BIOL 2160 Study Guide - Pulmonary Circulation, Pressure Gradient, Hemorheology
Document Summary
Flow rule: circulatory system = closed system. Flow occurs from high pressure to low pressure. Pressure gradients drive flow from high pressure to low pressure. Flow due to pressure gradients = bulk flow: heart creates pressure gradient for bulk flow of blood, a gradient must exist throughout circulatory system to maintain blood flow. Pressure in aorta = mean arterial pressure (map) = 90 mmhg (highest pressure) Pressure in vena cava = central venous pressure (cvp) = 0 mmhg (lowest pressure) Pressures and pressure drops in the pulmonary and systemic circuits (fig. Pressure gradient in systemic circuit much greater than the pulmonary circuit. Flow = d p/r: resistance through pulmonary circuit much less than through systemic circuit. Factors affecting resistance to flow: radius of vessel, length of vessel, viscosity of fluid = h (thickness) o. In arterioles (and small arteries) - can regulate radius: blood viscosity dependent on amount of rbc"s and proteins.
