3.3.3 Digestion

Digestion

The process of hydrolysing large, insoluble molecules into smaller, soluble molecules for transport and assimilation.

Physical Digestion

The mechanical breakdown of large molecules into smaller ones, such as through the action of teeth and stomach churning.

Chemical Digestion

The enzymatic breakdown of larger insoluble molecules into smaller molecules.

Salivary Glands

Glands in the mouth that secrete amylase to hydrolyse starch into maltose.

Oesophagus

The muscular tube that transports food from the mouth to the stomach via peristalsis.

Stomach

A muscular sac that produces enzymes and hydrochloric acid for digesting and storing food, especially proteins.

Duodenum

The first section of the small intestine where pancreatic and gall bladder enzymes are introduced.

Pancreas

A large gland that secretes proteases, lipase, and amylase for digestion.

Gall Bladder

A small pouch that stores bile produced by the liver.

Ileum

The long section of the small intestine where digestion continues and absorption occurs through villi and microvilli.

Large Intestine

The part of the digestive system that absorbs water from indigestible food.

Rectum

The storage area for faeces before excretion.

Salivary Amylase

An enzyme that hydrolyses starch into maltose in the mouth.

Pancreatic Amylase

An enzyme that continues the hydrolysis of starch into maltose in the small intestine.

Maltase

An enzyme in the ileum that hydrolyses maltose into alpha glucose.

Peptidases/Proteases

Enzymes that hydrolyse proteins into smaller peptides and amino acids.

Endopeptidases

Enzymes that hydrolyse peptide bonds within protein molecules.

Exopeptidases

Enzymes that hydrolyse peptide bonds at the ends of peptide chains.

Dipeptidases

Enzymes that hydrolyse dipeptides into single amino acids.

Lipases

Enzymes that hydrolyse lipids into monoglycerides and fatty acids.

Bile Salts

Compounds produced by the liver that emulsify lipids to increase surface area for lipase action.

Micelles

Structures formed from monoglycerides and fatty acids that facilitate absorption across the intestinal lining.

Villi

Projections in the small intestine that increase surface area for absorption.

Epithelial Cells

Cells in the intestinal lining that have many villi and mitochondria for efficient absorption.

Monosaccharides

Simple sugars like glucose, galactose, and fructose absorbed through different mechanisms.

Chylomicrons

Lipoprotein particles formed from triglycerides, cholesterol, and proteins that transport lipids in the bloodstream.