Describe the adaptations of the small intestine to help perform it's function

The small intestine is an organ which absorbs the products of digestion (sugars and amino acids etc) into the blood. One of the primary functions of the small intestine is to act as a large surface for absorption and this is achieved by various adaptations. Villi are small finger like projections which line the interior of the small intestine and act to maximise the available surface for absorption of nutrients, micro-villi are microscopic cellular projections located on the surface of the villi and further increase the surface area of the organ allowing for more efficient diffusion into the bloodstream. The size of the organ plays a large role as at 5 meters in length it allows not only for a greater surface area but an increased time for nutrient absorption.Further adaptations such as extremely thin cell membranes reduce the diffusion distance, greatly speeding up the process of absorption. In addition to this a good blood supply carried via a network of capillaries increases the concentration gradient of nutrients by continually refreshing the blood in the villi therefore amplifying diffusion rate.