Hi. Can someone help me with this topic. I am quite confused. How can vasoconstriction increase blood pressure yet decrease blood flow? Cause according to the laws that govern hemodynamics, when you have a small caliber it means you have an increase velocity, increase pressure, increase flow, increase resistance (e.g. in capillaries). And when you have a large caliber, less velocity, less pressure, less blood flow, less resistance like that of the aorta. however when you took the example of blushing which is due to vasodilation, the mechanism explains that because of the dilation of the blood vessels there is decrease resistance, hence more blood flow. *Doesn't this defy the Poiseuille law?