A thin layer of flat cells that lines the inside of blood vessels and lymph vessels, acting as a barrier between blood and vessel walls.
From Greek 'endo-' (inside) and 'thele' (nipple), coined in the 1870s by Swiss anatomist Wilhelm His to describe the innermost lining of blood vessels because he initially thought it resembled a nipple-like structure.
Your endothelium is constantly working to keep blood flowing smoothly—when it gets damaged by smoking or high cholesterol, it can lead to heart disease, which is why this single layer of cells is so critical to staying healthy.
Complete word intelligence in one call. Free tier — 50 lookups/day.