The myocardium is the muscular heart wall itself, while the parietal pericardium is a layer of the pericardium that surrounds and protects the heart.
Here's a breakdown of the differences:
Myocardium vs. Parietal Pericardium
To clearly understand the difference, let's examine each component separately and then compare them:
Myocardium
- Definition: The myocardium ("muscle heart") is the thick muscular wall of the heart.
- Composition: Primarily composed of cardiac muscle tissue.
- Function: Responsible for the heart's pumping action, contracting to eject blood and relaxing to fill with blood.
- Location: Forms the bulk of the heart wall itself.
Parietal Pericardium
- Definition: A layer of the serous pericardium.
- Composition: A membrane lining the pericardial cavity.
- Function: Along with the visceral pericardium (epicardium), it secretes serous fluid that lubricates the heart, reducing friction as it beats. It also provides a protective sac around the heart. The parietal layer is continuous with the visceral layer of the serous pericardium or epicardium , which lies on the heart and is considered a part of the heart wall.
- Location: Forms the outer layer of the pericardium, the sac surrounding the heart.
Key Differences in a Table
| Feature | Myocardium | Parietal Pericardium |
|---|---|---|
| Primary Tissue | Cardiac Muscle | Serous Membrane |
| Main Function | Pumping blood | Protection and lubrication of the heart |
| Location | Forms the heart wall | Outer layer of the pericardial sac surrounding the heart |
