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Mesothelium
Table Of Contents
The mesothelium is a protective membrane that covers the lungs, abdomen, heart and testes. Mesothelioma cancer can develop in the mesothelium as a result of asbestos exposure.
Written by Karen Selby, RN | Medically Reviewed By Dr. Andrea Wolf | Edited By Walter Pacheco | Last Update: June 27, 2024
Written by Karen Selby, RN | Medically Reviewed By Dr. Andrea Wolf | Edited By Walter Pacheco | Last Update: June 27, 2024
What Is the Mesothelium?
The mesothelium is a layer of cells that covers and protects organs and tissue in the body. It also helps regulate response to injury, infection and disease.
Research suggests that it may have other functions, as well. The mesothelium may play a role in transporting fluid and controlling inflammation.
The mesothelium membrane can be distinguished based on the organs or body parts it covers.
Different Types of Mesothelium
- The pleural mesothelium covers the lungs and chest wall
- The peritoneal (parietal) mesothelium covers the abdominal organs and abdominal wall
- The pericardial mesothelium covers the heart
- The tunica vaginalis covers the testes
Asbestos can harm the mesothelium. Once inhaled or ingested, the toxic fibers become stuck and irritate cells and tissue over time.
Research suggests that the lymphatic system may play a role. With help from the lymph system, fibers may travel to the mesothelium.
Asbestos exposure can cause mesothelioma and other asbestos-related diseases in the mesothelium.
Mesothelium Structure and Function
The mesothelium includes two layers.
- The visceral layer covers the organ
- The parietal layer covers the body cavity
Mesothelial cells comprise these layers. These cells are a type of epithelial cell. They appear flat and squamous-like.
Quick Fact:
The mesothelium is a slowly renewing tissue. Less than 1% of the cells undergo cell division at any one time.
The primary function of the mesothelium is to provide a protective surface. This surface is flexible and not restrictive of the organs it covers.
Functions of the Mesothelium
- Transporting fluids and cells
- Inflammation and tissue repair
- Protection against invading microorganisms
- Presenting antigens (immune proteins) to lymphocytes (immune cells)
- Blood clotting to heal wounds
- Tumor cell adhesion to prevent cancerous spreading
Diseases of the Mesothelium
Cancer can develop in the mesothelium after inflammation and scarring. If the damage does not heal, the mesothelium can develop fibrous adhesions. These changes in mesothelial cells lead to malignant mesothelioma and other cancers.
Effusions are the accumulation of fluid between the layers of the mesothelium. They can develop as a result of inflammation and cancer in the mesothelium. Effusions are a symptom of mesothelial diseases, but they are not a primary condition.
- Pleural effusion accumulates around the lungs.
- Peritoneal effusion accumulates around the abdomen.
Pleural Diseases
Benign and cancerous diseases of the pleura can develop as a result of asbestos exposure.
- Pleuritis is inflammation of the pleura.
- Pleural plaques are fibrous scar tissue on the pleura that may become calcified.
- Pleural thickening is extensive scarring that thickens and restricts the pleura.
- Atelectasis is a contraction of pleural scar tissue that folds the pleura into the lung. This causes the lungs to underinflate.
- Pleural mesothelioma is cancer of the pleura.
Peritoneal Diseases
Benign and cancerous diseases can also develop in the peritoneum.
- Peritonitis is inflammation of the peritoneum.
- Peritoneal mesothelioma is cancer of the peritoneum.
- Primary peritoneal serous carcinoma is another cancer of the peritoneum.
Asbestos exposure is the primary cause of peritoneal mesothelioma. Peritonitis is inflammation of the peritoneum. Bacterial or fungal infections are the most common causes.
Primary peritoneal serous carcinoma is a type of cancer that can also occur in this area. A 2022 study likened it to advanced-stage serous ovarian carcinoma.
Pericardial Diseases
Several benign conditions and cancers can develop in the pericardium.
- Pericarditis is inflammation of the pericardium.
- Cardiac tamponade is compression of the heart by fluid accumulation.
- Pericardial constriction is scarring and a loss of elasticity of the pericardium.
- Pericardial mesothelioma is cancer of the pericardium.
- Several other cancers can develop in the pericardium, including sarcomas, lymphoma and primitive neuroectodermal tumor.
Tunica Vaginalis Diseases
Benign and cancerous diseases can develop in the tunica vaginalis.
- Hydrocele is an abnormal amount of fluid between the layers of the tunica vaginalis.
- Scrotal calculi are calcified deposits that form between the layers of the tunica vaginalis.
- Fibrous pseudotumors are benign lesions of the tunica vaginalis.
- Testicular mesothelioma is cancer of the tunica vaginalis.
- Several other cancers can develop in the tunica vaginalis including mesenchymal tumors, lymphomas and serous borderline tumors.
- A few benign tumors can develop as well, including adenomatoid tumor, scrotal tunica cyst, lipoma and leiomyoma.
The mesothelium protects organs and responds to inflammation, injury and disease.
Make an appointment with your doctor if you have a history of asbestos exposure and develop abnormal symptoms affecting the lungs, abdomen, heart or testes.
Recommended Reading
The Nation's Top Mesothelioma Guide
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