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What Is the Serous Pericardium?

S. Berger
S. Berger

Two sacs of mesothelial cells surround the heart, protecting it from friction during its normal activity. They also restrict the heart's motion, so that it does not contact other surfaces that could prove harmful. Finally, these sacs prevent nearby inflammations and infections from spreading to the heart. The deeper of the two is known as the serous pericardium, and it is divided into two layers. These are the parietal and visceral layers of the serous pericardium.

The parietal layer of the serous pericardium lies next to the fibrous pericardium, the outer sac protecting the heart. Although these linings are considered separate anatomical entities, they are actually joined together. The visceral layer is also joined to a surface, in this case, the outside of the heart.

Tuberculosis can lead to an increase in the amount of fluid in the pericardial sac.
Tuberculosis can lead to an increase in the amount of fluid in the pericardial sac.

Both layers, the parietal and visceral layers, rejoin one another at several points. These points are where the great vessels, such as the aorta and venae cavae, pass out of the heart. At these places, the serous pericardium joins the outer layers of these veins. This fusion with different membranes allows the pericardium to completely enclose the heart.

The pericardial cavity is a small space that separates the two layers. This cavity in the heart is filled with a serous fluid of proteins and water. Each layer of the serous pericardium produces this fluid, which is called pericardial fluid.

If pericardial fluid exerts pressure on the heart, it can restrict its movement.
If pericardial fluid exerts pressure on the heart, it can restrict its movement.

At times, trauma or conditions like tuberculosis may increase the amount of fluid in the pericardial sac. This is known as a pericardial effusion, and can be life-threatening. Depending on the cause, the pericardial effusion may dissipate on its own, but it may require surgical intervention. Normally, there is anywhere from 15 milliliters (ml) to 50 ml of pericardial fluid. An effusion that leads to more than 120 ml of fluid will create excess pressure on the heart.

Low blood pressure may occur if pericardial fluid exerts pressure on the heart.
Low blood pressure may occur if pericardial fluid exerts pressure on the heart.

If the pericardial fluid exerts pressure on the heart, it can restrict its movement. This can cause several negative effects, including low blood pressure and a drop in heart output. How quickly the fluid accumulates can influence the severity of this condition.

In the worst-case scenario, a cardiac tamponade, there is a rapid increase in fluid, coupled with a rapid decrease in cardiac activity. Ultimately, this can cause death. Usually, hemorrhages are the main cause of a cardiac tamponade, but there are other potential causes. These other disease states include tuberculosis, cancer, reactions to drugs, radiation therapy, or infection, or systemic lupus.

Discussion Comments

anon942500

Mu wife had lung cancer in 2011 and had surgery in October, 2011. She felt sick in November of 2013 and was treated with pneumonia, but still got a lot sicker. Now she's in the hospital in Halifax. They did a CT scan and saw liquid on the sac of the heart. They also inserted a tube to drain the fluid and 700 ml came out from the sac that surrounds the heart.

She's not too good and they don't know why she is so sick. Can you help me because I don't think that the hospital knows what they are doing. My wife lost over 50 pounds so far and she knows she's dying, Can you help me please?

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    • Tuberculosis can lead to an increase in the amount of fluid in the pericardial sac.
      By: stockdevil
      Tuberculosis can lead to an increase in the amount of fluid in the pericardial sac.
    • If pericardial fluid exerts pressure on the heart, it can restrict its movement.
      By: reineg
      If pericardial fluid exerts pressure on the heart, it can restrict its movement.
    • Low blood pressure may occur if pericardial fluid exerts pressure on the heart.
      By: mangostock
      Low blood pressure may occur if pericardial fluid exerts pressure on the heart.
    • A pericardial effusion may require surgical intervention.
      By: Tyler Olson
      A pericardial effusion may require surgical intervention.
    • Two sacs of mesothelial cells surround the heart, protecting it from friction during its normal activity, with deeper of the two known as the serous pericardium.
      By: arcticsilence
      Two sacs of mesothelial cells surround the heart, protecting it from friction during its normal activity, with deeper of the two known as the serous pericardium.