Question

Why capillaries are thin walled? why the walls of ventricles are thicker than auricles'?

Answer 1

The walls of ventricles are thicker than auricles because ventricles have to pump the blood to all the parts of the body during their constraction the contract the backward pressure exerted by the blood the walls of the ventricles have to be thicker otherwise it may lead to brusting of heart

Answer 2

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The walls of capillaries are thin because they connect Arteries from veins and thus posses less pressure.

The walls of ventricles are thicker than that of auricles because ventricles possess high pressure while pumping the blood and thus to withstand that much pressure ventricles have thick walls.