Pillbugs, also known as sowbugs, or woodlice, are familiar backyard creepy crawlies to most of us. Pillbugs are correctly. classified as terrestrial Isopods, and belong to the Class Crustacea. Familiar crustaceans include lobsters, crabs, shrimp, and daphnia (water fleas). The crustaceans, in turn, are part of a larger group, Arthropoda, or jointed-legged animals.
Video: Heart and circulatory system. Your heart is a pump. It's a muscular organ about the size of your fist and located slightly left of center in your chest. Your heart is divided into the right and the left side. The division protects oxygen-rich blood from mixing with oxygen-poor blood. Together, your heart and blood vessels comprise your cardiovascular system, which circulates blood and oxygen around your body. Your heart pumps about 5 quarts of blood every minute.
Syringomyelia is a rare disorder in which a cyst forms within your spinal cord. As this fluid-filled cyst, or syrinx, expands and lengthens over time, it compresses and damages part of your spinal cord from its center outward.