The intestinal wall contains many folds on which are countless finger-like projections called villi. Villi increase the surface area available for absorption of digested food.
A villus is lined with specialised epithelial cells which on their surface have projections called microvilli again to increase the surface area for absorption.
Fat (yellow) passes through the cell membrane and is collected in the lacteal while glucose and amino acids (green) pass into the capillaries to be transported around the body via the liver.
The lacteal returns fat to the blood via the lymph system.
After its 7 m long journey through the small intestine of an adult food finally moves into the large intestine. Here recovery of water and salt (sodium, chloride) from undigested food matter takes place. The large intestine is also the site of microbial fermentation. Bacteria in the large intestine are responsible for the breakdown of some undigested food (roughage) and the production of vitamins such as vitamin K and the B group vitamins.
Which one of the following increases the rate at which nutrients are absorbed?
Which one of the following would increase the rate at which food is digested?
Proteases are secreted
into the
by the
to breakdown
Food moves along the digestive tract through a process called
Chemical breakdown of food starts in the
Fats start to be chemically digested in the
Microvilli are structures that
Digestion of carbohydrates, such as starch, commences in the
The role of the large intestine is to
Bile is produced by the liver and stored in the gall bladder. It is released into the duodenum and serves to
