Introduction to the Digestive System
Humans, just like any other living organism, require energy for growth and survival. Energy is obtained from food, but to actually extract energy from food, it needs to be broken down in the body. The human body has a specialized system to perform this role. It efficiently breaks down food, enabling our body to absorb required nutrients. Interestingly, the process of digestion starts as soon as you chew your food. In this article, we shall explore how this process works and all the organs involved.
Also called chewing, it is the first step of digestion. The primary role of this process is to facilitate mechanical digestion, where food is broken down into smaller bits by the teeth. This makes the food easier to swallow and also digest. This digestion process also involves special chemicals in the saliva called enzymes. This initiates the process of breaking down starchy food.
Also called swallowing, deglutition helps food to reach the stomach. However, the food does not simply “drop” down into the stomach. Instead, special muscles in the throat force food down a long pipe called the oesophagus. This pipe leads to the stomach, where further digestion follows. Another important aspect we need to know is that there are “flaps” that prevent food from going into the windpipe – when this happens, we choke on our food. This anatomical term for this flap is the epiglottis.
Once the food reaches the stomach from the oesophagus, enzymes start to break down food into its constituents. The stomach also uses strong acid to kill pathogenic bacteria that might be present on our food. Once the food is partially broken down, it is pushed to the next section of the digestive tract – the small intestine.
The small intestine continues the process of digestion by utilizing the digestive enzymes produced by the liver and the pancreases to break food down further. The small intestine is also tasked with absorption of the nutrients extracted from food. These are absorbed by tiny structures called villi, which are then absorbed into the bloodstream.
The next stage of digestion is the large intestine – it is also the last stage of the digestion process. The large intestine absorbs excess water as well as minerals and salts from the undigested food. Any undigested matter that the body can’t use is passed through the large intestine and leaves the body in the form of feces.
Auxiliary Organs and their Functions
Other organs such as the liver and pancreas support the process of digestion by producing digestive enzymes that help break the food down. The liver produces bile, which is crucial for breaking down fat. The pancreas also produces important enzymes which break down proteins, carbohydrates and other substances. Explore more about the human digestive system by registering at BYJU’S Biology. Alternatively, discover other fascinating topics from cardiac cycle and the human heart to nervous system and neurological disorders in humans.