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Composition and function of Gastric Juice
March 24, 2011 by:
krishnaverma Points: 12
Category: General Science
In this resource I will explain the composition and function of Gastric Juice.
Gastric Juice is secreted daily by special secretory glands in the mucosa. It consists of:
6.Inactive Enzyme Precursors
Composition of Gastric Juice
The average composition of human gastric juice is as follows:
1)Total Quantity: About 500-600 ml per meal (1200 ml-1500 ml per day).
3)Total Solids: 0.55%.
4)Inorganic: 0.15% (NaCl, KCl, CaCl2, Calcium phosphate, Magnesium phosphate, Bicarbonate, etc.).
b)Other proteolytic enzymes of the gastric juice which are Cathepsin, Gastricin
e)Other gastric enzymes are present in minute amounts and are Lysozyme, Gelatinase,
6)Nature: Strongly acidic.
7)Free HCl: 0.4-0.5%
8)Total Acidity: 0.45-0.6%, it includes free HCl, as well as HCl combined with proteins. It also includes other acids, such as lactic acid. As ordinarily examined, the gastric contents show a lower acidity (0.15% to 0.25% HCl), because the HCl is partly neutralized by mucin and other substances.
9)pH - 0.9 - 1.5
10)Specific Gravity - 1.002 - 1.004
11)Freezing Point - 0.59oC
Functions of Gastric Juice
Various functions of gastric juice are:
1)Water helps in the liquefaction of the food swallowed.
i)Helps in acidifying the food
ii)It stops the action of salivary amylase.
iii)It also Kills ingested microbes.
iv)Helps in the effective digestion by pepsins by providing an acid environment.
3)Hydrochloric acid convert Pepsinogens to pepsins. Pepsins help in the digestion of proteins by breaking them into smaller molecules.
4)Intrinsic factor assists in the absorption of vitamin B12 from the ileum.
5)Mucous lubricates the contents of stomach walls providing it safety against mechanical injury.
6)Gastric acid acts as a barrier between the stomach wall and the corrosive gastric juice. This provides safety from chemical injury.
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