Digestive Sysytem
Digestive system consists of organs which break down the food we eat into smaller particles. Digestive system is otherwise called alimentary canal.
Alimentary canal
This is a long tube which begins from the mouth and ends at the anus. It has various organs attached to it. This includes;
· Mouth
· Tongue
· The stomach
· Small intestine
· Large intestine
Digestion
This is the breaking down of food into simpler particles which can be absorbed by the body.
Digestion of Food in the Body
The food substances are ate, chewed and mixed with saliva at the mouth. The salivary juice partially digests the food (starch) before the gullet pushes it down into the stomach. The stomach wall then secretes the gastric juice which continues the digestion process. The partially digested food then moves into the small intestine where different digestion juices are secreted to digest specific food substances. The digested part of the food would then diffuse into the blood stream. The undigested food moves to the large intestine where it is stored.
Food and their End Products
|
Food |
End product |
|
Carbohydrate |
Glucose |
|
Protein |
Amino acid |
|
Fat and oil |
Fatty acid and glycerol |
Food Absorption
The end product of digestion is capable of passing through the wall of the small intestine into the blood stream. This happens through a structure called villa. The process by which the digested food diffuses through the villa into the blood stream is called absorption.
Function of Digestive Enzymes
The tooth: The function of the tooth is to break the food substance into smaller particles.
Description of Tooth Parts
· Enamel: It is the hard layer which protects the inside of the tooth
· Dentine: It is next to enamel; it is soft and contains living cells.
· Pulp: It is next to dentine: It also contains cells which keep the tooth alive.
· Jaw Bone: It helps to holds the tooth.
Tests and Exercises
1. The process by which the digested food diffuses through the villa into the blood stream is called (a) Digestion (b) Absorption (c) Ingestion (d) Elimination Answer: Absorption
2. The end product of protein is called (a)Amino acid (b) Glucose (c) fatty acid and glycerol (d) None of the above Answer: Amino Acid
3. The process by which food is digested from the mouth to esophagus or gullet is called (a) Peristalsis movement (b) Digestion movement (c) Ingestion movement (d) None of the above. Answer: Peristalsis movement
4. Which tooth part contains the cell that keeps the tooth alive? (a) Pulp (b) Dentine (c) jawbone (d) Enamel Answer: Pulp
5. The digested system is also referred to as (a) Digestive canal (b) Alimentary canal (c) Food canal (d) peristalsis canal Answer: Alimentary canal.
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