19. The lymphatic system is composed of all of the following except A) lymphatic vessels. B) lymph nodes C) the spleen. D) the vena cavae E) lymph. 20. The lymphocytes are most important in A) helping maintain normal blood volume. B) transporting gases to and away from lymph nodes. C) eliminating variations in the composition of interstitial fluid D) transporting lipids from the digestive tract. E) fighting infection. 21. Compared to blood capillaries, lymph capillaries exhibit all of the following except that they A) have no basement membrane. B) are larger in diameter. C) have walls of endothelial cells that overlap like shingles. D) are smaller in diameter. E) are frequently irregular in shape. 22. Lymphatic vessels are located in almost all portions of the body except the A) CNS. B) periphery. C) renal arteries. D) groin. E) throat. 23. Most of the lymph returns to the venous circulation by way of the A) right lymphatic duct. B) thoracic duct. C) cisterna chyli. D) hepatic portal vein. E) dural sinus.