Active transport in humans

• Active transport also happens in humans, for example in taking glucose from the gut from the kidney tubules.
• Active transport is used in the gut when there is a lower concentration of nutrients in the gut but a higher concentration in the blood.
• When there's a higher concentration of glucose and amino acids in the gut they diffuse naturally into the blood, but sometimes there is a lower concentration of nutrients in the gut then there is in the blood which means the concentration gradient is the wrong way so active transport is used.
• Active transport allows nutrients to be taken into the blood, despite the fact that the concentration gradient is the wrong way, this means that glucose can be taken into the bloodstream when its concentration in the blood is already higher than in the gut. It can then be transported to cells where its used for respiration.