or is it a misconception?
2006-08-10 02:38:32 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Zoology
I am afraid you must have gotten that wrong. Indeed, as many here pointed out already, whales, like all other mammals, have a four chambered heart. It is of course quite substantially bigger than the heart of a human, but it is basically build the same way. The reason that mammals have a four chambered heart is that it allows them to provide their body sufficiently with oxygenated blood and nutrients. In hearts with fewer chambers, blood pressure will drop of significantly after the blood has been pumped to the site of gas exchange. for example in teleost fishes, blood pressure is quite low by the time blood leaves the gills loaded with oxygen. Consequently, these animals have a circulatory system that is less efficient and equips them less well for long lasting activities. In addition, in hearts with two or even one chamber only, oxygen rich and oxygen poor blood is mixed. Not very good from an efficiency perspective.
In the four chambered heart, the oxygen poor blood that comes from the body enters the right atrium, from where it is shuttled into the right ventricle. The advantage of this two chambered approach is that you can pretty much assure a very constant and effcient flow of blood. From the right ventricle, blood is pumped into the lungs, where CO2 is exchanged for O2. The now oxygen rich blood does not have to travel through the entire body and deliver its oxygen, but rather only a very short distance to the left atrium of the left part of the heart. From there it moves on to left ventricle, which is bigger and has a stronger muscle layer than the right ventricle. From there the blood is pumped into the periphery of the body and can now with great force be transported to the organs where it is needed.
I am going into detail into this for good reason. Whales, like other mammals, are endotherm, that means, they have a more or less consistant body temperature that results primarily from their metabolism. To maintain this temperature, their metabolism needs to be very effective (and they are equipped with lots of blubber, or body fat, to insulate them). Now, as I said above, the bigger the metabolic requirements, the more complex the circulatory system (i.e., four chambered heart vs. two chambered heart). And whales, having quite tremendous metabolic requirement, therefore also have a complex circulatory system with a four-chambered heart.
Perhaps, your misunderstanding has to do with the retia mirabilia of whales. These are very complex blood storage systems the animals use to assure longer diving times and deeper diving depths. As you know, one problem of diving is that you need oxygen, but you can't really efficiently breath water. Well, the same holds of course true for whales. Some whales, as you probably know, can reach great depths. At these depths the ambient pressure compresses their lungs to such a degree that it is next to impossible for gas exchange to take place in them. Consequently, whales have evolved ways of enriching their blood with oxygen at the surface. A rete mirabilis is a structure of numerous blood vessels, all branching off numerous times so that you basically have something lika a big sponge containing oxygen rich blood. From here blood is then transported into the organs that rquire oxygen during lengthy dives. Since there is more than one rete in a whale, I wonder if you eprhaps mistook that for "hearts". But that's just a guess...
Hope this helps.
2006-08-10 17:08:58 · answer #1 · answered by oputz 4 · 0⤊ 0⤋
NO. Mammals have chambers in their hearts to send blood to their lungs and to the rest of their body. That is the number you might be thinking of. You have four chambers. A whale probably does also.
2006-08-10 09:46:46 · answer #2 · answered by Rich Z 7 · 0⤊ 0⤋
One heart... just a really big one! The blue whales heart is the size of a small car!
2006-08-10 10:03:29 · answer #3 · answered by MadMaxx 5 · 0⤊ 1⤋
it's a misconception, although the stegosaurus had two brains, one in the bum area to control the spines and lower body, and the one it the head for yknow, normal stuff
2006-08-10 14:21:27 · answer #4 · answered by bar 3 · 0⤊ 0⤋
Whales have one heart with five chambers.
2006-08-10 17:01:40 · answer #5 · answered by Anonymous · 0⤊ 1⤋
all mammals have a single, four-chambered heart.
2006-08-11 00:26:45 · answer #6 · answered by bad guppy 5 · 0⤊ 0⤋
YES!! n they have 5 HEARTATTACKS everyday!! HAHAHAHA
2006-08-10 09:49:30 · answer #7 · answered by Anonymous · 0⤊ 0⤋
o poor girl who made such a fool out of u!!!!!!!!!!
2006-08-11 02:18:25 · answer #8 · answered by lucifer 1 · 0⤊ 1⤋