The specialized features of the small intestine that enable efficient absorption of digested food include villi and microvilli. The villi are finger-like projections lining the ileum that are richly supplied with blood capillaries and lacteals. The microvilli further increase the absorptive surface area. Sugars, amino acids, and fatty acids are absorbed into the bloodstream or lacteals by diffusion or active transport. Fats are recombined into lipoproteins within the villi and transported to the bloodstream.
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What specialised feature of small intestine account for
1. What specialised feature of small
intestine account for efficient
absorption of digested food stuffs.
2. Parts of small intestine
• 3parts
• 1/duodenum
• 2/ jejunum
• 3/ ileum.
• Duodenum leads to jejunum and then to
ileum
3.
4.
5. When chyme reaches small intestine
• When chyme reaches duodenum, its acidity
causes release of enzymes from pancreas,
liver and duodenal cells.
6. Absorptive function of jejunum
• Jejunum is second portion of small intestine.
• Its length is about 2.4 metres.
• 2/5th of small intestine is jejunum.
7. Absorptive function of ileum
• Nearly all absorption of products of digestion
takes place in ileum.
• The internal(inside)
• surface of ileum has many folds.
• These are velvety in appearance due to the
presence of villi.
• Villi are finger like projections/outgrowths.
8.
9.
10.
11. villus
• Each villus is richly supplied by blood
capillaries and lacteal.
• Lacteals a vessel of lymphatic system with a
covering of epithelial cells.
• Each villus has countless microvilli which can
only be seen by electron microscope.
• These are closely packed cylindrical processes
which form brush border .
12. Functions of villi
• Due to these villi and micro villa, absorptive
surface becomes incredibly large.
13. Absorption of sugars and amino acids.
• By diffusion
• By active transport
• Sugars and amino acids are absorbed into
blood stream.
14. Absorption of fatty acids and glycerol
• They enter the epithelial cells of villi and
recombine in to fats.
• These fats enter lacteals.
• There are proteins in lacteals.
• These protein meet up with fats and form lipo
proteins
• These lipoproteins enter blood stream via
thoracic lymphatic duct.
15.
16. lipoproteins
• These lipoproteins go to blood and enzymes in
plasma (part of blood) hydrolyse them.
• After that they can enter body cells.
• These hydrolysed lipo proteins can be used in
respiration(breathing) or can be stored in liver
and under the skin as fat.
17. • Contents of intestine are pushed along
digestive tract by peristaltic activity.
• At the end of ileum where there is ileo caecal
valve .
• Contents enter large intestine through this
valve/sphincter.
