Why the heart does not absorb the blood directly(for it's oxygen requirement) rather than taking it through coronary circulation? Is it related to the permeability of myocardium? Having such a circulation system can help in avoiding diseases which arise due to issues in coronary circulation.
1 Answer
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Oxygen and nutrients diffuse out of capillaries into surrounding tissue.
If you don't have sufficient density of capillaries, diffusion distances are too long, and tissue becomes anoxic and dead. See for example:
Henquell, L., Odoroff, C. L., & Honig, C. R. (1977). Intercapillary distance and capillary reserve in hypertrophied rat hearts beating in situ. Circulation Research, 41(3), 400-408.
In other words, the heart muscle is far, far too thick, even in a rodent, for enough oxygen to be delivered without vascularization of the myocardium.
answered May 26, 2022 at 13:46