Quote Originally Posted by darkmetal505
Also, tissue repair doesn't work like that in the first place if you are trying to draw parallels to real life. Tsunade said it cut off the chakra channels to each cell. Assuming the system works like blood capillaries, you can't just "rebuild" them quickly if they are destroyed. Repeated use of the jutsu compounds the damage further.
Capillaries are built easily enough by the body. They are everywhere. That's why you bleed, no matter where you happen to cut yourself. If they couldn't be repaired, nothing in the body could be repaired, because all living cells need oxygen, removal of CO2, nutrients and energy, and occasionally the defense mechanisms carried by the blood. Unfortunately even cancer knows how to attract blood vessels.

In any case blood vessels are lined by cells (they must be large enough to let cells pass through after all), so these chakra tunnels are much much smaller, likely mainly built of protein components like any cell surface channels.

But anyway, that's beside the point. My point is how stupid it is Naruto's progress is halted by whatever excuses while none of the enemies ever seem to have such problems, no matter how powerful they are or get. Unless Itachi was really losing his sight, making him the sole exception in addition to Naruto.