absorption

• what is the ileum specially adapted for?


  to maximise the efficiency of absorption of crucial nutrients through its surface and into the blood stream.
• what are the adaptations of the ileum?


  villi and microvilli for large surface area and the walls are very thin to reduce diffusion pathway.
• what powers the villi?


  the villi is powered by muscle
• what does the muscle that powers the villi cause it to do?


  the muscle makes a sweeping motion that moves food along the ileum, it constantly replaces the food its drawn nutrients from with new nutrient rich food.
• what is crucial for absorption?


  the contact with a blood supply, the villi is surrounded by lots of blood vessels to constantly remove the absorbed nutrients, maintaining a concentration gradient.
• what are the layers of the villi? top to bottom.

  1. mucosa
  2. submucosa
  3. muscularis
• what is absorbed by the ileum through diffusion and co-transport?


  glucose and amino acids.
• what do bile salts do?


  bile salts emulsify larger lipids unto tiny micelle droplets so that lipases can then more efficiently get at the lipid molecules to break them into monoglycerides and fatty acids chains.