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.
The diameter of the aorta gradually decreases as blood flow is directed to tissue and organs, flowing through arteries then the smaller arterioles then the capillary beds at the target organ, tissue, etc. Here the oxygen is liberated to the tissue and the blood picks up the resulting CO2. just now. Report Abuse. Oxygenated blood flows from the lungs to the left atrium contractions (heart muscle) cause the blood to leave the atrium and enter the left ventricle. Further contraction causes the blood to leave the atrium and enter the aorta.