Digestive System Physiology

Human body consists of different complex systems. One of the most important of such systems is digestive system. Food is broken down into energy by means of this process. The body, for proper functioning, consumes the energy released in this process and ejects toxins out.

There are five major steps of digestive system:

Ingestion, Secretion, Digestion, Absorption, and Excretion.


The first and foremost step of the digestion process is the intake of the food. The ingestion of food is done by the help of mouth. It is the opening through which food enter into the body. Mouth functions as a channel through which food enters into the stomach.


The body starts releasing important secretions from different organs as soon as one intakes food. The first fluid, which acts upon food, is saliva. It begins the digestion of the carbohydrates by moistening the dry food material. Then Mucus performs its function as a lubricant in the GT track. With the help of mucus, food easily passes into the stomach. HCL fluid is produced in the stomach. It helps in chemical digestion of the food and the killing of harmful bacteria that enters into the body with food. Then other important enzymes help breaking up the complex particles of proteins, lipids, and carbohydrates into smaller components.


There are two types of digestion: mechanical and chemical. Mechanical digestion refers to the process of physical breakdown of the large pieces of food into smaller partials for easy digestion. Mechanical digestion in the conversion of complex compounds of food into simple components for easy absorption. Mechanical and chemical digestion begin at the very moment the food enters the body and continue till its excretion.  Most of the chemical digestion takes place in small intestine. While in the stomach, food is reacted with the effective pancreatic juice which digest carbohydrates, lipids, nucleic acids and protein. In the duodenum, food is converted into the chemical building blocks which are fatty acids, amino acids, monosaccharide, and nucleotide.


Absorption takes place after the food is converted into chemical building blocks. Absorption take place at stomach. Stomach and intestine have semi-permeable walls through which the food transfers into the bloodstream. Most of the absorption of the chemicals happens in small intestine.


It is the final stage of the digestion process in which waste products and toxics substances are released from the body. When all the necessary chemicals are absorbed from the food, it turns into feces. Feces are full of waste products and toxic chemicals which must be ejected from the body by the anal canal.

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