The digestive glands are important functional units of the digestive system that enable the breakdown of food components. When these organs are diseased, it is not uncommon for serious digestive and metabolic disorders to occur.
What is the digestive gland?
The digestive glands of the human digestive system include the salivary glands, the liver with the gallbladder, the glands of the gastric mucosa, and the pancreas. The digestive glands produce and secrete secretions that are essential for digestion. Without the secretions secreted by the digestive glands, the ingested food could not be broken down into its components. The secretions produced often contain enzymes that are used to digest carbohydrates, fat and protein. In addition, there are digestive glands that secrete a mucilaginous secretion to increase the lubricity of the food pulp. In addition, the secretions produced in the digestive glands can be used to adjust the pH of the food pulp to optimize the breakdown of nutrients. Some enzymes work only under alkaline conditions, while other enzymes prefer an acidic or neutral environment. Without digestive glands, digestion could not occur.
Anatomy and structure
The first step of digestion occurs in the mouth through saliva. Humans have a total of three major salivary glands and many minor ones. The auricular, mandibular, and sublingual salivary glands are anatomically definable organs in the oral cavity. Many small salivary-producing glands are located directly in the mucosa of the mouth. The largest digestive gland in humans, the liver, is located in the right lower abdomen and can weigh up to 2kg. In total, the liver consists of four lobes, which in turn are divided into eight functional segments. Histologically, the liver consists of so-called hepatocytes, which are responsible for the production of bile, among other things. The digestive glands of the stomach are part of the gastric mucosa. At the entrance to the stomach are the cardiac glands. In the upper part of the stomach there are also the fundus glands, which produce gastric juice. The pyloric glands are located at the exit of the stomach. The pancreas is one of the most important digestive glands in humans. Located in the upper abdomen, the organ rarely weighs more than 100g and is divided into three sections, the pancreatic head, the pancreatic body and the pancreatic tail.
Function and tasks
The salivary glands produce saliva, which is secreted into the oral cavity. In an adult, well over one liter of saliva can be secreted per day. Basically, this body fluid serves to make the ingested food slippery. Without saliva, it would be almost impossible to swallow harder food components. Saliva also contains the enzyme amylase, which breaks down carbohydrates. In humans, carbohydrate digestion thus begins in the mouth. In addition to the synthesis of proteins and fatty acids, the liver is primarily responsible for the production of bile acids. Bile acids are formed by liver cells and released into the bile ducts, from where they flow into the gallbladder, where they are stored. Bile contains lipases, which enable the digestion of fats. However, fat digestion does not begin in the small intestine. Fat molecules are already broken down enzymatically in the stomach. The gastric mucosa has three types of digestive glands. The cardiac glands secrete an alkaline mucus so that the food pulp can be transported more easily. In addition, the mucus serves to protect the organs of the digestive tract. Gastric juice is produced by the fundic glands. These glands also add pepsins to the food pulp, which break down some of the proteins contained in the food. The pyloric glands at the exit of the stomach secrete basic mucus, just like the cardiac glands. The pancreas is also located in the immediate vicinity of the stomach and liver. This digestive gland secretes pancreatic juice into the duodenum. The pancreas of an adult can produce up to two liters of secretion daily. The secreted secretion contains various enzymes for protein and carbohydrate digestion. Furthermore, it also contains lipases, which enable fat digestion.
Diseases
The digestive glands of the body perform a variety of important tasks for digestion and thus also for the energy balance of the body. Therefore, diseases of these organs are often particularly consequential.The salivary glands located in the oral cavity can become inflamed and swollen; this is also known as sialadenitis. If the inflammation is not treated, it can lead to secondary diseases. More rarely, the cause of symptoms in the salivary glands is a tumor. Since the liver is a complex organ with a wide variety of functions, there are a number of diseases that can occur here. A typical symptom of liver disease is jaundice. In this case, the mucous membranes or even the skin turn yellowish. Jaundice can be triggered, among other things, by inflammation of the liver (hepatitis). In the case of cirrhosis of the liver, hepatocytes die off to a large extent, massively disrupting the function of the liver. In addition to diseases of the liver tissue itself, the gallbladder can also cause symptoms. If the composition of the bile is not optimal, gallstones can form. Those affected then suffer from very painful colic. In addition, inflammation can occur in the bile duct. The stomach lining can also cause discomfort. Inflammations of the gastric mucosa (gastritis) are particularly widespread. If the pancreas becomes inflamed, pancreatitis is present, usually accompanied by severe pain. In pancreatic insufficiency, part of the glandular tissue is destroyed, which is why a sufficient amount of pancreatic juice can no longer be secreted. Probably the best known disease related to the pancreas is diabetes.
Typical and common diseases
- Sialadenitis
- Salivary stone
- Pancreatitis
- Gastritis
- Diabetes mellitus
- Gallstones
- Biliary colic
- Hepatitis
