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the digestive system
LC Biology
Term | Definition |
---|---|
ingestion | food is taken into the alimentary canal |
digestion | food is broken down into smaller soluble pieces |
absorption | the movement of digested food from the alimentary canal into the blood system |
egestion | Removal of unabsorbed material as faeces |
mechanical breakdown of food involves | 1) teeth 2)contractions in stomach wall 3)peristalsis |
peristalsis | Rhythmic muscular contraction and relaxation in the wall of the alimentary canal causing the food to move along the canal |
incisors | job=cutting |
canines | job= tearing |
Pre Molars and Molars | job=crushing and grinding |
Human dental formula | 2(i2/2 C1/1 Pm 2/2 M 3/3) |
oesophagus | -connects pharynx to stomach -food moves down the this by peristalsis |
stomach | stores food for four hours |
Chyme | mixture of food and gastric juices formed in the stomach |
functions of gastric juice | -mucus -HCL -Pepsin |
mucus | function= lines and protects the stomach wall |
HCL | function= kills bacteria in food and activates pepsinogen |
pepsinogen | HCL coverts this to the active enzyme. this enzyme digets protein |
small intestines parts | duodenum jejunum ileum |
duodenum | function- most digestion takes place here |