P

Why Don't We Have Two Hearts?

11 Answers
We have two kidneys, 2 lungs etc. How come we don't have 2 hearts?
C

The only person that I have read about who had two hearts is George Lippert and he successfully lived for 62 years. So, your question is not unrealistic or an impossible one, but to understand why we were bestowed with one heart ,despite having a pair of several organs , one would need to understand the architecture of our circulatory system that doesn't just carry blood from our heart to various organs of the body , but also exchanges nutrients and oxygen and brings back carbon dioxide and other waste products from the organs during the exchange.

Simplistically , the heart sends the oxygenated blood through the arteries , the principle and the largest artery connected directly to the heart is the aorta. This blood then branches into the arteries. Thus arteries carry the pure ( oxygenated and nutritious ) blood. The exchange of the nutrients and oxygen (to the tissues) and carbon dioxide and other waste products (from the tissues) takes place through the capillaries , permitting the exchange due to their intertwined network and thinness of the wall, connecting the arteries with the veins. Now, after the capillaries get the wastes from the cells , the blood is now passed on to the veins. Thus veins carry the deoxygenated and impure blood that has to go back to the heart. All the veins drain into two principle veins known as the superior and inferior venacava. The superior carries the impure blood from the upper extremities of the body while the inferior venacava carries the blood from the lower part. Once this blood is poured into the heart, the cycle resumes.

Now, if we had two hearts , then we would need to have two principle aortas and four principle venacavas . Thereafter, all the arteries , capillaries and veins would at least need to double in number to distribute the task among to functional hearts. This would mean a tremendous increase in the number of vessels in our circulatory system allowing them less space to dilate or relax when required thus leading to a periodical increase of blood pressure. And as we are aware, an increased blood pressure would be accompanied by several other associative diseases.

So, although a two heart system is realistically feasible , as has been shown in the lifetime of George Lippert, it has the potential to create a system whose overload of resources may become a potential threat to the system and a constant maintenance nightmare.

On a more romantic note perhaps God willed us to have just one sweetheart at a time and hence one heart per person :)

...
R

We may not have two distinct hearts but the chambers of the heart perform two distinct functions.

There are 2 chambers or ventricles on each side of the heart - they work together and are finely synchronised but perform different roles for our bodies and what each of the 4 chambers does affects different parts of our bodies.

If you read this fascinating page : http://www.skillstat.com/heartscape/chambers.htm you will see that the one heart is, at a basic level (what the left and the right side does) two organs - but at a more complicated level does so mush more than one or two organs.

I guess that it is the diversity of the functions of the heart that has dictated it's evolution into "one" organ thus helping it at all the phases and levels that any one of it's many functions must synchronise with it's other functions.

In other, "paired", organs - lungs, kidneys etc each one of the pair does the same function as the other, which is why we can live with one kidney or one lung - but we could not live with only 3 chambers of the heart - we need all 4 working together to survive.

...
P
Tipsmo28 - I think the analogy of a car having two drivers would apply more so to having two brains. In that case there would be confusion with both brains having different goals. In a sense we do have 2 brains. The human brain has a left and right hemisphere with a communication channel in between.
Reporm60 - Ther wouldn't be any advantage in one heart providing blood to the upper body and the other heart supplying the lower body because if one heart failed, part of the body would due to the lack of a blood supply.

If I was "designing" the human body I would have both hearts working in parallel so that if one failed the other heart would have enough capacity to handle the workload. It would be a bit like connecting two batteries or pumps in parallel. The main problem though would be synchronising the two hearts to beat at the same time. The human heart has a pacemaker which sends out an electrical pulse that spreads throughout the heart and causes the muscles to contract. If there were two hearts, they would have to be linked by a nerve so that the pacemakers pulse together.

...
R

Actually God has designed humans in the perfect way possible. To circulate blood throughout the body, there has to be a centralised system, which can monitor all the blood flow. If there were two hearts, then those two hearts would have divided sections amongst themselves like heart one would take the upper body and heart two would take the lower.

What happened if anyone of those hearts failed? Half of your body would not get blood, and you would die anyway. Hence whether there is one heart or two, the failure of anyone would be fatal. Hence it is better to keep only one heart in there, and make some space for two lungs and two kidneys.

...
P

The way I would "plumb" the two hearts would be to merge the two aortas, vena cavae, pulmonary arteries and pulmonary veins from each heart together into single blood vessels so there would still only be one circulatory system. As far as I know if you were doing this with water pumps you would have to put check valves in each pipe before they merge to prevent one pump pumping into the outlet of the other pump due to the difference in pressure. I'm sure though the analogy between mechanical and biological pumps can only be stretched so far.
If there are any mechanical engineer members of Mybestanswer out there, what are your thoughts on this ?

...
C

Hi Points27

Yes, that is a possibility and the analogy with the mechanical pump might work , but then we might have to increase the size and width of the system ( body ) to accommodate an enhanced network of pipes ( vessels ). So yes, if the size of the human body is increased, then thus could probably be possible. For example : the case study of George Lippet that I mentioned was probably viable because he had three legs as opposed to the two, but yes the probability of two functional hearts isn't unimaginable even if exceptional.

...
C

Yes, why don't we have two hearts? When one is broken, another one can still function.

Wait, hold on! Why not we have two each of everything in our bodies; two mouths, two noses, two navels, two sex organs, etc?

Ok, your wish is granted. Now, where are you going to place all these extras on your face and body?

This is just a joke to amuse all of you after a week of hard work.

...
T

Friend,I think it is a philosophy. Just think, a car has two front wheels, two rear wheels, but why only have one driver? we just need one driver to decide where we will go, if we have more than that? What will hapend?

one heart is the perfect creation of the God as the main controller of our all body's systems.

...
P

It all depends on how you look at it.

We can have one heart with two sides

or

We do have two little hearts that fit together. (just looks like one)

:)

...
T

Well we don't have two hearts physically but we do have multiple hearts! one is kind other is rude ,3rd is loving ,4th is worried! .Take care!

...
T

There would be no point to have two hearts since it has one function and that control breathing and blood pumps

...