Protects the gastric mucosa.
• Hydrochloric Acid: Softens protein and eliminates microorganisms.
• Intrinsic Factor: Helps the absorption of Vitamin B12.
• Pepsinogen and Pepsin: Digests proteins into peptides.
• Gastric Lipase: Digests fats or lipids emulsified into fatty acids and glycerin.

Simple Carbohydrates and Sugars

• Glucose: A simple monosaccharide and the most abundant in nature. It is used by every cell in the body; the nervous system, kidneys, and red blood cells can only use glucose.
• Fructose: A monosaccharide found in fruits, honey, and some vegetables.
• Sucrose: A disaccharide present in table sugar, comprising two glucose molecules.
• Lactose: A disaccharide which is the sugar from the milk of mammals.