The portion of the intrinsic conduction system located in the superior interventricular septum is the:
a. AV node
b. SA node
c. AV bundle
d. Subendocardial conducting network

Verified step by step guidance

1. Step 1: Understand the intrinsic conduction system of the heart, which includes specialized cardiac muscle cells responsible for initiating and propagating electrical impulses that coordinate heartbeats.
2. Step 2: Identify the location and function of each component listed: the SA node (sinoatrial node) is located in the right atrium and acts as the primary pacemaker; the AV node (atrioventricular node) is located at the junction between atria and ventricles; the AV bundle (also called bundle of His) is located in the superior part of the interventricular septum and transmits impulses from the AV node to the ventricles; the subendocardial conducting network (Purkinje fibers) spreads impulses throughout the ventricles.
3. Step 3: Focus on the phrase 'located in the superior interventricular septum' to match it with the correct part of the conduction system.
4. Step 4: Recall that the AV bundle (bundle of His) is the only part of the intrinsic conduction system situated in the superior interventricular septum, transmitting impulses from the AV node to the bundle branches.
5. Step 5: Conclude that the correct answer corresponds to the AV bundle based on its anatomical location and function.

Key Concepts

Intrinsic Conduction System of the Heart

The intrinsic conduction system is a network of specialized cardiac muscle cells responsible for initiating and propagating electrical impulses that coordinate heartbeats. It ensures the heart contracts in a synchronized manner, maintaining effective blood circulation.

Anatomy and Location of the AV Bundle (Bundle of His)

The AV bundle, also known as the Bundle of His, is a part of the conduction system located in the superior interventricular septum. It transmits impulses from the atrioventricular (AV) node to the bundle branches, facilitating coordinated ventricular contraction.

Functions of Other Conduction System Components

The SA node initiates the heartbeat and is located in the right atrium; the AV node delays impulses to allow atrial contraction; the subendocardial conducting network (Purkinje fibers) spreads impulses through the ventricles. Understanding their roles helps differentiate their locations.