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A Handbook of Biology

Intestinal glands : Simple tubular glands are of 2 types:

Consists of mucus-secreting goblet cells and antibacterial enzyme

secreting paneth cells. (NEET 2017)

CRYPTS OF LIEBERKUHN

Confined to submucosa of duodenum. Secrete mucus only.

(NEET 2019)

BRUNNER’S (DUODENAL) GLANDS

DÏGËSTÏØÑ ÅÑD ÅBSØRPTÏØÑ ØF FØØD

Digestion is the conversion of complex insoluble food materials into

simple and absorbable form. It includes mechanical processes such as

mastication (chewing), deglutition (swallowing) & peristalsis (wave-like

movement of food bolus through the gut by muscular contraction).

Intestinal glands secrete alkaline intestinal juice (succus entericus).

It contains enzymes (maltase, lactase, sucrase, dipeptidase, lipases,

nucleotidases, nucleosidases etc).

The bicarbonate and mucus provide alkaline medium and protect

intestinal mucosa.

Digestion in buccal cavity: Only starch

digestion. Ptyalin converts starch

(polysaccharide) into disaccharides. About 30%

of starch is digested by ptyalin.

Starch

Maltose

Isomaltose

Limit

dextrins

Salivary amylase

pH 6.8

Digestion in stomach: The gastro –

Oesophageal sphinter controls the passage

of food into the stomach. The Stomach stores

food for 4-5 hrs. It is mixed with gastric juice

by the churning movements and is converted

into acidic pasty form (chyme).