small intestines

small intestines

1. Narrow (3cm) but long (6cm)

   • 21 feet

2. 3 Major segments:

   • Duodenum
     • Jejunum
       • Ileum
         • Lympth nodules i Ileum mucosa/submucosa = Peyer's Patchers. Defends against microorganisms ingested.
           • Ileocecal Junction - where SI meets LI spincter & valve present to ensure one way flow
       • decrease diameter, thickness of internal wall, & number of fold & projections farther away from stomach. Major site for nutrient absorbtion.
     • curves to the left, head of pancreas sits in curve 2/3 way down depending parts are 2 small mounds, Major & minor duodenal papillae = openings to ducts from liver & pancreas, Folds & projection in mucosa/submucosa - increase surface area 600 fold for better digestion/absorbtion

3. digested food is pushed through the SI by PERISTALSIS

4. Villi -

   • Fingerlike projection with the lining of the SI that are involved in absorbing digested material into the bloodstream

5. Carbohydrate, Fats and proteins are absorbed here

6. associated with PANCREAS & LIVER

7. Functions

   • Major site for DIGESTION of food Absorbtion of nutrients/vitamins Removal of water from ingested fluids
   • Major site for DIGESTION of food, Absorbtion of nutrients/vitamins, removal of water from ingested fluids

8. Majority of absorbtion of nutrients into bloodstream

9. fat digestion occurs here

10. Mucosa of SI produces secretions

    • Primarily water, electrolytes & mucus
      • Lubricates
        • Protects SI wall from acidic chyme & digestive enzymes
          • Muscle in muscular contract to mix & move chyme through SI
            • Takes 3-5 hours pass from stomach - LI

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