Related Experiment Videos
The ultrastructure of human abdominal mesothelium
N J Slater1, A T Raftery, G H Cope
1Renal and Transplant Unit, Royal Hallamshire Hospital, Sheffield, UK.
Abstract:
Fresh specimens of human peritoneum collected from heart-beating cadaver organ donors have been examined by transmission electron microscopy. Samples were taken from the anterior abdominal wall and from the surfaces of the liver, stomach and diaphragm. The mesothelium consisted of a single layer of flattened cells generally 2.5 microns to 3 microns thick. These were joined by tight junctions and desmosomes to form a continuous sheet. The cells rested on a prominent basement membrane deep to which was a layer of fibrous connective tissue. This layer was more compact under the mesothelium from the abdominal wall and liver than elsewhere. Long microvilli projected from apical surface of the cells. In many cases these covered the entire surface but sometimes they were more profuse at the edges of the cells near the intercellular junctions. The cells possessed a well-developed cytoskeleton of intermediate filaments which coursed through the cytoplasm in thick bundles. The cells also had a well-developed rough endoplasmic reticulum and Golgi apparatus. Numerous smooth-surfaced and coated vesicles could be seen adjacent to the plasmalemma at all surfaces, providing evidence of considerable pinocytotic activity. There was little regional variation in the structure of the mesothelium. We found no evidence of pores passing through the layer although, on the liver, cisternae were present between the cells and these were often occupied by lymphocytes.
Insights
Human peritoneum mesothelium, examined via electron microscopy, forms a continuous sheet of flattened cells with microvilli and significant pinocytotic activity, showing minimal regional variation.
Area of Science:
- Human anatomy
- Cell biology
- Histology
Background:
- The peritoneum is a serous membrane lining the abdominal cavity.
- Understanding its cellular structure is crucial for various physiological and pathological processes.
Purpose of the Study:
- To investigate the ultrastructure of human peritoneum mesothelium.
- To identify regional variations in mesothelial cell morphology.
Main Methods:
- Transmission electron microscopy (TEM) was used.
- Specimens were obtained from heart-beating cadaver organ donors.
- Samples were collected from the anterior abdominal wall, liver, stomach, and diaphragm surfaces.
Main Results:
- Mesothelium consists of a single layer of flattened cells (2.5–3 μm thick) joined by tight junctions and desmosomes.
- Cells rest on a basement membrane and underlying fibrous connective tissue, which is more compact under the abdominal wall and liver.
- Apical surfaces feature long microvilli; cells exhibit well-developed cytoskeleton, rough endoplasmic reticulum, Golgi apparatus, and vesicles indicating pinocytotic activity.
- Little regional variation was observed, with no pores found, though liver mesothelium showed intercellular cisternae occupied by lymphocytes.
Conclusions:
- Human peritoneum mesothelium presents a uniform structure across different abdominal locations.
- The observed features, including microvilli and pinocytotic activity, suggest a role in fluid and solute transport.
- Lymphocyte presence in liver mesothelial cisternae warrants further investigation.