Aspartame is the most controversial food additive in history, and its approval for use in food was the most contested in FDA history. In the end, the artificial sweetener was approved, not on scientific grounds, but rather because of strong political and financial pressure.
The arterioles then divide further into capillaries. Capillaries are the smallest blood vessels and their walls are only one cell thick which allows diffusion between the blood and cells to occur. Nutrients and oxygen from the blood diffuses through the capillary walls into the tissues that need it. This is aided by the relatively high blood pressure that also squeezes the oxygen and nutrients through the capillary wall and into the cells of the tissue.
Oxygen travels into the smallest air sacs of the lungs, called alveoli. Capillaries around these air sacs allow blood to exchange oxygen for unwanted carbon dioxide.The oxyge â¦ n-rich blood then returns to the heart to be pumped to the rest of the body. The carbon dioxide in the lungs is passed out of the body through the mouth and nose when we exhale.apillaries around these air sacs allow blood to exchange oxygen for unwanted carbon dioxide. The oxyge â¦ n-rich blood then returns to the heart to be pumped to the rest of the body. The carbon dioxide in the lungs is passed out of the body through the mouth and nose when we exhale.