Thursday, December 3, 2015

Giraffe - All Heart

It's probably more like 'all tongue' although it's a lot about 'all heart,' too. The tallest land mammal on the planet, the giraffe's heart must have special mechanisms to enable it to pump blood up the animal's long neck—with 7 elongated vertebrae—to its head. It’s a formidable task to pump blood at a pressure high enough to flow up the giraffe's neck to their brain. To accomplish this, a giraffe's heart can weigh up to 10 kg or 22 pounds and generate twice the blood pressure of other large mammals. Having enough blood pressure to pump blood to the brain when the giraffe's neck is extended upward is one challenge. Another challenge occurs when a giraffe lowers its head, which could create grave risks due to excessive blood pressure. To counter this, according to the National Geographic, giraffes possess a rete mirabile, so called. It is a pressure-regulating system that restricts the amount of blood that rushes towards the brain when the giraffe lowers its head. I also was able to feed a 14-month old giraffe that was already taller than the platform on which I was standing.

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