Question

26. The velocity of blood flow is in direct proportion to the total cross-sectional area of the blood vessels b, slower in the arteries than in capillaries because arteries relatively large diameter slower in the veins than in the capillaries because veins diameter slowest in the capillaries b c. have a large d. ecause the total cross-sectional area is the 27. Which of these is NOT a function of lymph nodes a. house B-lymphocytes b. filter lymph d. produce lymphocytes produce red blood cells Which of the following would not result in the dilation of the fecdern arterioles and opening of the precapillary sphincters in systemic cap a. a decrease in local tissue O2 content 28. heds? an increase in local tissue CO2 a local increase in histamine a local increase in pH Cancer cells and virus-infected body cells can be killed before activation of adaptive immunity by 29. natural killer cells b.T lymphocytes B lymphocytes d, pinocytosis To assist with lymph return, a. lymph vessels possess mini-pumps that drive lymph forward b. lymph vessels possess valves, like veins, to prevent backflow. c. lymph vessels rely on pressure generated by the heart. d. lymph vessels rely exclusively on the pull of gravity e. lymph-vessels rely o 30. nerated by their muscular walls. mora than one at hhe above is cerec

Answer 1

26. d) slowest in the capillaries because the total cross section area is greatest.( which allows time for exchange of gases and nutrients).

27. c) produce red blood cells (in humans, bone marrow produces red blood cells)

28. d) local increase in pH. ( when there is low pH a lot of acid is present and the precapillary sphincter open)

29) a) natural killer cells (they do not kill by phagocytosis but by apoptosis )

30. e) more than one of the above is correct.( lymph is transported through lymphatic vessels with the help of skeletal muscle pump, and like veins they have valves to prevent back flow) so a) and b) are correct.