Food gives us the energy to work and play. To be of use to the body, the food we eat has to be digested properly. We eat many different kinds of food in the course of a day. The digestive system breaks down this food into smaller parts that can be easily absorbed by the body. This process is called digestion.
Many organs form the digestive system and help the digestion to take place successfully.
Teeth bite off and chew food into a soft pulp that is easy to swallow. Chewing mixes the food with saliva and makes it moist and slippery.
The oesophagus, or gullet, is a muscular tube. It pushes food into the stomach. It moves food by contraction of its muscles.
The stomach walls are made of thick muscles. These contract to mash the food into a semi-solid state. The stomach lining produces strong digestive juices. The food then enters the small intestine.
The small intestine is a narrow, but very long, about 20 feet. Powerful digestive juices from the pancreas and gall bladder dissolve the nutrients in the food so they can be absorbed by the body. Finally the nutrients are small enough to pass through the lining of the small intestine, and into the blood.
Blood from the intestines flows to the liver, carrying nutrients, vitamins and minerals. The liver stores some nutrients and changes them from one form to another. It then releases them into the blood acccording to the activities and needs of the body. It also detoxifies many harmful substances in the blood.
Any useful substances left are absorbed through the walls of the large intestine, back into the blood. The remains are formed into brown, semi-solid faeces, ready to be removed from the body.
Rectum and anus:
The large intestine then passes all the leftover food that the body does not need to the rectum and it leaves the body as waste through the anus,
Functions of the digestive system are:
To break down food into smaller parts.
To dissolve nufrients with the help of digestive juices.
To let the nutrients get absorbed by the body through the blood.
To let the body use the nutrition and energy to work and play.