Final answer:
The term for the polarization of cardiac muscle fiber is depolarization, which is the process causing the heart muscle to contract, followed by repolarization to prepare for the next contraction. An ECG measures these phases to assess heart function.
Step-by-step explanation:
The term used to describe the polarization of the cardiac muscle fiber is depolarization. When depolarization occurs in the heart muscle, it causes the muscle to contract. This process is essential for the heart's function as it allows the coordinated rhythmic contractions that propel blood through the circulatory system. After the heart muscle contracts, it then undergoes repolarization, which resets the muscle fibers and prepares them for the next heartbeat.
An Electrocardiogram (ECG) measures these electrical phenomena, specifically the components of depolarization and repolarization within the heart muscle, providing significant insights into the heart’s functioning. A wave of depolarization spreads across the heart starting from the sinoatrial (SA) node, causing subsequent areas of the heart to undergo depolarization and contract in a well-organized manner. This cycle of contraction (depolarization) and relaxation (repolarization) is a repeating process that constitutes the heartbeat.