Small intestine

• Body's major digestive organ
• Longest portion of the alimentary tube (2-4m/7-13ft)
• Site of nutrient absorption in the blood
• Muscular tube extends from the pyloric sphincter to ileoceal valve
• Suspended from the posterior abdominal wall by the mesentery
• 3 subdivisions:

  -Duodenum

  -Jejunum

  -Ileum
• Most chemical digestion happens in small intestine
• Intestinal enzymes: break complex surgers into simple surgers
• Intestinal enzymes: compleet some protein digestion
• Pancreatic enzymes: major role in digesting fats, protiens, and carbs
• Structural modificatiosn: increase surface area fr food absorption
• Structural modification: decrease in number toward the end of small intestine
• Villi: finger-like prjections formed of the plasma membrane (brush border enzymes)
• Circular folds: deep folds of mucosa and submucosa
• duodenum


  first part of small intestine
• jejunum


  second part of the small intestine
• ilium


  last section of the small intestine, connects to the cecum of the large intestine