Quartz 4

Processes that take place in the stomach

1 min read

  • Presence of food in the stomach → simulates gastric glands to secrete gastric juices into the stomach cavity

  • Peristalsis in stomach wall → churns and breaks up the food (SA to V concept) + also helps to mix gastric juice with the food well.

  • Gastric juice in stomach → contains hydrochloric acid (HCl) and a protease (pepsin).

    • Hydrochloric acid
      • Stops action of salivary amylase by denaturing it (Enzymes)
      • Provides low pH environment within stomach (pH2) → which is optimum pH for proteases in stomach to digest proteins. (pepsin) (refer to Acids)
      • Kills certain potentially harmful microorganisms in food

  • Protease → digest proteins into polypeptides

    • Proteins → Polypeptides

  • mucus layer → protects stomach wall against being digested by enzymes it produces, as well as HCl

  • Also moistens the food to allow easy movement within the stomach

  • food normally remains in stomach for 3-4 hours. partly digested food - becomes liquified - forming chyme

  • chyme passes in small amounts into the duodenum → when pyloric sphincter relaxes and opens.

without stomach - person may not feel hungry.

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