Small intestine.

• • Tube that is 12 feet long (3.6 metres)​
• Functions:​

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  • Absorbs nutrients in to the blood​
  • Food stays in your small intestine for 4 to 8 hours​
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• The duodenum's primary function is to begin the digestive process of breaking down and absorbing nutrients needed by the body.
• The primary function of the jejunum is to absorb sugars, amino acids, and fatty acids
• The ileum is the final portion of the small intestine, measuring around 3 meters, and ends at the cecum. It absorbs any final nutrients, with major absorptive products being vitamin B12 and bile acids.
• • The small intestine is adapted for absorption as it is very long and has a highly folded surface with millions of villi (tiny, finger-like projections)​
  • These adaptations massively increase the surface area of the small intestine, allowing absorption to take place faster and more efficiently​​(same adaptions as alveoli)
• • Peristalsis helps by mixing together food and enzymes and by keeping things moving along the alimentary canal​