Discuss the four unique characteristics of the myocardial cells

Discuss the four unique characteristics of the myocardial cells and the conduction system: automaticity, rhythmicity, conductivity, and contractility.

Discuss the four unique characteristics of the myocardial cells

Characteristics of the myocardial cells
Discuss the four unique characteristics of the myocardial cells and the conduction system: automaticity, rhythmicity, conductivity, and contractility.

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 Defines equilibrium potential and knows its normal value for potassium and sodium ions.

 States how membrane potential reflects a membrane’s relative permeability to various ions.

 Defines resting potential and action potential.

 Describes the characteristics of “fast” and “slow” response action potentials.

 Identifies the refractory periods of the cardiac cell electrical cycle.

 Defines threshold potential and describes the interaction between ion channel conditions and membrane potential during the depolarization phase of the action potential.

 Defines pacemaker potential and describes the basis for rhythmic electrical activity of cardiac cells.

 Lists the phases of the cardiac cell electrical cycle and states the membrane’s permeability alterations responsible for each phase.

 Names the important ion channels involved in the permeability alterations during the various phases of the cardiac cycle.

The student knows the normal process of cardiac electrical excitation:

 Describes gap junctions and their role in cardiac excitation.

 Describes the normal pathway of action potential conduction through the heart.

 Indicates the timing at which various areas of the heart are electrically excited and identifies the characteristic action potential shapes and conduction velocities in each major part of the conduction system.

 States the relationship between electrical events of cardiac excitation and the P, QRS, and T waves, the PR and QT intervals, and the ST segment of the electrocardiogram.

The student understands the factors that control the heart rate and action potential conduction in the heart:

 States how diastolic potentials of pacemaker cells can be altered to produce changes in the heart rate.

 Describes how cardiac sympathetic and parasympathetic nerves alter the heart rate and conduction of cardiac action potentials.

 Defines the terms chronotropic and dromotropic.