Digestion is a fundamental part of human survival. Through this process, people can replace the nutrients in food within our bodies with other beneficial substances to keep us alive. But this does not happen only in people, there are many animals and plants that perform this function in order to survive.
There are two types of organisms that use different functions to feed themselves and obtain energy. There are the heterotrophic organisms, which will depend on supplying themselves with raw material to be able to maintain, grow and function. Autotrophic organisms (they are plants and photosynthetic organisms) will capture their energy through light, which will transform it into chemical energy.
What is digestion in people?
As main theory, digestion is the transformation of food by hydrolysis, which will turn into small substances called nutrients. These substances will cross the plasma membrane by a chemical reaction where it will be helped by enzymes. This process happens mainly in the stomach, although there are many other organs that are part of the digestive system.
The basic organs for this digestion to occur are: the mouth, tongue, pharynx, esophagus, stomach, liver, pancreas, small and large intestine, rectum, and anus.
In this transformation of food into substances, digestion is responsible for separating nutrients from toxins and residual elements. Then the organism will be in charge of distributing these nutrients throughout the rest of the organism and thus it will be transformed into energy, something vital for subsistence. The toxins and the residues that are not favorable will be in charge of being expelled.
Why is digestion important?
Because it is vital for our development and survival. With the intake of food we are ingesting nutrients such as proteins, vitamins, fats, carbohydrates, minerals and water. They are essential components to survive, grow, repair our body and have energy.
Step by step on digestion:
Ingestion
Digestion begins in the mouth: we introduce food into the mouth and perform a mechanical action that consists of chewing and breaking down food with the help of molars and salivary glands. What is called the bolus is produced that with the action of swallowing it will pass through the pharynx and from there to the esophagus.
In the esophagus the food bolus will be pushed into the stomach Thanks to some movements (the perisaltics), this is where the main step of digestion will take place.
The digestion
In the stomach is where this activity occurs. Through muscular movements gastric juices will be secreted that will make the bolus unravels and that is when it transforms it into chyme.
The digestive glands participate in this process of secreting enzymes: the liver and pancreas, which will be responsible for helping to break down food.
Absorption
At this stage, the chyme, bile and digestive juices reach the small intestine and this is when it is produced. transformation into nutrients. At this moment is when we can talk about chemical digestion, and it is when all these elements are doing their process so that the chyme breaks all the intermolecular bonds.
Egestion
It is the final part of digestion and is where the large intestine participates. Is about a process where toxins and waste that the body does not need are going to be eliminated. It is everything that has not been absorbed by the small intestine and has been transformed into a nutrient. These wastes are transformed into feces, they travel through the rectum and are expelled through the anus. At this point is when we talk about evacuation or defecation.