PATHOLOGY

Detailed explanation-1: -Octopuses have blue blood, three hearts and a doughnut-shaped brain. But these aren’t even the most unusual things about them! Known for their otherworldly look and remarkable intelligence, octopuses continue to reveal astonishing qualities, abilities and behaviour.

Detailed explanation-2: -Did anyone know that some animals have blue blood, especially when it is exposed to oxygen? Can you guess what animals might have blue blood? Lobsters, crabs, pillbugs, shrimp, octopus, crayfish, scallops, barnacles, snails, small worms (except earthworms), clams, squid, slugs, mussels, horseshoe crabs, most spiders.

Detailed explanation-3: -Squid blood is blue, not red as in humans. This is because squid blood contains a copper-containing compound called haemocyanin. In humans, the blood is red and contains the iron compound haemoglobin.

Detailed explanation-4: -As blood leaves the heart and is oxygen-rich, it is bright red. When the blood returns to the heart, it has less oxygen. It is still red but will be darker. This darker red appears blue because of how light travels through the skin.