Conduction System of the Heart

Study Notes

Conduction System of the Heart

Purpose: Coordinates heartbeats, ensuring efficient blood circulation.
Key Components:
1. Sinoatrial (SA) Node:
  - Located in the right atrium.
  - Primary pacemaker of the heart.
  - Initiates electrical impulses (60-100 beats per minute).
2. Atrioventricular (AV) Node:
  - Located between the atria and ventricles.
  - Acts as a gateway, delaying impulses from the atria to the ventricles (allows atria to contract fully before ventricles).
  - Can act as a backup pacemaker (40-60 beats per minute).
3. Bundle of His (Atrioventricular Bundle):
  - Pathway for electrical signals from the AV node to the ventricles.
  - Divides into right and left bundle branches.
4. Purkinje Fibers:
  - Network of fibers that spread throughout the ventricles.
  - Conduct impulses quickly, causing coordinated contraction of the ventricles (20-40 beats per minute if other nodes fail).
Electrical Conduction Pathway:
1. SA Node →
2. Atrial Muscles (contraction) →
3. AV Node (delay) →
4. Bundle of His →
5. Right/Left Bundle Branches →
6. Purkinje Fibers (ventricular contraction).
Autonomic Regulation:
- Sympathetic Nervous System: Increases heart rate and force of contraction.
- Parasympathetic Nervous System: Decreases heart rate.
Clinical Significance:
- Arrhythmias can occur when there is a malfunction in any part of the conduction system.
- EKG (electrocardiogram) is used to assess electrical activity and identify conduction issues.

Purpose of the Conduction System

Coordinates heartbeats to ensure efficient blood circulation.

Key Components

Sinoatrial (SA) Node:
- Located in the right atrium and serves as the primary pacemaker of the heart.
- Initiates electrical impulses at a rate of 60-100 beats per minute.
Atrioventricular (AV) Node:
- Positioned between the atria and ventricles, it functions as a gateway for electrical signals.
- Delays impulses to allow complete atrial contraction before ventricular contraction.
- Can serve as a backup pacemaker with a rate of 40-60 beats per minute.
Bundle of His (Atrioventricular Bundle):
- Transmits electrical signals from the AV node to the ventricles.
- Splits into right and left bundle branches for signal distribution.
Purkinje Fibers:
- A network of fibers that extends throughout the ventricles, facilitating rapid conduction of impulses.
- Ensures coordinated contraction of ventricles, able to maintain a rate of 20-40 beats per minute if higher nodes fail.

Electrical Conduction Pathway

Flow of electrical signals:
- SA Node → Atrial Muscles (causing contraction) → AV Node (introduction of delay) → Bundle of His → Right/Left Bundle Branches → Purkinje Fibers (leading to ventricular contraction).

Autonomic Regulation

Sympathetic Nervous System:
- Increases both heart rate and force of contraction.
Parasympathetic Nervous System:
- Decreases heart rate, maintaining a balance in cardiac function.

Clinical Significance

Malfunctions within the conduction system may lead to arrhythmias, which are irregular heartbeats.
Electrocardiogram (EKG) serves as a diagnostic tool to assess electrical activity and detect conduction abnormalities.

Description

Explore the vital components of the heart's conduction system, which ensures efficient blood circulation by coordinating heartbeats. Learn about the functions of the SA node, AV node, Bundle of His, and Purkinje fibers in this informative quiz.