Anatomy
Fact-checked

At TheHealthBoard, we're committed to delivering accurate, trustworthy information. Our expert-authored content is rigorously fact-checked and sourced from credible authorities. Discover how we uphold the highest standards in providing you with reliable knowledge.

Learn more...

What is the Endothelium?

Niki Foster
Niki Foster
Niki Foster
Niki Foster

The endothelium is a thin layer of epithelial cells lining the inside of the blood vessels. It lines the entire circulatory system, including the heart and all the veins, arteries, and capillaries. The endothelium lining the heart is also called the endocardium, though it is similar to the tissue the lining blood vessels. The endothelium forms a barrier between the blood and the other structures of the circulatory system, allowing the blood to flow more smoothly, and therefore to circulate more quickly throughout the body.

The endothelium is simple squamous epithelium, meaning that it consists of a single layer of flat, or squamous, epithelial cells, making it the thinnest possible type of membrane. This single layer of cells may also be referred to as a monolayer. An epithelium in general is any type of tissue that serves to line the surface or cavity of any structure in the body. Epithelium is one of the four primary tissue types in the human body, the others being connective tissue, nervous tissue, and muscle tissue.

A diagram showing the composition of a blood vessel. The endothelium lines the inside of the vessels.
A diagram showing the composition of a blood vessel. The endothelium lines the inside of the vessels.

The endothelium is involved in a number of important functions. It helps control blood pressure through vasodilation and vasoconstriction, the widening and constricting of the blood vessels respectively. It also aids in blood clotting, minimizing damage and blood loss in the case of wounds.

Other endothelial functions include angiogenesis, or the growth of new blood vessels, and serving as a barrier by selectively allowing certain materials to exit or enter the bloodstream. In addition to the above functions, the endocardium also controls the development of the heart muscle in the embryo and into adulthood. It is also responsible for regulating the function of the myocardium, or the heart muscle.

Endothelium is a thin layer of epithelial cells that line the blood vessels of the entire circulatory system.
Endothelium is a thin layer of epithelial cells that line the blood vessels of the entire circulatory system.

The endothelium can also be involved in a variety of disorders. Both inflammation, an immune response characterized by redness and swelling, and atherosclerosis, in which the blood vessels become clogged with a fatty buildup that impedes blood flow, involve the endothelium. Endothelial dysfunction, in which the endothelium ceases to work properly, is an early sign of atherosclerosis, in addition to other circulatory system disorders. Loss of healthy endothelial function is also associated with smoking, coronary artery disease, diabetes mellitus, hypercholesterolemia, and hypertension or high blood pressure. Endothelial disfunction is typically an indicator of future cardiovascular problems.

A loss of healthy endothelial function can trigger hypertension, also known as high blood pressure.
A loss of healthy endothelial function can trigger hypertension, also known as high blood pressure.

The endocardium is sometimes affected in cases of myocardial infarction, or heart attack. In such cases, the tissue can become damaged due to ischemia, or insufficient blood supply. Another disorder affecting the myocardium is infective endocarditis, or bacterial infection of the myocardium. Infective endocarditis can cause symptoms including fever, heart murmur, hemorrhaging, and blood in the urine.

Niki Foster
Niki Foster

In addition to her role as a TheHealthBoard editor, Niki enjoys educating herself about interesting and unusual topics in order to get ideas for her own articles. She is a graduate of UCLA, where she majored in Linguistics and Anthropology.

Learn more...
Niki Foster
Niki Foster

In addition to her role as a TheHealthBoard editor, Niki enjoys educating herself about interesting and unusual topics in order to get ideas for her own articles. She is a graduate of UCLA, where she majored in Linguistics and Anthropology.

Learn more...

Discussion Comments

jabuka

An intersting bit of information I came across regarding endothelial cells is that the cells can be tested for their health.

It appears that a simple test, a finger sesor, can predict future problems. It depends on the result of the test, low test score is an indication of poor endothelial health in outwardly healthy people.

It seems as great test to me that should be performed on most adults. It might spur people to healthier habits while there is still time.

Post your comments
Login:
Forgot password?
Register:
    • A diagram showing the composition of a blood vessel. The endothelium lines the inside of the vessels.
      By: Balint Radu
      A diagram showing the composition of a blood vessel. The endothelium lines the inside of the vessels.
    • Endothelium is a thin layer of epithelial cells that line the blood vessels of the entire circulatory system.
      By: 3drenderings
      Endothelium is a thin layer of epithelial cells that line the blood vessels of the entire circulatory system.
    • A loss of healthy endothelial function can trigger hypertension, also known as high blood pressure.
      By: dambuster
      A loss of healthy endothelial function can trigger hypertension, also known as high blood pressure.
    • Endothelium helps to control blood pressure, and a loss of it can cause high blood pressure.
      By: Minerva Studio
      Endothelium helps to control blood pressure, and a loss of it can cause high blood pressure.
    • Infective endocarditis may cause heart murmurs.
      By: aykuterd
      Infective endocarditis may cause heart murmurs.
    • The endothelium lining the heart is also called the endocardium.
      By: pankajstock123
      The endothelium lining the heart is also called the endocardium.
    • The endocardium is sometimes affected by a heart attack.
      By: WavebreakmediaMicro
      The endocardium is sometimes affected by a heart attack.