• Components of the digestive system• The alimentary canal• Digestive glands• Human digestive system• The digestive system of a rat• Peristalsis• The structure and functions of a villus

a tube from mouth to anusa tube from mouth to anus

The digestive system in mammals

Alimentarycanal

Alimentarycanal

Digestive glands

Digestive glands

they produce enzymes for digestion

they produce enzymes for digestion

The alimentary canal

oesophagus

stomach

small intestine

large intestine

rectum

anus

Digestive glands

• salivary glands

• gastric gland

• liver

• pancreas

• intestinal gland

salivasaliva

bilebile

gastric juicegastric juice

pancreatic juicepancreatic juice

intestinal juiceintestinal juice

Human digestive system

Digestive system of a rat

large intestinesmall intestine

liverstomach

Peristalsis

• muscle in front of the food bolus relaxes

• muscle behind the food bolus contracts

food bolus is pushed along the gut

The rhythmic contraction and relaxation of the muscles of the gut wall to move food along the alimentary canal

transports fats and glucose

increase surface area for absorption

one cell thickwith blood capillariesand a lacteal

Structure and function of a villus

villus

muscle wall

lacteal

SummaryThe digestive system

• is the system of organs that are involved in the process of digestion

• is made up of the alimentary canal and associated glands

Movement of food along the alimentary canal

• by peristalsis

Absorption of digested food

• by villi