Mesothelial cells are a specialized type of cell that lines the body’s internal organs and cavities. These cells form a thin, protective membrane known as the mesothelium. This layer serves as a cushion and creates a slippery, non-adhesive surface, which is important for the proper movement of internal organs.
Where Mesothelial Cells Reside in the Body
Mesothelial cells are found in several major serous cavities, where they form distinct linings named for their location. One of the most extensive is the pleura, the membrane associated with the lungs. The pleura has two layers: one that covers the lungs directly and another that lines the interior of the chest wall.
Another primary location is the peritoneum, the membrane that lines the abdominal cavity. The peritoneum envelops numerous abdominal organs, including the stomach, intestines, and liver, ensuring they can move smoothly during digestion.
The heart is also encased by a mesothelial lining called the pericardium. This sac-like structure surrounds the heart, providing a protective barrier and allowing it to beat without friction. A less common location is the tunica vaginalis, a pouch of serous membrane that covers the testes and allows for their movement.
The Essential Roles of Mesothelial Cells
A primary function of mesothelial cells is to produce a lubricating fluid called serous fluid. This fluid fills the space between the layers of the mesothelium, reducing friction and allowing organs to glide past one another. For instance, this lubrication permits the lungs to expand and contract smoothly during breathing and the heart to beat unimpeded.
Mesothelial cells are also active participants in the body’s defense and repair systems. They help transport fluids and immune cells across the serous membranes. In response to injury or infection, these cells play a part in managing inflammation and can signal the presence of foreign invaders like bacteria.
These cells also contribute to tissue repair and regeneration following damage to the serous membranes. Although the mesothelium’s tissue is slow to renew, they are capable of repairing damaged areas to some extent. This healing ability helps maintain the integrity of the protective barrier they form.
When Mesothelial Cells Are Implicated in Disease
Mesothelial cells can be involved in several medical conditions, most notably malignant mesothelioma. This disease occurs when mesothelial cells undergo genetic mutations and begin to grow uncontrollably, forming tumors. The primary risk factor for developing mesothelioma is exposure to asbestos fibers, which can become lodged in the mesothelium and cause long-term damage.
Inflammatory conditions can also directly involve the mesothelium. Pleurisy, peritonitis, and pericarditis are terms for inflammation of the pleura, peritoneum, and pericardium. Such inflammation can cause a significant increase in the number of mesothelial cells in the serous fluid, which can be a sign of an underlying issue.
Damage to the mesothelium from surgery or severe inflammation can lead to the formation of adhesions. Adhesions are bands of scar tissue that can cause organs to stick to one another or to the cavity wall, impairing their normal function. When mesothelial cells are damaged, their protective functions are compromised, which can lead to fluid buildup, known as an effusion.