In this article we are going to talk about the process of digestion and absorption of nutrients.
The whole process starts from the mouth. And it continues to the intestines. Have you ever thought about how long the food travels in your body?
A properly functioning digestive system can absorb about 97% of the food intake. In diseases of the digestive tract, this percentage may drastically decrease. The main goal of the body is to extract all beneficial substances from the food and to protect it from harmful microorganisms and toxins.
After chewing and swallowing the food, it goes to a few-hour adventure in the digestive system. Its total trajectory is about six-seven meters. The process starts from the mouth and ends with the anus.
The food first enters the mouth where it is broken down into smaller particles by chewing and is softened by the saliva. A small part of the absorption of nutrients begins in the mouth. The mechanical processing of the food is done by the teeth, tongue and muscles of the cheeks. Saliva is responsible for the chemical processing. It contains enzymes such as amylase, lipase and maltase that help the chemical process. A person processes one liter and a half saliva per 24 hours.
Once the food is crushed in the mouth, it passes through the pharynx and when we swallow, it goes to the food pipe that transports it to the stomach. The food pipe ends with a one-way valve, known as an esophageal sphincter, which prevents food and fluids from returning to the esophagus or mouth. When the valve is damaged it is possible to open at the wrong time. This problem is known as gastroesophageal reflux, which cause burning sensation, pain and nausea.
The actual digestion of food happens in the stomach. It is located between the esophagus and the small intestine. Its location is just below the heart. With the help of stomach acid, the pieces of food that are crushed in the mouth turn into mash. The stomach acid destroys harmful toxins and microorganisms in the food. The acidity is extremely high with a pH of up to 1.
The stomach juice contains enzymes that are responsible for the digestion of food and the absorption of beneficial substances. Thanks to the stomach muscles the food shifts and gets in contact with the acids. The stomach is made up of four layers that are responsible for transporting the food to the intestine.
When the stomach completes its functions and the food is broken down to a mash, active muscle contractions move the food to the duodenum. The food slowly enters the duodenum. The duodenum is the beginning of the small intestine. In it the mash is subjected to enzyme containing juice obtained from the bile and pancreas. The duodenum assimilates the simple sugars and fat soluble vitamins.
After the duodenum, food goes through the jejunum and ileum, which are also part of the small intestine. The food continues to be processed and nutrients are being absorbed.
It also has several parts. The large intestine starts with the so-called blind intestine (cecum), continues with the appendix, transverse colon and sigmoid colon and ends with the rectum.
The content that goes to the large intestine consists of predominantly indigestible ingredients from food, water, and some digestive juices. The main functions of the large intestine are two - to absorb water and to eject feces. It contains millions of harmful and beneficial bacteria that form the so-called intestinal flora, which is necessary environment.
The food route from mouth to anus lasts from 18 to 72 hours. Duration depends on your eating and driving habits. The time to digest and absorb the food is reduced if we eat products rich in water such as fruits, vegetables and others.