Venice, a seaport city in Italy, was built on islands in a lagoon, which remains flooded throughout the year.
Boats—not cars—carry people from one part of the city to the other. So, you might be wondering, what does this have to do with blood?
Your circulatory system—blood vessels and heart—is a lot like Venice. The “streets” of Venice are a circular maze of water-filled canals. Those canals are like the watery plasma that flows through your blood vessels. Just as you have major arteries and veins, Venice has a big, central Grand Canal. It branches into smaller and smaller canals, just as your blood vessels branch into smaller and smaller tubes. The canals reach every part of the city, much as your vessels reach every part of your body.
The likeness doesn’t end there. Twenty-four hours a day, blood leaves your heart, circulates through your body, and then returns to your heart. Likewise, boats leave the station at the “heart” of Venice 24 hours a day. They circulate around the canals and then return to the station. Delivery boats act like red blood cells, ferrying food and other needed items all around the city. Garbage boats are more like white blood cells, picking up trash and taking it to the dump.
