: an exaggerated reaction to the male-oriented ''shoot-'em-up games''. noun. A movie or TV program with much gunplay and violence: gambled for cigarettes, slurped Tang or watched shoot-'emups on TV (1953+)
Circulatory system. The human circulatory system (simplified). Red indicates oxygenated blood carried in arteries, blue indicates deoxygenated blood carried in veins. Capillaries, which join the arteries and veins, and the lymphatic vessels are not shown.
Agreed - arterial (oxygenated) blood is bright red and and venous is much darker but still unequivocally red! Even in a vacuum it would still be red because of the red haem pigment, as Neil says. This I understand, but what then causes the optical illusion that makes it *appear* to be blue through the skin.