GASTROINTESTINAL SYSTEM

overiew of digestion

  • digestion → breakdown of large insoluble molecules into smaller soluble molecules than can be absorbed into the blood

  • nurtients that are broken down release chemical energy that organisms need

  • food is broken down chemically and or mechanically ← this is done by either the gastrointestinal/digestive tract

nutrients

  • major nurtient classes are proteins, lipids, carb

    • also require vitamins and mineral nurtients

vitamins :

  • chemically unrelated molecules w diverse functions ( solubity is vital )

  • water soluble vitamins - excrted in water

  • lipid soluble vitamins - stored in fat

mineral nutrients

  • metallic elements involved in various mechanisms

  • transported into the body via channels, carriers and pumps

major nutrients

nutrient transport

evolution of gasintestintal

-most aniamls use an inner lumen lined with epithelial cells to digest

  • simple organisms use phagocytosis

  • aquatic organisms can absorb food across outer ephthelial layer

  • isolating food in an internal chamber - can be flooded with digestive enzymes can allow many foods to be broken down

  • next part - is to ensure theres a structure that has 2 ends → there was a shift from one end to 2 ends

major functions of gasintestinal rract

major regions