What are the adaptations of the small intestine?

Answer 1

In this case, I am assuming that you are asking for the diffusion of digested food substances, namely fats, sugars (glucose)and amino acids. Firstly, the surface area of the small intestine is increased: 1. the inner walls of the small intestines have numerous folds 2. the inner walls of the small intestine are also lined up with numerous minute finger-like projections called villi. These villi further increase the surface area for absorption. 3. The epithelial cells of the villi, in turn, have numerous microvilli to further increase the surface area Secondly, the small intestine is super long, about seven metres in an adult. This provides sufficient time for the absorption of digested food substances. Thirdly, the aforementioned villi have thin walls or membranes (epithelium is only one cell thick) Fourthly, the intestinal wall and the villi have many capillaries to carry away the absorbed food substances. In each villus is a lacteal or lymphatic capillary surrounded by blood capillaries. The lymphatic capillaries of the villi transport fats while the blood capillaries transport amino acids and sugars away from the intestine. Glucose and amino acids are thus absorbed by diffusion into the blood capillaries of the villi. Do note that the rate of diffusion is affected by the speed of blood flow. Slower blood flow will impair diffusion due to gentler concentration gradient. Hope this helps. The information provided is from a Biology Textbook published from Marshall Cavendish Education, Singapore.

Answer 2

In this case, I am assuming that you are asking for the diffusion of digested food substances, namely fats, sugars (glucose)and amino acids. Firstly, the surface area of the small intestine is increased: 1. the inner walls of the small intestines have numerous folds 2. the inner walls of the small intestine are also lined up with numerous minute finger-like projections called villi. These villi further increase the surface area for absorption. 3. The epithelial cells of the villi, in turn, have numerous microvilli to further increase the surface area Secondly, the small intestine is super long, about seven metres in an adult. This provides sufficient time for the absorption of digested food substances. Thirdly, the aforementioned villi have thin walls or membranes (epithelium is only one cell thick) Fourthly, the intestinal wall and the villi have many capillaries to carry away the absorbed food substances. In each villus is a lacteal or lymphatic capillary surrounded by blood capillaries. The lymphatic capillaries of the villi transport fats while the blood capillaries transport amino acids and sugars away from the intestine. Glucose and amino acids are thus absorbed by diffusion into the blood capillaries of the villi. Do note that the rate of diffusion is affected by the speed of blood flow. Slower blood flow will impair diffusion due to gentler concentration gradient. Hope this helps. The information provided is from a Biology Textbook published from Marshall Cavendish Education, Singapore.