The coronary sinus in the heart is situated along its

$SAN$ generates an action potential which stimulates both the $A$ to undergo a simultaneous contraction called $B$. This increases the flow of the blood into the ventricles by about $C$ percentage. Choose the correct option for $A, B$ and $C$.

The $Bundle$ $of$ $His$ are:

Chordae tendinae in the heart are found in

Heart beats are controlled by a nodal tissue which is composed of

Provide the definition/explanation for the following heart valves:
$(1)$ $AV$ valve (Tricuspid)
$(2)$ Mitral (Bicuspid) valve