What digestive enzymes are contained in the small intestine

The human digestive system is rich in digestive enzymes. The main function of digestive enzymes is to promote the digestion and transformation of food in the human body. Moreover, the types of digestive enzymes contained in each gastrointestinal organ are different, and the small intestine is also an important digestive organ in the human body. The small intestine is also rich in various digestive enzymes. The following article will introduce the digestive enzymes contained in several small intestines.

Enteropeptidase, intestinal lipase, sucrase, maltase, and lactase are secreted by the duodenal glands in the submucosal layer of the duodenum and the intestinal glands in the mucosal layer of the entire small intestine; pancreatic amylase secreted by the pancreas hydrolyzes starch into maltose and a small amount of glucose, and pancreatic lipase hydrolyzes triglycerides into fatty acids, monoglycerides, and glycerol, but requires the presence of bile salts and coesterase; trypsin and chymotrypsin hydrolyze proteins into chondroitin and peptone.

Digestive glands include the salivary glands, pancreas, liver, stomach, and intestinal glands. Both can secrete digestive juices, which contain digestive enzymes.

(1) Salivary glands

There are three pairs of glands: the parotid gland, submandibular gland, and sublingual gland, all of which have ducts that carry the secreted saliva into the mouth. 1 to 1.5 liters of saliva are secreted every day. The amylase contained in saliva can break down starch into maltose. In addition, saliva contains lysozyme, which has bactericidal effect.

(2) Gastric glands

The gastric glands are formed by the invagination of the gastric wall mucosa. They can secrete gastric juice (mainly composed of pepsin) and can initially digest protein.

(3) Intestinal glands

Intestinal glands are tiny glands in the small intestinal mucosa that secrete intestinal fluid, which is alkaline and contains enzymes for digesting starch, protein, and fat. Humans secrete about 1 to 3 liters of intestinal fluid every day.

(4) Pancreas

Located behind the stomach, it is a long, narrow, flat gland close to the stomach and duodenum. The secreted pancreatic juice is injected into the duodenum through the pancreatic duct. Pancreatic juice is alkaline and contains enzymes that digest protein, starch and fat.

(5) Liver

The liver is the largest digestive gland. It is located below the diaphragm and to the upper right of the abdominal cavity. The liver weighs 1.5 kg. The liver can secrete bile, which is alkaline. Although it does not contain digestive enzymes, it can help emulsify fat and turn fat into fat particles. The bile secreted by liver cells is first transported to the gallbladder for temporary storage. When food enters the duodenum, the gallbladder contracts, squeezing the bile out and injecting it into the duodenum through the common bile duct. The end of the common bile duct merges with the pancreatic duct and opens together in the duodenum. There is also a sphincter controlling this area, which is usually tight and will relax and open when eating, allowing bile and pancreatic juice to flow into the small intestine.

In addition, the liver also plays an important role in the metabolism of proteins, carbohydrates, fats, and can decompose and so on.