But just because you have a gym membership that you actually use doesnât mean you canât also have a few things at home for doing other types of workouts that you donât have time for at the gym, or for those days that you just canât make it out the front door.
The inside wall of the small intestine needs to be thin, with a really big surface area. This allows absorption to happen quickly and efficiently. If the small intestine had a thick wall and a small surface area, a lot of digested food might pass out of the body before it had a chance to be absorbed.
In the digestive system, absorption means the uptake of digested food into the blood.   Diffusion is one way in which food can be absorbed into the blood. If the conc â¦ entration of food is higher in the intestine than it is in the blood, food can diffuse down the concentration gradient into the blood.   If the concentration of food is lower in the digestive system than in the blood then it cannot be absorbed by diffusion.