The process by which large food molecules are broken down into smaller ones by the action of digestion and accessory glands enzymes.
Parts of the digestion system
The digestive system has been divided into the following parts
The oral cavity is the first part of the digestive system. When we eat food it is broken down into very smaller pieces by teeth. There are 4 types of teeth called incisors, canines, premolars, and molars which help in semi breakdown of food. In mammals, salivary glands named parotid, sublingual and submandibular are present which secretes many enzymes. One of the most important enzymes is salivary amylase which starts the partial digestion of food. Here starch from carbohydrates is broken down. The tongue also helps and convert food into a ball-type structure called bolus which is pushed back into the second part of the esophagus.
As we know trachea and food pipe are present sides by side so in order to prevent food from entering the trachea a lid-type structure covers the top of the trachea and food easily passes into the stomach. Peristalsis and gravity help in moving food in the esophagus.
The stomach is the third part of the gut. It is j shaped present at the left side of the body. Bolus enters into the stomach by an opening or gate in the stomach called a cardiac sphincter. After the food enters the stomach different kinds of chemicals and enzymes enter it, for example, the enzyme pepsin is secreted in inactive form pepsinogen.
HCL is also secreted from the walls of the stomach and converts pepsinogen into pepsin which converts peptides and polypeptides. HCL is secreted in concentrated form so in order to prevent any injury a thick layer of saliva or mucous covers it. The digestive system also secretes digestive enzymes. Walls of the stomach also contract and relax and produce heat helping digestion. In infants renin enzyme is produced for milk digestion at last food is converted into a soapy liquid structure called chyme and leaves the stomach through the pyloric sphincter.
The small intestine has three main parts duodenum, jejunum, and ileum. Duodenum is the first part of the small intestine and is about 20 to 25 cm in length. It is the smallest part next is jejunum about 2.5 m and ileum is around 3.5 m. Bile is a juicy chemical mixture produced in the liver and stored in the gall bladder is secreted in the small intestine. In the small intestine, carbohydrates are converted into simpler form glucose.
Trypsin is also produced in the small intestine in inactive form trypsinogen and does digestion of protein. An enzyme called enter kinase is also produced. For digestion of lipids, lipase is produced and this process is called emulsification, and lipids are converted into simpler substances glycerol and fatty acid. The third part of the small intestine is the ileum and consists of finger-like projections called villi. Villi consist of many blood capillaries and lacteal.
The large intestine is the last part of the gut and consists of three parts cecum rectum and the colon. Here most of the water is absorbed and feces or stool is produced. Feces is temporarily stored in the anus unless a person feels the need of using the bathroom.
The liver is the largest part of the body and is present at the right side of the body its function is to purify blood for the detoxification of blood bile is produced from the liver and stored in the gall bladder.
The pancreas is present behind the stomach and produces pancreatic juice.
The GI tract is also called the alimentary canal or gut it starts from the mouth and ends into the anus/rectum. It is m in length. Walls of the gut contract and relax rhythmically a process called peristalsis. It is about 9 meters in length.
Maladies of the digestive system
It is the condition when a very large amount of water is absorbed in the large intestine and the feces become very hard and it becomes very difficult for the faces to pass in the large intestine when the feces pass the person can feel pain and an analytical bit of bleeding can also occur constitution is known as the mother of the diseases and it causes include drinking very less amount of water. It can be prevented by taking a large amount of water eating leafy green vegetables.
The file is a condition in which the walls of the intestine become swollen and inflamed and the patient feels very itching and pain during excretion and it can follow by heavy bleeding usually the pile Go Away on its own but if the condition is very worse then the patient has to go through a surgery to remove the damaged intestine part for its prevention drink lots of fluid and water and if the bile is hurting take Paracetamol as a painkiller it is usually caused by chronic constipation
Diarrhea condition when the intestine is not absorbing water perfectly large amount of watery feces a stool is produced it is usually caused by bacteria it can be treated by taking over ORS.
In Ulcer walls of the stomach become inflamed and are caused by eating spicy food and caffeine and missing meals it eventually will turn into ulcer cancer if not properly treated.