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.
The Pax Romana (27 BC-180 AD) was a period of relative political stability in the Roman Empire which started with the creation of rule by emperors by Augustus after the civil â¦ wars of the Late Roman Republic.he Pax Romana was a period of of relative political stability. It was followed by the political instability of the crisis of the 3rd century. it was also the beginning of the decline of the Roman Empire which lasted for nearly 300 years.