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Process of Absorption and Transportation of Digested Food and Defecation
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The wall of small intestine has millions of fine projection called villi which increases the surface area for the process of digested food.
Villi on the walls of the small intestine
- Wall of the villus is very thin. It is one-cell thick to increase the rate of absorption
- The surface of small intestine has many folds to add to the surface area and increase the absorption rate of the products of digestion
- The function of the blood vessels in the small intestine is to transport nutrients to all parts of the body
Process of Transporting the Products of Digestion
- The molecules that are absorbed into the villus will undergo assimilation.
- Assimilation is a process of distributing the end products of digestion for the use of the cells in our body
- Our body uses the end products of digestion as follows:
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Glucose is used to produce energy
Amino acid is used to form component of cells
Fatty acid and glycerol combine to form fat which is used as heat insulator and to protect internal organs
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Defecation
- Food that is not absorbed by the small intestine will move into large intestine
- While moving, water and minerals are reabsorbed into the blood stream
- This makes the food to become solid waste called faeces
- Faeces are stored temporarily in the rectum before eliminated through anus
- The process of elimination of faeces from the body is called defecation
