external and internal organ of heart​ ?

Answer :

Answer:

i don;t understand what you're asking

Explanation:

The heart wall consists of 3 layers:
Epicardium: thin external layer formed by visceral layer of serous pericardium
Myocardium: thick middle layer made of cardiac muscle
Endocardium: thin internal membrane that lines the heart and its valves. It is composed of endothelium and sub-endothelial connective tissue, similar to intimal component of blood vessels.