Difference Between Endothelium and Mesothelium

The key difference between endothelium and mesothelium is that the endothelium is the simple squamous epithelial cell layer that lines the entire circulatory system including blood vessels, lymph vessels and the heart while the mesothelium is the simple squamous epithelial cell layer that lines major body cavities such as the peritoneum, pleura and pericardium.

Epithelium, mesothelium and endothelium are three types of cell layers that line our internal organs, body cavities and the skin. Hence, they all are protective barriers of the body. Structurally, mesothelium and endothelium are specialized or modified epithelial layers with mesodermal origin. Accordingly, they are made up of simple squamous epithelial cells.  Both mesothelium and endothelium are single layered tissues. They line certain internal surfaces.

CONTENTS

1. Overview and Key Difference
2. What is Endothelium
3. What is Mesothelium
4. Similarities Between Endothelium and Mesothelium
5. Side by Side Comparison – Endothelium vs Mesothelium in Tabular Form
6. Summary

What is Endothelium?

The endothelium is a thin layer of supporting connective tissue that lines the internal surfaces of blood vessels, lymph vessels and the heart. It is a type of specialized epithelium that composes simple squamous epithelial cells. Furthermore, it consists of a single flattened cell layer. Since it lines the internal surfaces of the circulatory system, it has direct contact with the blood, lymph fluid and the circulating cells. Other than in the circulatory system, the endothelium is found in the inner lining of the cornea as well.

Figure 01: Endothelium

Similar to mesothelium, endothelium has a mesodermal origin. Furthermore, based on the cell arrangements in the endothelium, it can be continuous endothelium or fenestrated endothelium.

What is Mesothelium?

Mesothelium is also a specialized epithelium that lines major cavities of the body such as peritoneum, pericardium, mesentery, pelvis and pleura. Similar to endothelium, it is a tissue which has a mesodermal origin. Also, it consists of squamous epithelial cells arranged in a single continuous layer.

Figure 02: Mesothelial Cells

Moreover, the major function of the mesothelium is the protection of internal structures and aiding in movement and breathing. It provides a slippery, non-adhesive and protective surface to the internal structures. Not only protection, but mesothelial cells are also important for transporting of fluid and cells across the serosal cavities, antigen presentation, inflammation and tissue repair, coagulation and fibrinolysis and tumour cell adhesion, etc.

What are the Similarities Between Endothelium and Mesothelium?

• Endothelium and Mesothelium are specialized epithelial cell layers that line certain internal surfaces.
• They have a single cell layer.
• Also, both have a mesodermal origin.
• Furthermore, both contain squamous shaped cells (very thin flattened cells).

What is the Difference Between Endothelium and mesothelium?

Endothelium and mesothelium are two types of tissues that line certain internal surfaces. Endothelium lines the circulatory system while the mesothelium lines the major body cavities. Therefore, this is the key difference between endothelium and mesothelium. Endothelium covers the internal surfaces of blood vessels, lymph vessels and the heart while the mesothelium covers peritoneum, pleura and pericardium.

Moreover, endothelium fulfils important function including acting as a protective barrier, involving in inflammation, blood clotting, the formation of blood cells, controlling blood pressure, etc. On the other hand, mesothelium provides a  slippery, non-adhesive and protective surface to the internal structures and also they are important for transporting of fluid and cells across the serosal cavities, antigen presentation, inflammation and tissue repair, coagulation and fibrinolysis and tumour cell adhesion, etc. Hence, this is a functional difference between endothelium and mesothelium.

Below infographic describes the difference between endothelium and mesothelium in tabular form.

Summary – Endothelium vs Mesothelium

Endothelium and mesothelium are two types of specialized epithelial tissues composed of simple squamous epithelial cell layers and line certain internal surfaces of the body. However, endothelium lines the internal surfaces of the blood vessels, lymph vessels and the heart. But, mesothelium lines the internal surfaces of the major body cavities such as peritoneum, pericardium and pleura. Thus, this summarizes the difference between endothelium and mesothelium.

Reference:

1. Félétou, Michel. “The Endothelium.” Current Neurology and Neuroscience Reports., U.S. National Library of Medicine, 1 Jan. 1970. Available here   
2. Eldridge, Lynne. “What Is the Mesothelium and What Is It’s Function?” Verywell Health, Verywellhealth. Available here  

Image Courtesy:

1.”Endotelijalna ćelija”By DRosenbach at English Wikipedia, (CC BY-SA 3.0) via Commons Wikimedia  
2.”Mesothelium peritoneal wash high mag”By Nephron – Own work, (CC BY-SA 3.0) via Commons Wikimedia

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