Question

Assimilation comes before absorption or after it

Answer 1

Assimilation comes after absorption.

When digestion is complete, the digested food must be moved from the digestive system into the blood system for movement around the body. This process is called ABSORPTION and it occurs in the small intestine. The small intestine is specially adapted for this function.

Molecules can pass from the cavity (lumen) of the small intestine through the epithelium of the villi into the blood capillary network or the lacteals.

Small molecules such as amino acids and monosaccharides enter the blood capillary network and are carried away by the blood.

Larger molecules from fat (lipid) digestion enter the lacteal. The lacteal empties its contents into the lymph system, which eventually empties its contents into the blood system.

The uptake of nutrients into cells and tissues and consequent building up into more complex substances (as opposed to breaking down for the release of energy, which is respiration) is called ASSIMILATION.