Question

What is Digestion, absorption, and assimilation?

Answer 1

Digestion:

1. Before the body can use the food, it has to be first absorbed by the bloodstream.
2. This is done by breaking the large, insoluble food molecules into smaller, soluble ones by the process of digestion, which is performed by the digestive system.
3. Digestion is a mechanical and chemical breakdown of food into small organic fragments.
4. Mechanical digestion referred to the physical breakdown of large pieces of food into smaller pieces that can subsequently be accessed by digestive enzymes.
5. In chemical digestion, these enzymes break down food into small molecules that the body can use.
6. Relevant organs are the mouth and teeth, alimentary canal, stomach, and duodenum.

Absorption:

1. A simple product of digestion is small enough to be absorbed by the epithelial cells of the intestinal villi.
2. Each day the alimentary canal processes up to 10 liters of food, liquids, and GI secretions, also less than one liter enters the large intestine.
3. Almost all ingested food, 80% of electrolytes, and 90% of water are absorbed in the small intestine.
4. Although the entire small intestines are involved in the absorption of water and lipids, most absorption of carbohydrates and proteins occurs in the jejunum.
5. The small intestine is very highly efficient at this, absorbing monosaccharides at an estimated rate of 120 grams per hour.
6. Especially, bile salts and vitamin B12 are absorbed in the terminal ileum.

Assimilation:

1. It is the movement of the digested food molecules into the cells of the body from where they are used.
2. The liver is important in assimilation
3. For example, glucose is used in respiration to provide energy, and also amino acids are used to build new proteins.
4. The fate of the absorbed food glucose for energy production, amino acids for building up body materials, and fats for energy reserve.