Digestion and Absorption

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(CCK) & gastric inhibitory peptide (GIP).

1). Gastrin, produced by

intestine, acts on gastric

glands and stimulates

the secretion of HCl and

pepsinogen.

2). Secretin stimulates the

secretion of bicarbonate

ions rich pancreatic fluid.

(NEET II 2016)

3). CCK, secreted from

duodenum cause of

contraction of gall bladder.

4). GIP inhibits gastric

secretions and motility

ÅBSØRPTÏØÑ ØF DÏGËSTËD PRØDÜÇTS

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Absorption is the transfer of end products of digestion through the

intestinal mucosa into blood & lymph. It is of 2 types- passive and active.

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Passive absorption (Passive transport): Absorption of nutrients from

higher concentrated region to lower concentrated region without the

expenditure of energy. It includes osmosis (absorption of water) and

diffusion (absorption of solute molecules).

DIFFUSION IS 2 TYPES:

Simple diffusion In this, molecules alone can be diffused. E.g. small

amounts of monosaccharides like glucose, amino acids, vitamins,

electrolytes like chloride ions etc.

Facilitated diffusion Diffusion with the help of carrier proteins. E.g.

glucose, fructose etc.

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Active absorption (Active transport): Absorption of nutrients from

lower concentrated region to higher concentrated region (i.e. against

concentration gradient). It needs energy. E.g. absorption of amino acids,

monosaccharides like glucose, electrolytes like Na⁺ etc.

ÅBSØRPTÏØÑ ØF LÏPÏDS

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Monoglycerides, diglycerides and fatty acids cannot be absorbed

directly as they are insoluble in water.

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Bile salts and phospholipids convert them into small spherical water-

soluble droplets called micelles.