2.31: Describe the Structure of a Villus and Explain how this Helps Absorption of the Products of Digestion in the Small Intestine

VILLUS: The Inside of the Small Intestine is lined with villi and are folded to increase the Surface Area to Volume Ratio

• Their function is to Absorb Digested Soluble Molecules into the Circulatory System for Use, Hence why they contain Blood Capillaries to carry the Molecules away for Assimilation through the Hepatic Portal Vein

Diagram:

                                        

ADAPTATIONS:

ADAPTATION	FUNCTION
THIN CELL WALLS	Thin Cell Walls (One Cell Thick) so the Distance of Diffusion of Digested Soluble Molecules is Short, Allowing the Efficient Rate of Diffusion
LARGE SURFACE AREA TO VOLUME RATIO	Villi is Folded to Increase the Surface Area to Volume Ratio so More Molecules can Diffuse into the Villi at Once, Increasing the Rate of Diffusion
STRONG CONCENTRATION GRADIENT PROVIDED BY BLOOD SUPPLY	Contains Blood Capillaries, creating a Strong Concentration Gradient to Allow the Efficient Rate of Diffusion of Molecules Such as Glucose and Amino Acids to be Transported to Assimilating Cells
LACTEAL	Lacteal Transports Fatty Acids and Glycerol Away from the Small Intestine in the Lymph