Human beings are complex beings and their digestive system is also complex. The human digestive system is made up of an alimentary canal and some accessory glands. Elementary canal is divided into several parts, such as esophagus, stomach, small intestine, large intestine, rectum, and anus. The salivary gland, liver, and pancreas are the accessory glands that are located outside the primary duct.
The human digestive system includes the elemental canal and related digestive glands, they are as follows: –
Elementary canal: This includes the mouth, esophagus, stomach, small intestine, and large intestine.
The main glands are as follows: –
The mouth has teeth and tongue. Salivary glands are also present in the mouth. The tongue has gustatory receptors which perceive the sense of taste.
The tongue helps in turning over the food so that saliva can be properly mixed in it. Teeth help in breaking down the food into smaller particles so that, swallowing of food becomes easier. There are four types of teeth in human beings. The incisor teeth are used for cutting the food. The canine teeth are used for tearing the food and for cracking hard substances. The premolars are used for the coarse grinding of food. The molars are used for fine grinding of food.
Saliva makes the food slippery which makes it easy to swallow the food. Saliva also contains the enzyme salivary amylase or ptyalin. Salivary amylase digests starch and converts it into sucrose.
Food is transported from mouth to stomach by peristaltic action. In which there is a rhythmic contraction of the muscles of the lining of the alimentary canal to advance the food.
The high muscular walls of the stomach help churn food. The stomach walls secrete hydrochloric acid. Hydrochloric acid kills germs. In addition, it makes the stomach acidic. Acidic medium is necessary for gastric enzymes to function. Pepsin, an enzyme secreted in the stomach, performs partial digestion of proteins. The mucus secreted by the walls of the stomach protects the inner lining of the stomach from being damaged by hydrochloric acid. Read More…