Tuesday, 8 April 2014

Stomach- Choon Wee & Afif

  • Stomach 
    • Type of digestion : 
    • Chemical
    • Enzymes
      • Pepsin
        • Digest proteins

        • Product : Polypeptide
    • Processes that take place in the stomach 
      • Presence of food causes the gastric glands to secrete gastric juice into the stomach cavity
      • Peristalsis in the stomach wall churns and breaks up the food.
        Peristalsis also mixes the food well with gastric juice
      • Acid stops the action of salivary amylase by denaturing it
      • Changes the inactive form of the enzyme pepsinogen, in the gastric juice to the active form called pepsin 
      • Acid kills certain potentially harmful micro organisms in the food. 
      • Stomach has a mucus layer that protect the stomach wall from the acid 
      • *Renin that 'curdles' the substance so that there would be more time for digestion 
    • Adaptation 
      • Thick well developed muscular walls
      • Stomach wall has numerous pits which leads to gastric glands that secretes gastric juice 
      • There is a ring of muscle called the pyloric sphincter located at the place where the stomach joins the small intestine. When this ring contracts, the entrance to the small intestine closes. 

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