- Digestive enzymes - How are food ingredients broken down?
- Digestive enzymes in the mouth
- Digestive enzymes in the stomach
- Digestive enzymes in the intestines
- Digestive enzymes - secretion regulation
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VERIFIED CONTENTAuthor: Natalia Młyńska
Digestive enzymes are substances that are secreted in the digestive system by the digestive glands. They are mostly classified as hydrolytic enzymes that catalyze the decomposition of food compounds, from complex to simpler ones.
Digestive enzymes are mostly hydrolytic enzymes. Thanks to them, it is possible to break down the compounds contained in food into those absorbed by us.
Digestive enzymes - How are food ingredients broken down?
Carbohydrates- are the main source of energy. They are divided into simple and complex. Glucose, which is produced from the breakdown of complex carbohydrates, is the only source of energy for the brain, nerve core and red blood cells.
Proteins- building blocks of the body. They can be of animal or vegetable origin. Protein breakdown leads to the formation of amino acids.
Fats- are a source of energy that can be stored in adipose tissue. During digestion, they are broken down into glycerol and fatty acids. We divide fats into saturated and unsaturated fats due to the presence of double bonds. There are also vegetable, animal, simple and complex fats.
Digestive enzymes in the mouth
When chewing, a large amount of saliva is released into the mouth. Polysaccharides, also known as polysaccharides, for example starch and glycogen, are components of foods that are eaten by humans. Large polysaccharides made of glucose are linked by glycosidic bonds. The hydrolysis of connections takes place thanks to amylases that break down polysaccharides into m altose, disaccharide. Salivary amylase is an enzyme that accelerates the conversion of starch to dextrin and m altose.
We recommend: Watch out for unhe althy simple sugars hidden in drinks!
Starch decomposition under the influence of salivary amylase occurs best at body temperature, the optimal pH is 6.0-7.0. It can break down alpha-glycosyl bonds, but is unable to break down beta-glycosyl bonds, which must be hydrolyzed at a later stage of digestion.
Digestive enzymes in the stomach
Proteins are digested in the stomach thanks to proteolytic enzymes. Each of them breaks peptide bonds. Trypsin, produced in inactive form by the pancreas, is activated by another enzyme -enterokinase. Trypsin activates chymotrypsin and carboxypeptidase. Pepsin, trypsin, and chymotrypsin break some internal bonds of proteins and polypeptides. The carboxypeptidase cleaves amino acids from the end of the polypeptide chain. Dipeptidases are enzymes released by the first part of the small intestine - the duodenum, breaking down small peptides into amino acids.
Good to know: Pancreatic ENZYMES - standards. How to interpret the test results?
Digestive enzymes in the intestines
About 1 liter of pancreatic juice daily enters the duodenum. It is rich in enzymes that digest carbohydrates, proteins and fats. At the same time, the liver secretes about 1.5 liters of bile per day. Bile s alts act as a detergent, i.e. they reduce the surface tension of fats. Emulsification is the breakdown of larger masses of fat into smaller droplets. This process increases the surface area of fat that is exposed to pancreatic lipase, and hence, the rate of digestion is increased.
Fats are digested mainly in the duodenum by pancreatic lipase, which is produced by the pancreas and goes to the small intestine. Apart from glycerol and fatty acids, the digestion products of fats also include monoacylglycerols and diacylglycerols. Some triglycerides remain undigested.
Digestive enzymes - secretion regulation
Most digestive enzymes are only released when food is in the digestive tract. The secretion of saliva by the glands is regulated by the nervous system. Other glands are affected by such an endocrine system.
The enteric nervous system regulates many motor and secretory activities of the digestive system. Neuropeptides such as substance P and enkephalin affect muscle function.
Hormones: gastrin, secretin, cholecystokinin help regulate the secretion of digestive enzymes and affect the work of the entire digestive system. All these hormones are polypeptides secreted by the secretory cells of the gastrointestinal mucosa. Watching, smelling, or tasting food stimulates the centers in the brain, which then send nerve impulses to the glands, stimulating them to secrete.
When food is swallowed, it enters the stomach and stretches its walls, irritating the receptors. They send a signal to the extension core. Further - the centers in the medulla send information to the secretory cells in the organ wall that secrete a hormone, in the stomach it is gastrin. Gastrin gets into the blood, thanks to which it stimulates the stomach to produce gastric juice, additionally influences the increase in emptying and movementintestines.