How do the walls of the atria compare with the walls of the ventricles and why are they different

Explanation:

The width of the muscular wall (myocardium) in the ventricles is greater than the width of the atria due to the force exerted by the heart to initiate major circulation (left ventricle) and minor or pulmonary circulation (right ventricle).

This is because in the human circulatory system, the major / systematic circulation that sends oxygen-rich blood (O2) and nutrients to the organs, starts from the left ventricle and ends in the right atrium, where blood is collected with the debris from cellular respiration. Then it passes through the tricuspid valve to the right ventricle and the minor / pulmonary circulation begins at the moment that the ventricle contracts strongly and expels the blood into the lungs, where the gas exchange in the pulmonary alveoli will occur again oxygenating the blood and being collected by the left atrium that connects to the left ventricle through the bicuspid or mitral valve and the process of major circulation begins again.

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.