Question

What are the different stages of digestion?

Answer 1

The gastrointestinal tract is a tract beginning at the mouth and ending at the anus. It is also called the alimentary canal or the digestive tract.

Complete Answer:
The human gastrointestinal tract is divided into the upper gastrointestinal tract and lower gastrointestinal tract. The gastrointestinal tract is also divided into the foregut, midgut and hindgut. The gastrointestinal tract is about 9 meters in length but is considerably shorter when observed in the human body as the intestines maintain tension and distension for peristalsis.
The act of digestion in the body involves six main processes. They are:
1. Ingestion
2. Propulsion
3.Mechanical digestion
4. Chemical digestion
5. Absorption
6. Defecation
Ingestion refers to the entry of food into the alimentary canal after passing through the mouth.
Propulsion is the act of swallowing the food that enters the alimentary canal.
Mechanical digestion is the process of digestion that does not change the chemical nature of food. It changes the physical attributes of the food.
Chemical digestion is the breakdown of food with the help of digestive enzymes in the small intestine.
Absorption is the process of assimilation of broken down food into the bloodstream by absorbing the nutrients of the food.
Defecation is the removal of waste from the body in the form of feces.

Note:
The gastrointestinal tract contains many microbes. There are an estimated 4000 strains of bacteria that influence the metabolism of the body. The cells of the gastrointestinal tract secrete enzymes like gastrin, secretin, cholecystokinin and ghrelin to regulate the process of digestion.
The gastrointestinal tract includes all the organs present in the digestive system of humans. The food is ingested through the mouth. The nutrients are extracted from the food and energy is absorbed. The waste is expelled out through the anus as feces. The major parts of the gastrointestinal tract are:
1. Mouth
2. Oesophagus
3. Stomach
4. Intestines
5. Anus