Question

Given what you know about the molecular "micromechanics" of muscle cell contraction, comment on how this atrial contraction might facilitate the subsequent contraction of the ventricle. Try to consider both the passive effects (e.g. natural cell elasticity) as well as cellular and molecular level mechanisms involved in generating contractile force when answering this question.

Answer 1

The two main property of muscular heart is contractibilty and elasticity. The elasticity of heart aids in the opening of heart and contractibility helps in relaxing of heart..

Heart contraction initiate with auricles contraction that lead to the entry of blood into respective ventricles. During auricle contraction, specific veins present in the auricles prevent the flow of blood in backward direction. With the end of contraction of articles , the ventricles start to contract.  

In this way the heart is contracted and relaxed in a regular manner. Thus both contraction and relaxation is important because it give the enough time to relax the heart.