Human digestion is the process by which your body breaks down food into the necessary nutrients and energy it needs to function. Human digestion is necessary in order to get the food eaten to be useful to the human body. In order to understand how human digestion works, you have to understand the general concept of the human digestive system.
How human digestion works
Without human digestion, most of the nutrients the body will need to grow will not be provided, and undigested food can actually become a serious complication if necessary measures are not taken.
WHERE EXACTLY DOES HUMAN DIGESTION START?
Human digestion generally begins with the intake of food into the mouth or oral cavity where it is being acted upon by chemical and mechanical digestive processes. The human teeth begin the mechanical process of grinding and breaking down the food, while the saliva secretes an enzyme known as amylase to chemically break down carbohydrates.
After food is swallowed, this chewed food (or bolus) goes down to the esophagus. The esophagus can be described as a long tube connecting the mouth and the stomach. The bolus enters the stomach and is being acted upon by more chemical and mechanical digestive processes.
The stomach muscles are responsible for churning the bolus to mix with different digestive enzymes and gastric acids which the stomach secretes. These different processes turn the bolus into a liquid known as chyme.
Afterward, the stomach continues digestion for long hours during which a particular enzyme known as pepsin breaks down the protein content of the food. The chyme is then transported into the small intestine where more important chemical digestion takes place.
The liver contains bile which is now released from the gallbladder to assist in digesting fats. Additionally, pancreatic enzymes and other intestinal enzymes add up with the chyme to further human digestion.
All needed nutrients are absorbed by the walls of the small intestine into the body’s circulatory system leaving behind water and undigested materials.
The chyme then enters the large intestine where the water component is extracted and certain human bacteria break down some of the undigested material to produce needed vitamins for the body.
It is no news that the remaining undigested material is what is popularly known as feces, which further goes through the rectum and out of the body through the anus.
HOW EFFECTIVE DOES THE HUMAN DIGESTION WORK?
The human gastrointestinal tract is very good at collecting nutrients. For example, the human body produces about 1.5 liters of saliva per day and up to 2 liters of gastric secretions per day, which indicates that the human body is exceptionally efficient at absorbing physiological fluids.
All except roughly 100 mL of water is absorbed back into the body, giving an absorption efficiency of up to 97%.
The human body is still very effective in digesting and absorbing meals. The human gives off roughly 50 g of solid waste that must be expelled on average. Dead intestinal cells, insoluble carbohydrates (fiber and whole grains), and bacteria make up the majority of this excretion substance.