We used to associate heart and love. I asked my self what is the evidence for that?
we always say " I feel pain in my heart" if we did not see our friends or parents for a long time. why we do not say" I feel pain in my kidneys" for example. My brother is studying in the outside and sometimes my mother says "afnan my heart hurts me" But in fact I see different thing because she looks tired in all her body . So maybe the heart is the main organ in the body which linked with love but in the same time the remain organs also work with heart and affected by feelings. We face a lot of problems in our daily life and the heart can not bear every thing alone so the remain organs come to heart and say" Do not worry we will help you" :)
And this just my opinion and my thinking without scientific reasons of course ...