The most important digestive enzymes are:. Keep reading to learn more about the most essential types of digestive enzymes. Amylase is important for digesting carbohydrates. It breaks down starches into sugars. Amylase is secreted by both the salivary glands and the pancreas.
The measurement of amylase levels in the blood is sometimes used as an aid in diagnosing various pancreas or other digestive tract diseases.
High levels of amylase in the blood may mean you have:. Low levels of amylase may mean you have chronic pancreatitis ongoing inflammation of the pancreas or liver disease.
The small intestine releases maltase, which is responsible for breaking down maltose malt sugar into glucose simple sugar. The body uses glucose for energy.
During digestion, starch is partially transformed into maltose by amylases. The maltase enzyme then changes maltose into glucose. This sugar is then either used immediately by the body or stored in the liver as glycogen for future use. Lactase also called lactase-phlorizin hydrolase is an enzyme that breaks down lactose , a sugar found in dairy products. It turns lactose into the simple sugars glucose and galactose.
Lactase is produced by cells known as enterocytes that line the intestinal tract. Lactose that is not absorbed is fermented by bacteria in the gut. This can cause you to have gas and an upset stomach. Lipase is responsible for the breakdown of fats into fatty acids and glycerol simple sugar alcohol.
It's produced in small amounts by your mouth and stomach, and in larger amounts by your pancreas. Also called peptidases, proteolytic enzymes, or proteinases , these digestive enzymes break down proteins into amino acids.
They also play a role in numerous body processes, including:. Proteases are produced in the stomach and pancreas. The main ones are:. Sucrase is secreted by the small intestine, where it breaks down sucrose the sugar in table sugar into fructose and glucose.
These are simpler sugars that the body can absorb. Sucrase is found along the intestinal villi. These are tiny hair-like structures that line the intestine and absorb nutrients into the bloodstream. There are a variety of health conditions that can interfere with the secretion of enough digestive enzymes to fully digest foods. Some are inherited genetic conditions while others develop over time. Lactose intolerance occurs when you aren't able to digest lactose because of insufficient production of lactase by the small intestine.
When you consume dairy products, you may experience:. There are several forms of lactose intolerance. Congenital Lactase Deficiency. Congenital lactase deficiency also called congenital alactasia is a rare inherited form of lactose intolerance. It happens when newborns are unable to break down lactose in breast milk or formula.
They get severe diarrhea if they aren't given a lactose-free alternative. Congenital lactase deficiency is caused by mutations in the LCT gene that provides instructions for making the lactase enzyme. Skip to topic navigation. Skip to main content. Buscar en la biblioteca.
The Digestive Process: Digestion Begins in the Mouth Digestion is a several-step process that begins the moment you put a piece of food in your mouth or sip a drink. Breaking it down When you begin chewing, glands in your mouth and throat begin to secrete saliva. You have 3 major pairs of salivary glands: Parotid glands, the largest, are on both sides of your face, in front of your ears Submandibular glands are underneath your jawbone Sublingual glands are underneath your tongue Your upper digestive tract and your esophagus also contain smaller clusters of salivary glands.
How does it taste? The role of your teeth Your teeth are also part of the digestive process. To keep your teeth at their healthiest, follow these simple preventive measures: Eat a healthy diet rich in protein, fruits and vegetables, calcium, and whole grains.
Limit eating and drinking between meals. Limit sugary foods and beverages. Brush your teeth and tongue twice a day with fluoride toothpaste, and floss once a day. The apical surface of each villus has many microscopic projections called microvilli. These structures, illustrated in Figure 4, are lined with epithelial cells on the luminal side and allow for the nutrients to be absorbed from the digested food and absorbed into the blood stream on the other side.
The villi and microvilli, with their many folds, increase the surface area of the intestine and increase absorption efficiency of the nutrients.
Absorbed nutrients in the blood are carried into the hepatic portal vein, which leads to the liver. There, the liver regulates the distribution of nutrients to the rest of the body and removes toxic substances, including drugs, alcohol, and some pathogens. Figure 4.
Villi are folds on the small intestine lining that increase the surface area to facilitate the absorption of nutrients. The human small intestine is over 6m long and is divided into three parts: the duodenum, the jejunum, and the ileum. The duodenum is separated from the stomach by the pyloric sphincter which opens to allow chyme to move from the stomach to the duodenum.
In the duodenum, chyme is mixed with pancreatic juices in an alkaline solution rich in bicarbonate that neutralizes the acidity of chyme and acts as a buffer. Pancreatic juices also contain several digestive enzymes. Digestive juices from the pancreas, liver, and gallbladder, as well as from gland cells of the intestinal wall itself, enter the duodenum. Bile is produced in the liver and stored and concentrated in the gallbladder. Bile contains bile salts which emulsify lipids while the pancreas produces enzymes that catabolize starches, disaccharides, proteins, and fats.
These digestive juices break down the food particles in the chyme into glucose, triglycerides, and amino acids. Some chemical digestion of food takes place in the duodenum.
Absorption of fatty acids also takes place in the duodenum. The second part of the small intestine is called the jejunum , shown in Figure 3. Here, hydrolysis of nutrients is continued while most of the carbohydrates and amino acids are absorbed through the intestinal lining.
The bulk of chemical digestion and nutrient absorption occurs in the jejunum. The ileum , also illustrated in Figure 3 is the last part of the small intestine and here the bile salts and vitamins are absorbed into blood stream. The undigested food is sent to the colon from the ileum via peristaltic movements of the muscle.
The ileum ends and the large intestine begins at the ileocecal valve. The appendix of humans secretes no enzymes and has an insignificant role in immunity. Figure 5. The large intestine reabsorbs water from undigested food and stores waste material until it is eliminated.
The large intestine , illustrated in Figure 5, reabsorbs the water from the undigested food material and processes the waste material. The human large intestine is much smaller in length compared to the small intestine but larger in diameter. It has three parts: the cecum, the colon, and the rectum. The cecum joins the ileum to the colon and is the receiving pouch for the waste matter. The colon can be divided into four regions, the ascending colon, the transverse colon, the descending colon and the sigmoid colon.
The main functions of the colon are to extract the water and mineral salts from undigested food, and to store waste material. Carnivorous mammals have a shorter large intestine compared to herbivorous mammals due to their diet. The rectum is the terminal end of the large intestine, as shown in Figure 5.
The primary role of the rectum is to store the feces until defecation. The feces are propelled using peristaltic movements during elimination. The anus is an opening at the far-end of the digestive tract and is the exit point for the waste material. At-home microbiome testing kits can be a first step. We look at these and give our recommendations for your overall gut health questions.
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