Which junctional tissue of our heart is known as pacemaker and why?

Cardiac impulses originate from the sino-atrial node (SA node) and are passed on to the bundle of his by the atrio-ventricular node. Thus, the SA node initiates and maintains the rhythmicity of the heart. Hence, it is known as the pacemaker.

What is the AV junction made of?

The AV node is composed of three types of cells: spindle-shaped cells within the compact AV node near its junction with the His bundle; transitional cells having features that are intermediate between atrial myocytes and spindle-shaped cells typical of the compact AV node; and left and right inferior extensions of the …

Do the atria contract in a junctional rhythm?

In the case of a junctional rhythm, the atria will actually still contract before the ventricles; however, this does not happen by the normal pathway of activation and instead is due to a backwards or retrograde conduction (conduction comes from the AV node into and through the atria).

Is the AV junction the heart’s secondary pacemaker?

The heart actually has two natural pacemakers. The sinoatrial node (SA node) is the primary pacemaker and the atrioventricular node (AV node) is the secondary. The AV node is in a bundle of tissues on the border that separates the right atrium and the right ventricle.

What is a junctional heart rhythm?

A junctional rhythm is where the heartbeat originates from the AV node or His bundle, which lies within the tissue at the junction of the atria and the ventricle. Generally, in sinus rhythm, a heartbeat is originated at the SA node.

What are the functions of the AV node?

The AV node controls the passage of the heart’s electrical signal from the atria to the ventricles. After an electrical impulse is generated by the sinus node (located at the top of the right atrium), it spreads across both atria, causing these chambers to beat.

What is AV node and its function?

The atrioventricular node (AVN) is a complex structure that performs a variety of functions in the heart. The AVN is primarily an electrical gatekeeper between the atria and ventricles and introduces a delay between atrial and ventricular excitation, allowing for efficient ventricular filling.

What is junctional rhythm of the heart?

What area of the heart is responsible for junctional rhythms?

1. The AV node (junction) can function as the heart’s pacemaker or it may initiate an isolated escape (late) beat when the sinus node fails to fire on time, or it may trigger early ectopic beats (PJCs). 2. Junctional complexes usually appear due to depression of the SA node.

What causes junctional rhythm?

Junctional rhythm can be due to hypokalemia, MI (usually inferior), cardiac surgery, digitalis toxicity (rare today), sinus node dysfunction, or after ablation for AV node reentrant tachycardia. It can be caused by necessary medications (e.g., β-adrenergic blockers, verapamil, digitalis, sotalol, amiodarone).