Resistance in cardiovascular and pulmonary question

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Does anyone know why in the arteries, the greatest resistance comes from the arterioles [the small diameter vessels] , while in the pulmonary system, the greatest resistance is at the large diameters [trachae, large bronchioles, etc]?

The greatest resistance is at the medium sized bronchi in the airways. The resistance of any individual airway increases as diameter decreases but the overall resistance of the smaller airways is lower because of their parallel arrangement. Both the cardiovascular system resistance and the respiratory system resistance are governed by the exact same equation (Poiseuille's law) so there really isn't that much of a difference.
 
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