The absorption of glucose needs 5 physical things: villi, microvilli, mitochondria, carrier proteins (for facilitated diffusion) and co-transporters (for indirect active transport).
Villi
Adaptation Explanation
-walls of intestine are folded into villi -increase surface area
-the walls are very thin (1 cell thick( -short diffusion pathway
-rich blood supply behind wall -maintains a steep concentration gradient
-the villi's muscles contract and relax -churns the food to ensure glucose rich food replaces old food
-walls of intestine are folded into villi -increase surface area
-the walls are very thin (1 cell thick( -short diffusion pathway
-rich blood supply behind wall -maintains a steep concentration gradient
-the villi's muscles contract and relax -churns the food to ensure glucose rich food replaces old food
Microvilli
Facilitated Diffusion and Glucose Absorption
-glucose is constantly being used up be cells and moved by blood so there is always a higher concentration of glucose in the lumen than in the blood.
-this means that there is a concentration gradient from the lumen into the blood, allowing facilitated diffusion.
-this means that there is a concentration gradient from the lumen into the blood, allowing facilitated diffusion.
Active Transport and Glucose Absorbtion
-even though the net movement of glucose will be into the cell, the diffusion will reach a point of equilibrium and so glucose will be lost in faeces.
-therefore, the epithelial cells have a system involving active transport to absorb the rest of the glucose.
1)
-therefore, the epithelial cells have a system involving active transport to absorb the rest of the glucose.
1)