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Structure of Ileum:

Absorption of triglycerides:

The ileum is adapted to the function of absorbing the Once formed during digestion, monoglycerides and fatty acids remain in association with the bile salts that initially
emulsified the lipid droplets
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products of digestion
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They have thin walls lined with epithelial
cells on the other side of which is a rich network of
blood capillaries
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Through the movement of material within the lumen of the ileum, the micelles come into contact with the epithelial
cells lining the villi of the ileum
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As these are non-polar molecules, they
easily diffuse across the cell-surface membrane into the epithelial cells
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Villi are situated at the interface between the lumen Starting in the EPR and continuing in the Golgi apparatus, the triglycerides associate with cholesterol and lipopro(cavity) of the intestines and the blood and other tis- teins to form structures called chylomicrons (special particles adapted for transport of lipids)
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Chylomicrons move out of the epithelial cells by exocytosis
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From here, chylomicrons pass (via lymphatic vessels) into the blood stream
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Thin walled = reduced diffusion distance
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Contain muscle so they are able to move =
movement mixes contents of the ileum which
helps maintain a diffusion gradient
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Well supplied with blood vessels = blood can
carry away absorbed molecules and hence maintain diffusion gradient
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Absorption of amino acids and monosaccharides:

The method of absorbing amino acids and monosaccharides is the same, namely through cotransport and diffusion
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The other
end is soluble in water (hydrophilic) but not in fat
(lipophobic)
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In this way they prevent fat droplets from sticking to
each other and forming large droplets leaving only tiny
ones (micelles)
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