…showed first 75 words of 1403 total…

…showed last 75 words of 1403 total…while the white cells advance more slowly along the walls of the capillaries. The capillaries present a far larger surface with which the blood comes in contact than do other blood vessels end because they consequently offer the greatest resistance to the progress of the blood, they have a great influence on the circulation. Capillaries expand when temperature rises and help to cool the blood then they contract in cold and help preserve internal heat.