Fluid and Enzyme of Digestive Track

Try to give you more information about fluid or enzyme that we can find at our digestive organs. Maybe it is not much, but i hope that this article can help you to understand better about human digestive system.

Oral Cavity Secretions

• Serous (watery) saliva: moistens food and mucous membrane; lysozyme kills bacteria
• Salivary amylase: starch digestion (conversion to maltose and isomaltose)
• Mucus: lubricates food; protects gastrointestinal tract from digestion by enzymes
• Lingual lipase: digests a small amount (<10%) of lipids

Esophagus Secretions

• Mucus:  lubricates the esophagus; protects the esophagus lining from abrasion and allows food to move more smoothly through the esophagus

 Gastric Secretions

• Hydrochloric acid: decreases stomach pH to activate pepsinogen
• Pepsinogen: pepsin, the active form of pepsinogen, digests protein into smaller peptide chains
• Mucus: protects stomach lining from digestion
• Gastric amylase and gelatinase: digest a minor amount of carbohydrates
• Gastric lipase: digests a minor amount of lipid

Liver Secretions

• Bile (consist of Sodium glycocholate, Sodium taurocholate, Cholesterol, Biliverdin, Bilirubin, Mucus, Fat, & Lecithin): Bile salts emulsify fats, making them available to intestinal lipases; help make end products soluble and available for absorption by the intestinal mucosa; aid peristalsis. Many of the other bile contents are waste products transported to the intestine for disposal.

Pancreas Secretions

• Trypsin: digests proteins (breaks polypeptide chains at arginine or lysine residues)
• Chymotrypsin: digests proteins (cleaves carboxyl links of hydrophobic amino acids)
• Carboxypeptidase: digests proteins (removes amino acids from the carboxyl end of peptide chains)
• Pancreatic amylase: digests carbohydrates (hydrolyzes starches and glycogen to form maltose and isomaltose)
• Pancreatic lipase: digests fat (breaks down lipids into monoglycerides and free fatty acids)
• Ribonuclease: digests ribonucleic acid
• Deoxyribonuclease: digests deoxyribonucleic acid (hydrolyzes phosphodiester bonds)
• Cholesterol esterase: hydrolyzes cholesterol esters to form cholesterol and free fatty acids
• Bicarbonate ions: provides appropriate pH for pancreatic enzymes

Small Intestine Secretions

• Mucus : Protects duodenum from stomach acid, gastric enzymes, and intestinal enzymes; provides adhesion for fecal matter; protects intestinal wall from bacterial action and acid produced in the feces
• Aminopeptidase: splits polypeptides into amino acids (from amino end of chain)
• Peptidase: splits amino acids from polypeptides
• Enterokinase: activates trypsin from trypsinogeh
• Amylase: digests carbohydrates
• Sucrase: splits sucrose into glucose and fructose
• Maltase: splits maltose into two glucose molecules
• Isomaltase: splits isomaltose into two glucose molecules
• Lactase : splits lactose into glucose and galactose
• Lipase: splits fats into monoglycerides and fatty acids