Chapter 12, Problem 33RA

Summary Introduction

To review:

The effect of increased concentration of Ca2+ in the extracellular fluid on heartbeat, and the reason for lowering of blood Ca2+ concentration, which causes muscle spasms.

Introduction:

The cardiac muscles are present only in the heart and the cells of the cardiac muscles are called myocardial cells. These cells are short, striated, branched and are interconnected by gap junctions or electrical synapse. The cardiac cells generate action potential automatically by a pacemaker and it is conducted throughout the length of the cardiac muscle which results in muscle contraction.