: 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.
Human blood is red because of the iron in the haemoglobin. This gives red blood cells their red colour. Veinous blood is much darker than arterial blood, and your teacher is right that oxygenated (arterial) blood is 'redder' than deoxygenated (veinous) blood. However, human blood is not blue. Some animals do have blue blood though.