Small intestine & lactose intolerance

Question 1

How is glucose absorbed in the small intestine?

Answer 1

Through the walls which are highly folded and contain villi which increase the surface area for absorption. The wall of villi is a single layer so short pathway and the villi contain blood capillaries which absorb glucose molecules. The continual blood flow maintains a high gradient for continual absorption.

Question 2

How are the epithelial cells adapted for max absorption?

Answer 2

The microvilli of the epithelial cells increase SA, increasing rate of diffusion.
Carrier and channel proteins on active transport and facilitated diffusion.
Numerous mitochondria which supply ATP for the active transport.

Question 3

What is lactose intolerance?

Answer 3

The inability to produce enough lactase to digest lactose

Question 4

What are the causes of lactose intolerance?

Answer 4

Genetical inheritance or their lactase production is disrupted by disease.

Question 5

What are the symptoms of lactose intolerance?

Answer 5

Undigested lactose can’t be absorbed which lowers the water potential in the lumen below the cells/ blood. Water moves into the lumen by osmosis, causing diarrhoea. Also flatulence, abdominal cramps and bloating.