Difference Between Mesothelium and Endothelium

Main Difference – Mesothelium vs Endothelium

Mesothelium and endothelium are two types of membranes that line the body cavities of animals. Mesothelium is originated from mesoderm whereas endothelium is derived from ectoderm and endoderm in the early embryo. In adults, both mesothelium and endothelium are made up of simple squamous epithelium. The main difference between mesothelium and endothelium is that, in adults, mesothelium occurs in all serous membranes of the body such as pericardium, peritoneum, and pleura and internal reproductive organs whereas the endothelium lines the inner surface of the blood vessels, lymphatic vessels, and the heart. Therefore, mesothelium is the middle covering of the body whereas endothelium is the inner covering.     

Key Areas Covered

1. What is Mesothelium
      – Definition, Location, Characteristics, Function
2. What is Endothelium
      – Definition, Location, Characteristics, Function
3. What are the Similarities Between Mesothelium and Endothelium
      – Outline of Common Features
4. What is the Difference Between Mesothelium and Endothelium
      – Comparison of Key Differences

Key Terms: Blood Vessels, Endothelium, Heart, Lungs, Lymphatic Vessels, Mesothelium, Pericardium, Peritoneum, Pleura

Difference Between Mesothelium and Endothelium - Comparison Summary

What is Mesothelium

Mesothelium is the epithelium that lines the peritoneum, pericardium, and pleura. Mesothelial cells originate from the mesoderm. The peritoneum is the serous membrane which lines the abdominal cavity. The visceral peritoneum and the parietal peritoneum are the two categories of the peritoneum. The visceral peritoneum lines the internal organs whereas the parietal peritoneum lines the pelvic and the abdominal cavities. Both types of peritonea are lined by mesothelial cells. Pericardium is the lining of the heart and the mediastinum. The mediastinum is the area between the lungs.  The pleura is the lining around the lungs. The visceral pleura and the parietal pleura are the two types of pleura. The visceral pleura directly lies over the lungs whereas the parietal pleura is the outer layer of the lungs.

Difference Between Mesothelium and Endothelium

Figure 1: Mesothelial Cells

The main function of the mesothelium in the peritoneum, pericardium, and the pleura is to provide a slippery but, non-sticky surface between the organs, protecting the organs in the chest and the abdomen and allowing the functioning of the organs. Other than that, the mesothelium allows the movement of fluids and substances between the internal organs and the outer environment. It also helps in blood clotting and tissue healing. The mesothelium also plays an immunological role against infections and the formation of tumors. Mesothelioma, adhesions, fibrosis, and pleural effusions are the common complications of the mesothelium.

What is Endothelium

Endothelium is the epithelium that lines the cavities of various organs such as blood vessels, lymphatic vessels, and the heart. It can originate from either endoderm or ectoderm. Arteries and veins are the major blood vessels that carry blood throughout the body. All lumens of the blood vessels and lymphatic vessels are lined by a single layer of the endothelial cells, which are attached to the basal lamina. Since endothelial cells line the cavities of the heart as well, the whole circulatory system can be considered as lined by the endothelial cells. Those endothelial cells are squamous epithelial cells. The structure of the endothelium is shown in figure 2.

Main Difference - Mesothelium vs Endothelium

Figure 2: Endothelium

The main function of the endothelium is also to provide a slippery but, non-sticky surface for the flow of the blood. It allows the movement of white blood cells from the blood into the tissues by acting as a semi-selective barrier. The endothelium is involved in the formation of the blood vessels and blood clotting. It controls the blood pressure by involving in the vasoconstriction and vasodilation.

Similarities Between Mesothelium and Endothelium

  • Both mesothelium and endothelium line the body cavities.
  • Both mesothelium and endothelium are made up of simple squamous epithelium.
  • Both mesothelium and endothelium provide non- sticky, friction-reduced lining into the body cavity.

Difference Between Mesothelium and Endothelium

Definition

Mesothelium: Mesothelium is the epithelium that lines the peritoneum, pericardium, and pleura.

Endothelium: Endothelium is the epithelium that lines the cavities of various organs such as blood vessels, lymphatic vessels, and the heart.

Middle/Inner Covering

Mesothelium: Mesothelium is the middle covering of the body.

Endothelium: Endothelium is the inner covering of the body.

Location

Mesothelium: Mesothelium is found in all the serous membranes of the body such as pericardium, peritoneum, and pleura and internal reproductive organs.

Endothelium: Endothelium lines the inner surface of the blood vessels, lymphatic vessels and the heart.

Origin

Mesothelium: Mesothelium is originated from the mesoderm.

Endothelium: Endothelium is originated from ectoderm or endoderm.

Conclusion

Mesothelium and endothelium are two types of epithelia that are made up of simple squamous epithelium. The mesothelium is originated from the mesoderm while the endothelium is originated from the ectoderm or endoderm. The mesothelium is found in the peritoneum, pericardium, and the pleura. The endothelium lines the cavities of the circulatory system. The main difference between mesothelium and endothelium is the occurrence of each type of the epithelia in the body.

Reference:

1. Eldridge, MD Lynne. “What is the Mesothelium and What is It’s Function?” Verywell, Available here. Accessed 2 Oct. 2017.
2. Alberts, Bruce. “Blood Vessels and Endothelial Cells.” Molecular Biology of the Cell. 4th edition., U.S. National Library of Medicine, 1 Jan. 1970, Available here. Accessed 2 Oct. 2017.

Image Courtesy:

1. “Mesothelium peritoneal wash high mag” By Nephron – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Blausen 0055 ArteryWallStructure” By “Medical gallery of Blausen Medical 2014″. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. – Own work (CC BY 3.0) via Commons Wikimedia (Cropped)

About the Author: Lakna

Lakna, a graduate in Molecular Biology & Biochemistry, is a Molecular Biologist and has a broad and keen interest in the discovery of nature related things

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