STREAMLINE FLOW IN THE ARTERIES OF THE DOG AND CAT

Abstract

Blood flow in the aorta and femoral artery of the cat and the femoral artery of the dog was studied by inserting a short glass tube into the arteries and observing the flow pattern of injected India ink. The streamlined nature of the flow was evident when the ink was injected either into the left ventricle or into the aorta. Blood flow of a streamlined nature was also observed in the femoral vein and inferior vena cava of the cat. Mathematical analysis shows that the kinetic energy term in streamlined flow is twice that in ideal flow. The formulae for the work of the heart and the kinetic energy of blood flow wherever the flow is streamlined have been accordingly modified. Thus the usual approximate formula for the work of the heart should be written: Work of the left ventricle = PV + mI2, where P is the mean aortic pressure, V is the stroke vol., m is the mass of blood ejected (equal to density of fluid times V), and I is the mean velocity (equal to the rate of vol. flow divided by the cross-sectional area of the aortic orifice). Similarly, the kinetic energy is written mI2 wherever the flow is streamlined.