21.2 The Pericardium

• • The heart sits within the mediastinum, located between the two pleural cavities. The pericardium, which surrounds the heart, is composed of a fibrous pericardium and a serous pericardium.
• The mediastinum contains the great vessels, which are attached at the base of the heart, thymus, esophagus, trachea
• The pericardium surrounds the heart
• The pericardium is composed of an outer fibrous pericardium and an inner serous pericardium
• The fibrous pericardium

  • composed of dense network of collagen fibers
  • stabilize position of heart and vessels within mediastinum
• The lining of the pericardium is the serous pericardium
• This two layered membrane called serous pericardium is composed of

  • outer parietal layer
  • inner visceral layer
• The visceral layer is also known as the epicardium
• The potential, fluid filled space between the parietal layer and the visceral layer (both of the serous pericardium) is the pericardial cavity
• The pericardial cavity contains pericardial fluid
• Pericardial fluid

  • secreted by pericardial membranes
  • acts as a lubricant
  • reduces friction between visceral and parietal surfaces as heart beats
• SUMMARY

  • Heart surrounded by pericardium and lies within anterior of mediastinum, separates two pleural cavities
  • Pericardial cavity is lined by pericardium and contains lubricating fluid called pericardial fluid
  • Visceral layer of serous pericardium, also known as epicardium, covers heart's surface and parietal layer of serous pericardium lines inner surface