Digestion and absorption

Learning objectives

Describe physical digestion as breaking food into smaller pieces without chemical change, increasing the surface area for chemical digestion, and describe its role in the mouth (chewing) and stomach (churning)

Identify incisors, canines, premolars and molars, describe their functions in physical digestion, and describe the structure of a tooth (enamel, dentine, pulp, nerves and blood vessels, cement and gums)

Describe chemical digestion as the breakdown of large insoluble molecules into small soluble molecules, state where amylase, protease and lipase are secreted and act and the products each makes, and state the functions of hydrochloric acid in gastric juice

Describe the digestion of starch by amylase in the mouth and duodenum and by maltase on the wall of the small intestine, and of protein by pepsin in the stomach and trypsin in the small intestine (Extended)

Outline the role of bile in emulsifying fats and oils to increase their surface area, and explain that alkaline bile neutralises the acidic mixture arriving from the stomach to give a suitable pH for enzymes in the small intestine (Extended)

State that nutrients are absorbed in the small intestine and that most water is absorbed there but some in the colon, and at Extended explain how villi and microvilli increase the internal surface area and describe the structure of a villus and the roles of its capillaries and lacteal