The
Heart of the Matter
Because giraffes
are so tall, their hearts must be capable of pumping blood at a high enough
pressure to flow up through their necks and into their brains. For this reason,
a giraffe’s heart has special adaptations to overcome gravity. A giraffe’s
heart can weight up to 25 pounds, and is several inches thick, making it very
powerful. Additionally, a giraffe’s heart pumps around 16 gallons of blood per
minute!
Giraffe heart
These strong
hearts also produce an average blood pressure of 280/180, which is twice the
pressure of other large mammals, and more than twice the recommended human
blood pressure of 120/80. This high blood pressure is necessary for blood to
reach the brain, but could be dangerous when a giraffe lowers its head. For
this reason, giraffes have a pressure-regulating system made up of small blood
vessels called “rete mirabile,” anti-pooling valves, and reinforced artery
walls. This complex system prevents excessive amounts of blood from rushing
toward a giraffe’s brain when it lowers its head. The jugular veins in giraffes
also have valves that stop blood from flowing backwards into the head when its
lowered.
Interesting fact of the week:
Giraffes have heart rates of around 150-170 beats per minute!
Work's Cited
Bourton, Jody. "Supercharged Heart Pumps Blood Up A Giraffe's Neck." Earth News. BBC, 20 Nov. 2009. Web. 08 Apr. 2012. <http://news.bbc.co.uk/earth/hi/earth_news/newsid_8368000/8368915.stm>.
"Facts About Giraffes." About.com: Animals / Wildlife. Web. 05 Apr. 2012. <http://animals.about.com/od/hoofedmammals/a/tenfactsgiraffes.htm>.
"Giraffes- All You Never Wanted to Know." Squidoo. Web. 08 Apr. 2012. <http://www.squidoo.com/giraffes-all-you-never-wanted-to-know>.
I had no idea the Giraffe's heart was that huge! It is also interesting to see the way they have to bend down because they are so tall (the second picture you posted).
ReplyDeleteWow this is really interesting! Giraffe hearts really are huge! What i thought was most interesting though was how the giraffe body learned to adapt with its height by developing a pressure regulating system. It would be interesting to go back and see how this system evolved as giraffe's as we know them today came to be! Do you know what animals the giraffe is descended from?
ReplyDeleteWow, the heart is so huge but it has to be to pump so much! Do giraffes frequently have heart problems or not?
ReplyDeleteWow!! That's fascinating. Great topic and very interesting fact.. I had no idea how big the hearts of giraffes are. I am working in a Cardiac Care center, and really enjoying learning about the heart, so I really enjoyed reading this blog post. Great blog :)
ReplyDeleteI'm about to make a papier mache giraffe head, life sized - what are the dimensions of a giraffe's head?
ReplyDelete