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.
Absorption primarily takes place in the small intestine, specifically in the lining of the small intestine where nutrients are absorbed into the bloodstream. The small intestine is well-suited for absorption due to its large surface area created by villi and microvilli.
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.
It is long enough to provide sufficient time for absorption. It's surface area is also increased as its inner walls have many folds and have many small finger-like projections called villi and the epithelial cells of villi have many microvillis. thirfly, the villi have walls or membranes that are only one-cell think and lastly. the villi are richly supplied with blood cappilaries and lymphatic vessels (lacteals that carry away absorbed nutrients like fats . each lacteal in each villus is also surrounded by blood capillaries that transport glucose and amino acids away from the small intestine.
Yes, capillaries are nearly everywhere in your body.
Pulmonary Capillaries
capillaries
about 7000 are in it and if you don't think is right than look some were else!
These "hair-like things" are called villi, and it is their job to absorb nutrients into the capillaries. They are tiny, and each single villus has dozens of microvilli, hugely increasing surface area. Combined with a mere 50 micrometre thick distance for substances to difffuse across, as well as a constantly steep concentration gradient thanks to a fast-flowing capillary network, molecular absorption into the bloodstream is maximised.
Glomerulus
Each alveolar sac is surrounded by a network of capillaries that facilitate the exchange of gases (oxygen and carbon dioxide) between the air in the sac and the bloodstream. This close proximity allows for efficient gas exchange in the lungs.
Bowman's Capsule