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Pericardium

Pericardium

Overview
The pericardium is a double-walled sac that contains the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

 and the roots of the great vessels
Great vessels
Great vessels is a term used to refer collectively to the four large vessels that bring blood to and from the heart. These are:*Superior vena cava*Inferior vena cava*Pulmonary artery*AortaAll four pulmonary veins are considered apart of the great vessels...

.

There are two layers to the pericardial sac: the outermost fibrous pericardium
Fibrous pericardium
The fibrous pericardium is the most superficial layer of the pericardium. It is made up of dense connective tissue, a loose connective tissue which acts to protect the heart, anchoring it to the surrounding walls, and preventing it from overfilling with blood...

 and the inner serous pericardium
Serous pericardium
The serous pericardium is deeper than the fibrous pericardium. It contains two layers, both of which function in lubricating the heart to prevent friction from occurring during heart activity:...

. The serous pericardium, in turn, is divided into two layers, the parietal pericardium, which is fused to and inseparable from the fibrous pericardium, and the visceral pericardium, which is part of the epicardium
Epicardium
Epicardium describes the outer layer of heart tissue . When considered as a part of the pericardium, it is the inner layer, or visceral pericardium, continuous with the serous layer....

.
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Encyclopedia
The pericardium is a double-walled sac that contains the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

 and the roots of the great vessels
Great vessels
Great vessels is a term used to refer collectively to the four large vessels that bring blood to and from the heart. These are:*Superior vena cava*Inferior vena cava*Pulmonary artery*AortaAll four pulmonary veins are considered apart of the great vessels...

.

Layers


There are two layers to the pericardial sac: the outermost fibrous pericardium
Fibrous pericardium
The fibrous pericardium is the most superficial layer of the pericardium. It is made up of dense connective tissue, a loose connective tissue which acts to protect the heart, anchoring it to the surrounding walls, and preventing it from overfilling with blood...

 and the inner serous pericardium
Serous pericardium
The serous pericardium is deeper than the fibrous pericardium. It contains two layers, both of which function in lubricating the heart to prevent friction from occurring during heart activity:...

. The serous pericardium, in turn, is divided into two layers, the parietal pericardium, which is fused to and inseparable from the fibrous pericardium, and the visceral pericardium, which is part of the epicardium
Epicardium
Epicardium describes the outer layer of heart tissue . When considered as a part of the pericardium, it is the inner layer, or visceral pericardium, continuous with the serous layer....

. The epicardium is the layer immediately outside of the heart muscle proper (the myocardium).

The visceral layer extends to the beginning of the great vessels, becoming one with the parietal layer of the serous pericardium. This happens at two areas; where the aorta
Aorta
The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...

 and pulmonary trunk leave the heart and where the superior vena cava
Superior vena cava
The superior vena cava is truly superior, a large diameter, yet short, vein that carries deoxygenated blood from the upper half of the body to the heart's right atrium...

, inferior vena cava
Inferior vena cava
The inferior vena cava , also known as the posterior vena cava, is the large vein that carries de-oxygenated blood from the lower half of the body into the right atrium of the heart....

 and pulmonary veins enter the heart.

In between the parietal and visceral pericardial layers there is a potential space
Potential space
In anatomy, potential space refers to a space or cavity that can exist because two adjacent features that are not tightly adjoined, but does not appear during normal functioning.-Examples:* subdural space* vagina* pericardial cavity...

 called the pericardial cavity
Pericardial cavity
The pericardial cavity is a potential space between the parietal pericardium and visceral layer. It contains a supply of serous fluid. The serous fluid that is found in this space is known as the pericardial fluid....

. It is normally lubricated by a film of pericardial fluid. Too much fluid in the cavity (such as in a pericardial effusion
Pericardial effusion
Pericardial effusion is an abnormal accumulation of fluid in the pericardial cavity. Because of the limited amount of space in the pericardial cavity, fluid accumulation will lead to an increased intrapericardial pressure and this can negatively affect heart function...

) can result in pericardial tamponade (compression of the heart within the pericardial sac). A pericardectomy is sometimes needed in these cases.

Anatomical relationships

  • Surrounds heart and bases of pulmonary artery and aorta.
  • Deep to sternum and anterior chest wall.
  • The right phrenic nerve
    Phrenic nerve
    The phrenic nerve originates mainly from the 4th cervical nerve, but also receives contributions from the 5th and 3rd cervical nerves in humans....

     passes to the right of the pericardium.
  • The left phrenic nerve
    Phrenic nerve
    The phrenic nerve originates mainly from the 4th cervical nerve, but also receives contributions from the 5th and 3rd cervical nerves in humans....

     passes over the pericardium of the left ventricle.
  • Pericardial arteries supply blood to the dorsal portion of the pericardium.

Diseases/Abnormalities

  • Pericarditis
    Pericarditis
    Pericarditis is an inflammation of the pericardium . A characteristic chest pain is often present.The causes of pericarditis are varied, including viral infections of the pericardium, idiopathic causes, uremic pericarditis, bacterial infections of the precardium Pericarditis is an inflammation of...

     resulting in pericardial friction rub
    Pericardial friction rub
    A pericardial friction rub, also pericardial rub, is an audible medical sign used in the diagnosis of pericarditis. Upon auscultation, this sign is an extra heart sound of to-and-fro character, typically with three components, two systolic and one diastolic. It resembles the sound of squeaky...

  • Pericardial effusion
    Pericardial effusion
    Pericardial effusion is an abnormal accumulation of fluid in the pericardial cavity. Because of the limited amount of space in the pericardial cavity, fluid accumulation will lead to an increased intrapericardial pressure and this can negatively affect heart function...

     which may lead to cardiac tamponade
    Cardiac tamponade
    Cardiac tamponade, also known as pericardial tamponade, is an emergency condition in which fluid accumulates in the pericardium ....

    .
  • Cardiac Tamponade
    Cardiac tamponade
    Cardiac tamponade, also known as pericardial tamponade, is an emergency condition in which fluid accumulates in the pericardium ....

    as a primary pathology following traumatic injury.

External links

- "Mediastinum: Pericardium (pericardial sac)"