Question

Physics-A&P Assigment-2019(1) Q Search in Docume Layout References Mailings Review View The radius of the aorta is 1.2 cm, and the radius of a large arteriole is 0.002 cm. (14 points) Calculate the ratio of resistance to blood flow R(arteriole) /R(aorta). Write your answer in scientific notation (nx10"). (8 points) a. b. Which vessel has a greater resistance to blood flow, aorta or arteriole? (2 points) times c. The resistance to blood flow in the arteriole is (greater/lesser) than that in the aorta. Write your answer in scientific notation. (4 points)

Answer 1

The blood flow in vascular system is given as: Blood flow = pi(delta P) r^4/8 eta lambda delta P = difference in pressure r = radius of the vessel eta = viscosity of the blood lambda = length of the blood vessel Blood flow = delta P/Resistance (to blood flow) Resistance = delta P/Blood flow = delta P/(delta P)pi r^4/8 eta lambda Resistance = 1/pi r^4/8 eta lambda = 8 eta lambda/pi r^4 vessel length & viscosity changes very slowly in the body a) Hence R = Resistance to blood flow proportionalto 1/r^4 R(arteriole)/R(aorta) = [r(aorta)]^4/[r(arteriole)] = 1.2^4/0.002^4 = (1.2/0.002)^4 = 600^4 = 1296 times 10^8 = 1.296 times 10^11 b) Hence R(arteriole) = (1.296 times 10^11)R(aorta) so R(arteriole) > R(aorta) c) The resistance to blood flow in arteriole is 1.296 times 10^11 times greater than that in the aorta