Peryksikköön

Peryksikköön is a Finnish term that translates to "pericardium" in English. The pericardium is a double-layered sac that surrounds the heart. The outer layer, the fibrous pericardium, is tough and inelastic, anchoring the heart to surrounding structures. The inner layer, the serous pericardium, is a delicate membrane that itself has two sub-layers. The parietal layer of the serous pericardium lines the inside of the fibrous pericardium, and the visceral layer, also known as the epicardium, is directly attached to the surface of the heart muscle.

Between these two layers of the serous pericardium is a potential space called the pericardial cavity. This cavity contains a small amount of pericardial fluid, which acts as a lubricant, allowing the heart to contract and relax smoothly without friction against the surrounding pericardial layers. The pericardium's primary functions are to protect the heart, limit its movement, prevent overstretching, and act as a barrier against infection. Conditions affecting the pericardium include pericarditis (inflammation) and pericardial effusion (excess fluid buildup).