Co-transport and absorption in the ileum

Question 1

What is the Ileum

Answer 1

Small intestine

Question 2

Epithelial cells lining the ileum posses microvilli

Answer 2

These are finger-like projections of the cell surface membrane about 0.6 micrometers in length (collective: brush border)

Question 3

Microvilli provide more SA for the insertion of carrier proteins through which diffusion can take place

Answer 3

Another mechanism to increase transport across membranes is to increase the number of protein channels and carrier proteins in any given area of membrane

Question 4

As carbohydrates and proteins are being digested continuously there is normally a greater concentration of glucose and amino acids within the ileum than in the blood

Answer 4

Given that the blood is being continuously circulated by the heart the glucose absorbed into it is continuously being removed by cells as they use it up during respiration which helps maintain the concentration gradient between the inside of the ileum and the blood.

Question 5

Diffusion only results in the concentration either side of the intestinal epithelium becoming equal

Answer 5

This means that not all the available glucose and amino acids can be absorbed this way and some may pass out of the body