Intrinsic Conduction System Flashcards

Study Notes

Intrinsic Conduction System

Comprises auto-rhythmic cardiac cells that regulate the heart's rhythm through impulses (action potentials).
Responsible for initiating and distributing electrical signals across the heart.

SA Node

Located in the right atrial wall near the superior vena cava entrance.
Functions as the primary pacemaker, generating approximately 75 impulses per minute.

Internodal Pathway

Conducts impulses from the SA node to the AV node.
Ensures timely transmission of electrical signals.

AV Node

Found in the inferior part of the interatrial septum, above the tricuspid valve.
Briefly delays each impulse, allowing the atria to contract before the ventricles.

AV Bundle (Bundle of His)

Located in the inferior interatrial septum; singular electrical connection between atria and ventricles.
Critical for the coordinated contraction of the heart chambers.

Bundle Branches

Two branches that extend from the AV bundle, running down the interventricular septum.
Transmit impulses to the ventricles efficiently.

Purkinje Fibers

Fibers that extend through the interventricular septum and into the heart apex, then branch into ventricular walls.
Conduct impulses rapidly throughout the ventricles, facilitating synchronized contraction.

Pathway of Depolarization

Sequence: SA node → Internodal pathway → AV node → Bundle branches → Purkinje fibers.
Electrical events (action potentials) lead to mechanical events (contraction) resulting in a heartbeat.

Normal ECG Wave Tracing

Comprises three main components: P wave, QRS complex, and T wave.

P Wave

Represents atrial depolarization; occurs as the depolarization wave moves from the SA node through the atria.
Duration is approximately 0.08 seconds, followed by atrial contraction.

QRS Complex

Reflects ventricular depolarization; atrial repolarization occurs simultaneously.
Lasts about 0.08 seconds and directly precedes ventricular contraction.

T Wave

Indicates ventricular repolarization; occurs after ventricular contraction.
Duration is approximately 0.16 seconds, leading to ventricular relaxation.

Hidden Atrial Depolarization

Atrial depolarization is masked within the QRS complex, followed by atrial relaxation.

Left Bundle Branch Block

Impulse conduction is delayed in the left ventricle, causing prolonged QRS complex.
Result of slower cell-to-cell transmission compared to the bundle branches and Purkinje fibers.

Tachycardia

Defined as an abnormally fast heart rate exceeding 100 beats per minute.
Causes may include high body temperature, stress, medications, or heart disease.

Description

Explore the fundamental concepts of the intrinsic conduction system of the heart with this interactive flashcard quiz. Learn about key components such as the SA node and how they contribute to the heart's rhythm. Perfect for students studying cardiac physiology.