Role of Pancreas and liver in digestion and what is Gall bladder
Role of Pancreas in digestion:
Pancreas lies
ventral to the stomach and has both endocrime and exocrime function. Exocrime
cells in the pancreas secrete digestive enzymes into pancreatic duct, which
merges with hepatic duct from the liver to form common bile duct that enters
the duodenum.
Pancreatic
enzymes complete the digestion of carbohydrates and proteins and initiate the
digestion of lipids.
Trypsin
carboxypeptidaze and chymotrypsin digest protein into smaller peptide and amino
acids. Lipases convert triglycerides into smaller glycerol and free fatty
acids. Amylase converts polysaccharides into disaccharides and monosaccharides.
The pancreas also secretes bicarbonate (HCO-3) ions that help neutralize the
acidic food residue coming from the stomach. Bicarbonate raises the pH from 2
to 7 for pancreatic enzymes to work.
Role of liver in digestion:
Liver: The
largest organ in mammalian body is just under the diaphragm. In the liver
millions of specialized cells called hepatocytes take up nutrients absorbed
from the intestines and release them into bloodstream. Hepatocytes also
manufacture blood protein prothrombin and albumin. Liver removes amino acids
from organic compounds. Liver forms urea from proteins and conversion of excess
amino acids into urea to decrease body levels of ammonia. Liver work in
synthesis of nonessential amino acids and conversion of galactose and fructose
to glucose and oxidation of fatty acids. Liver works in conversion of carbohydrates
and proteins into fat.
Liver makes
modification of waste products, toxic drugs and poisons and synthesis of
vitamin A from carotene with the kidney, participation in activation of vitamin
D.
Liver
manufactures bile salts used in the small intestine for emulsification and
absorption of simple fats, lipids and lipo protein liver stores glucose in the
form of glycogen and stores fat soluble vitamin A, D, E and K and minerals such
as iron from the diet.
Gall bladder:
It is greenish
yellow small organ lying near liver. Gall bladder stores greenish fluid called
bile that the liver cells continuously produce. Bile is very alkaline and
contains pigments, cholesterol, lecithin, mucin, bilirubin and bile salts that
act as deterens to emulsify fats (from them into droplets suspended in water)
and aid in fat digestion and absorption. Bile alts also combine with the end
products of fat digestion to form micelles. Micelles are lipid aggregates
(fatty acid and glycerol) with a surface coal of bile salts. Because they are
so small, they can cross the microvilli of intestinal epithelium.
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