The intrinsic ability of cardiac muscle to generate action potentials rhythmically is achieved by the normal pace maker ,the sino atrial node. The sino atrial node is a part of the special excitory and conductive system of cardiac muscle. With the help of a diagram describe this conductive system and how the action potentials spreads throughout the muscle
Unfortunately, as a text-based AI model, I am unable to directly provide a diagram. However, I can describe the conductive system of the heart and how action potentials spread throughout the cardiac muscle.
The conducting system in the heart is responsible for coordinating the contraction and relaxation of cardiac muscle cells, ensuring an efficient pumping action. The main components of this system include the sinoatrial (SA) node, atrioventricular (AV) node, bundle of His, right and left bundle branches, and Purkinje fibers.
1. Sinoatrial (SA) Node: The SA node is located in the upper wall of the right atrium near the opening of the superior vena cava. It acts as the primary pacemaker of the heart, generating action potentials spontaneously. The SA node sets the rhythm for the entire heart.
2. Atrioventricular (AV) Node: The AV node is located in the lower part of the right atrium near the interatrial septum. It receives the action potentials from the SA node and delays their transmission to allow for adequate atrial contraction before ventricular contraction.
3. Bundle of His: After passing through the AV node, the action potentials travel into the bundle of His. This bundle is a collection of specialized conducting fibers that travel along the interventricular septum, which separates the left and right ventricles.
4. Right and Left Bundle Branches: The bundle of His divides into the right and left bundle branches. These branches extend towards the apex of the heart, along the respective sides of the interventricular septum.
5. Purkinje Fibers: At the apex of the heart, the bundle branches divide into numerous smaller fibers called Purkinje fibers. These fibers spread throughout the ventricular myocardium, enabling rapid transmission of the action potentials.
When an action potential is generated by the SA node, it spreads across both atria, causing them to contract. The action potential is delayed at the AV node, allowing for complete atrial contraction and the filling of the ventricles. The action potential then travels down the bundle of His, bundle branches, and Purkinje fibers, rapidly spreading throughout the ventricular myocardium. This coordinated spread of action potentials ensures a synchronized contraction of the ventricles, resulting in effective pumping of blood out of the heart.
Remember, referring to a diagram or an illustration would provide a more comprehensive understanding of the system.