Functions of The parts of the digestive system

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  • Parts of the digestive system.
    • 1 Oesophagus
      • Tube taking food from mouth to stomach.
      • Uses muscle contractions called peristalsis
      • Mucus is secreted from tissues in the walls to lubricate foods passage
    • 3 Small instestine
      • Has two main parts - duodenum and ileum.
      • Chyme is moved along the small instestine by peristalsis
      • Bile ( alkaline) and pancreatic juice neutralise the acidity of the chyme and breaking it down in to smaller molecules
      • Ileum- small soluble molecules ( glucose and amino acids) are absorbed through villi in gut wall.
      • Molecules are absorbed by diffusion, facilitated diffusion and active transport.
    • 4 Large intestine
      • absorbs water salts and minerals
      • Has folded wall ( large surface area for absorption)
      • Bacteria that decompose some of the undigested nutrients are found here.
    • 2 Stomach
      • is a small sac with lots of folds so it can expand ( can hold up to 4ltrs of food/liquid)
      • Entrance and exit of the stomach is controlled by sphincter muscles
      • stomach walls produce gastric juice - helps break down food. It consists of hydrochloric acid pepsin ( enzyme and mucus)
      • Pepsin hydrolyses proteins in to smalled polypeptide chains
      • Only works in acidic conditions ( provide by HCl.
      • Peristalsis of stomach turns food into an acidic fluid called chyme
    • 5 Rectum
      • Faeces are stored here
      • Faeces then pass through the sphincter muscles at the anus during defecation.

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