What is Pericardium, definition and function. Pericardium is a tough, two-layer membranous sac that encloses the HEART. The pericardiumâs fibrous outer layer, called the fibrous pericardium, protects the heart from contact with the chest wall and other structures in the chest, including the LUNGS and the sternum.he inner layer of the pericardium is a filmy envelope. Its two surfaces are the parietal pericardium, which contacts the fibrous pericardium, and the epicardium, which covers the MYOCARDIUM somewhat like a wet tissue. Inside the envelope is a watery fluid that lubricates the heart.
Roman Empire Timeline. Timeline Description: The Roman Empire was one of the greatest civilizations in history. It began in Rome in 753 BC. Rome controlled over two million square miles stretching from the Rhine River to Egypt and from Britain to Asia Minor. This timeline highlights the major events in the history of Ancient Rome.
This article is about the historiography of the decline of the Roman Empire. For a description of events, see Fall of the Western Roman Empire. For the historical era in general, see Late Antiquity. For the book by Edward Gibbon, see The History of the Decline and Fall of the Roman Empire.ibbon took September 4, 476 as a convenient marker for the final dissolution of the Western Roman Empire, when Romulus Augustus, the last Emperor of the Western Roman Empire, was deposed by Odoacer, a Germanic chieftain. Some modern historians question the significance of the year 476 for its end.