Proper digestion is essential for the body to function properly. Proper eating habits, physical activity and attention to hygiene are essential elements that support the digestive system. We all know that our bodies digest - but how do they do it? We take a closer look at the topic.
Table of contents:
- How is our digestive system structured?
- Where does the digestive process start?
- Time for the stomach
- Small intestine and large intestine
- The last stage of a long journey
During digestion, the body breaks down compounds into smaller parts, allowing them to enter cells and, among other things, provide energy.
How is our digestive system structured?
The human digestive system, also known as the gastrointestinal tract, consists of a number of organs. These work together to digest food, absorb nutrients and remove debris. The entire digestive tract of an adult human is approximately 9 metres long and consists of the following components:
- mouth - and this is where the whole process begins,
- oesophagus,
- stomach,
- small intestine,
- large intestine,
- rectum.
The list does not end there, as the teeth, tongue, salivary glands, liver, pancreas, gallbladder are also involved in the whole process. These organs effectively support the whole process: they facilitate the grinding of food, secrete enzymes and other substances that enable the absorption of nutrients.
The digestive process: how does it work?, photo: panthermedia
Where does the digestive process start?
It would seem that digestion begins once the food has entered the stomach. The above list of organs involved in this process shows that this is not the case; moreover, the process begins even before the food is placed in the mouth. The very smell or thought of it stimulates the salivary glands to produce saliva.
Once the food enters the mouth, saliva moistens the food, the teeth and tongue break it down mechanically, in turn salivary amylase breaks down complex sugars. When chewed, the food becomes a small, round mass called a food bite, making it easier to swallow.
In the next step, it is the oesophagus that begins its work. After swallowing, the bite of food enters the oesophagus, where it moves into the stomach thanks to the force of gravity and muscle contractions. We are very familiar with this process, and its specialised name is peristalsis, the rhythmic contraction of the smooth muscles of the digestive tract.
Stomach time
The food bite then passes through the lower oesophageal sphincter into the stomach. Here, many processes take place as the food is temporarily stored and the stomach cells secrete gastric juice. In addition, the muscles of the stomach stir and break down the food content.
The digestive system: what does it consist of?, photo: panthermedia
The result of this work is the formation of gastric contents, known as food pulp.
It is worth mentioning that gastric juice contains hydrochloric acid, which is very important in the whole process, but not only. It also has key functions for our health. This is because it destroys microorganisms, in addition, it breaks down proteins and plant fibres and activates pepsin. In addition, this acid can damage the walls of the stomach, so some cells produce protective mucus.
Small intestine and large intestine
The stomach does not absorb many nutrients - the food pulp passes through the pyloric sphincter into the small intestine, which is about 6 metres long and absorbs the vast majority, about 90%, of nutrients. It consists of three parts: the duodenum, the jejunum and the ileum.
The duodenum is responsible for receiving food pulp from the stomach and digestive enzymes from the liver and pancreas. The jejunum, in turn, is where most of the chemical digestion and absorption of nutrients takes place. The last part, the ileum, contains the ileocecal valve, through which food passes into the large intestine - the place where undigested food debris ends up.
The digestive process: large and small intestine, photo: panthermedia
The large intestine is approximately 2 metres long and is where faeces are formed. This is also where the body absorbs water and electrolytes. Intestinal bacteria break down food debris and peristalsis moves the faeces to the rectum.
The final stage of the long journey
As the faeces move into the rectum, receptors detect a stretch and stimulate the defecation reflex.
There are two types of contraction in our body associated with the defecation process. The automatic smooth muscle contraction of the internal anal sphincter, which is not dependent on us, and the - already conscious - control of the external sphincter. We are therefore able to control when a bowel movement occurs. However, it is worth listening to your body and not delaying the process too long, because if the faeces remain in the intestine for too long, the body absorbs more water, which leads to constipation.
As you can see, the digestive system is a complex system, with each organ playing an important role, but working together allows for efficient digestion and absorption of nutrients.