Download DIGESTION in SMALL INTESTINE - INTESTINAL

DIGESTION in SMALL INTESTINE INTESTINAL DIGESTION
3 juices help digestion in the duodenum of
small intestine :
1) BILE JUICE :
secreted from the liver , contains
dissolved bile salts which emulsified fats
i.e dividing large masses of fats into
small globules to increase its surface area
for the enzymatic action .
2) PANCREATIC JUICE :
includes
a. Sodium bicarbonate
neutralize HCl , keeping the medium
alkaline PH 8 to activate digestive
enzymes
b. Pancreatic Amylase LIVER and PANCREAS
Glycogen and Starch + water ........
Pancreatic Amylase ...... Maltose (
Disaccharide )
c. Trypsinogen
the inactive trypsinogen ...... Co enzyme
Enterokinase ....... active trypsin
Protein + Water ......... Trypsin ........
Polypeptides ( Peptones )
d. Lipase
Emulsified fats ............ Lipase
.......... Fatty acids + Glycerol
3) INTESTINAL JUICE :
complete the action of previous enzymes and
end digestion :
a. Peptidases : number of enzymes
Polypeptides ............ Peptidases
............ Amino acids
b. Maltose sugar .......... Maltase enzyme
.......... 2 molecules of glucose
Sucrose ( cane sugar ) ....... Sucrase
enzyme ( invertase ) ...... Glucose +
Fructose
Lactose ( milk sugar ) ........ Lactase
enzyme ......... Glucose + Galactose
c. Enterokinase , not digestive enzyme but
acts as Co enzyme which activates the
inactive
trypsinogen enzyme to the active trypsin .
ABSORPTION
is the transfer of the digested food to the
blood and lymph through the epithelial
cells , the Mucosa of the ileum , by
membranal diffusion and active transport .
Villi
are folds and convolutions forming tiny
finger like projections in the inner
epithelial lining of the ileum , increasing
surface area to absorb food , 10 meters
square = 5 times as surface area of the
body .
Structure of a Villus :
Outer covering of single epithelial cells ,
encloses lacteal vessel surrounded by
network of arterial and venous blood
capillaries extend from submucosal layer .
Some Microvilli ( tiny projections ) come
from epithelial cells of villi increasing
absorbing surface .
Structure of Villi