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.
STANFORD HISTORY EDUCATION GROUP sheg.stanford.edu Rise of the Roman Republic Timeline 509 BCE: Tarquin the Proud, the last king of Rome, was overthrown by a group of patricians upset over his abuse of power.19 BCE: Greek historian Polybius completed his Histories, detailing how Rome came to dominate the world. 30 BCE: Octavian defeated Mark Anthony and Cleopatra, conquering the last Greek kingdom in the world in Egypt. Octavian was appointed Augustus, the first emperor of Rome, signaling the end of the Roman Republic.