10U4 The Ileum

What is the name of the last part of the small intestine?

• Ileum

• Duodenum

• Colon

• Alimentary canal

What is the function of the ileum?

• Absorption of digested nutrients

• Absorption of vitamins and minerals

• Digestion

• Absorption of water

What is the name of the finger-like projections that increase the surface area of the ileum?

• Villi

• Microvilli

• Cilia

• Alveoli

What is the name of the structure inside a villus that is responsible for the transport of fatty acids to the lymphatic system?

• Lacteal

• Villi

• Cilia

• Capillary

What is the function of lacteals?

• Transport fatty acids to the lymphatic system

• Transport glucose to the liver

• Transport carbon dioxide to the lungs

• Transport oxygen to tissues

Why does a villus need a lacteal?

• Because fatty acids cannot be carried in the blood

• To increase the surface area

• To decrease the diffusion distance

• To maintain a concentration gradient

Which of the following adaptations maintains a concentration gradient of nutrients between the ileum and the blood stream?

• Good blood supply

• Villi

• Thin walls

• Lacteals

How does having thin walls help to maximise the rate of diffusion into the blood stream?

• It reduces the diffusion distance

• It increases the surface area

• It maintains a concentration gradient between the ileum and the blood

• It allows for absorption of fatty acids, which are not water soluble

What is the benefit of the ileum having a good blood supply?

• Absorbed materials are quickly carried away, so there is always a higher concentration in the ileum than in the blood.

• It increases the surface area, so there are more opportunities for digested nutrients to pass from the ileum to the blood.

• It allows for the absorption of fatty acids, which are not water soluble and cannot be transported in the blood.

• It reduces the distance that digested nutrients have to travel to get from the ileum to the blood stream.

Giardiasis is a disease caused by a microscopic parasite, which causes damage to villi. What effect would giardiasis have on the absorption of nutrients in the ileum?

• Absorption would be reduced due to reduced surface area of the ileum

• Absorption would be reduced due to increased diffusion distance between the ileum and the blood stream

• Absorption would be reduced due to reduced concentration gradient between the ileum and the blood stream

• Absorption would be increased as the remaining villi would have a better blood supply