The Mammalian Digestive System

The digestive system in mammals is responsible for the chemical breakdownof food and its absorption from the gut

Much of the food that we consume contains macromolecules that are too large to be absorbed and utilised by the body cells

Starch and protein are polymers andlipids are large molecules

Polymers need to be broken down into their monomers and large molecules into smaller

constituents, if absorption is to occur

The Mammalian Digestive System

In humans, hydrolytic enzymes are responsible for the chemical digestion

of starch, protein and lipids

Digestion is the process of breaking down large food molecules into smaller molecules that can be

absorbed and used by body cells

Hydrolytic enzymes (hydrolases) aremanufactured in various regions

of the digestive system

The Mammalian Digestive System

The organs of the digestive system are made up of the gastrointestinal tract (GI)

and accessory structures

The gastrointestinal tract or alimentary canal is a continuous tube running from the mouth to the anus

The major organs of the alimentary canal are:

• The mouth• The oesophagus• The stomach• The small intestine (duodenum and ileum)• The large intestine (colon, rectum and anus)

Mouth

Salivary glands

Oesophagus

Stomach

Small intestine(duodenum + ileum)

Liver

Colon

RectumAnus

Pancreas (in loop of duodenum)

The Stomach & Duodenum Outlinedon a Barium Meal X-Ray

StomachStomachDuodenumDuodenum

The Stomach & Intestine Outlinedon a Barium Meal X-Ray

StomachStomach

IntestineIntestine

OesophagusOesophagus