assignment. the intrinsic ability of cardiac muscle to generate action and potentials ( APs) rhythmically is achieved by the normal pace maker, the sino-atrial node (S-A node). the S-A node is party of the special excitatory and conductive system of cardiac muscle. with the help of a digram, describe this conductive system how the AP spread throughout the muscle.
The conductive system of cardiac muscle consists of several components that work together to spread action potentials (APs) throughout the muscle. The major components of this system include the sino-atrial node (S-A node), atrioventricular node (A-V node), bundle of His, bundle branches, and Purkinje fibers.
The S-A node is the primary pacemaker of the heart located in the right atrium near the opening of the superior vena cava. It initiates the electrical signals that regulate the heart's rhythm. The AP generated by the S-A node spreads through the atria, causing them to contract.
From the S-A node, the AP travels to the atrioventricular node (A-V node), located at the base of the right atrium near the atrioventricular septum. The A-V node acts as a delay station, allowing the atria to contract and fill the ventricles completely before transmitting the AP further.
Next, the AP passes through the bundle of His, a group of specialized cardiac muscle fibers, which then divides into the left and right bundle branches. These branches descend along the septum of the ventricles, towards the apex of the heart.
Finally, the bundle branches further divide into Purkinje fibers, which spread throughout the ventricular muscle. These fibers rapidly transmit the APs and cause the ventricles to contract, from the apex upwards, ensuring an efficient ejection of blood from the heart.
Here is a diagram illustrating the conductive system of cardiac muscle:
___ ___
/ \_/ \
| S-A node |
\___|___/
|
|Atria|
|
| A-V node |
___|___
/ \
| Bundle of |
| His |
\___|___/
|
|Bundle |
|Branches |
|
|Purkinje |
| Fibers |
|______|
This diagram shows the spread of APs from the initiation at the S-A node, through the atria, passing through the A-V node, bundle of His, bundle branches, and finally the Purkinje fibers, causing synchronized contraction of the cardiac muscle.