define, analyze, explain and differentiate the overall functions of the following regions of the digestive system. mention the enzymes involved in the digestion of proteins, fats and carbohydrates to include :

• where they secreted from
• their substrate and product
• the conditions for their reactions.

a). the mouth

b). the oesophagus

c). the stomach

d). the liver and the pancreas (functions only)

e). the small intestine

f). the large intestine

g). the rectum.