Endothelium refers to cells that line the interior surface of blood vessels and lymphatic vessels, forming an interface between circulating blood or lymph in the lumen and the rest of the vessel wall.
It is a thin layer of single-layered squamous cells, which are called the endothelial cells.
Endothelial cells are also the participants of the defense mechanism besides bone marrow and immune cells.
Endothelial cells play a role in immunity, inflammation, repair, and healing.
They are also significant cells to note in tissue grafting.
In this video, Dr. Mobeen Syed explains that the immune system is defending all the remaining cells besides immune cells, which make the human body.
Innate immune cells recognize the pathogen-infected cells in a specific way.
All the nucleated cells have MHC 1 on them.
The cells which are affected by pathogens and have less density of MHC 1 are called sick-cells.
The natural-killer cells are involved in the detection of pathogen-infected cells. Natural killer cells release perforins, granzymes, and defensins to kill the pathogen affected cells.
The following topics have discussed in the video:
* Role of endothelial cells in the immune system
* Role of natural killer cells in the immune system
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https://www.youtube.com/watch?v=3HcaMZr2Kfk