Salaams,
I have a problem with these kind of posts that claim to prove a new "miracle" of the Qur'an. Did you know, for instance, that our GI system contains 5 million neurons? In fact, it is sometimes called the "second brain," and the term for the network of neurons in the GI system is the "enteric nervous system." (read more here:
https://en.wikipedia.org/wiki/Enteric_nervous_system). It has its own term because it is really unique and has its own independent reflex activity.
Would you like more info about the "second brain?" Here it is:
https://www.scientificamerican.com/a...stems-excerpt/
So putting that into context, the fact that the heart has 40,000 neurons is no big deal. It certainly does not show that the heart is "thinking" because for something to "think", it must have a "mind" of its own and therefore a "consciousness". The heart is by no mean "conscious" or "mindful".