All Topics  
Endothelium

 

 
   Email Print
   Bookmark   Link
 

 

Endothelium
 
 
  Topics Endothelium Topic Home



The endothelium is the thin layer of cells
Cell (biology)

The cell is the structural and functional unit of all known Life organisms. It is the smallest unit of an organism that is classified as living, and is often called the building bricks of life....
 that line the interior surface of blood vessel
Blood vessel

The blood vessels are the part of the circulatory system that transport blood throughout the body. There are three major types of blood vessels: the artery, which carry the blood away from the heart, the capillary, which enable the actual exchange of water and chemicals between the blood and the tissues; and the veins, which carry blood from...
s, forming an interface between circulating blood
Blood

Blood is a specialized bodily fluid that delivers necessary substances to the body's Cell s ? such as nutrients and oxygen ? and transports waste products away from those same cells....
 in the lumen
Lumen (anatomy)

A lumen in biology is the inside space of a tubular structure, such as an artery or intestine. By extension, a lumen can also be the inside space of a cellular component or structure, such as the endoplasmic reticulum....
 and the rest of the vessel wall. Endothelial cells line the entire circulatory system
Circulatory system

The circulatory system is an organ that moves nutrients, gases, and wastes to and from cells to help fight diseases and help stabilize body temperature and pH to maintain homeostasis....
, from the heart
Heart

The heart is a muscle organ in all vertebrates responsible for pumping blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in annelids, mollusks, and arthropods....
 to the smallest capillary
Capillary

Capillaries are the smallest of a body's blood vessels, measuring 5-10 micrometre in diameter, which connect arterioles and venules, and enable the interchange of water, oxygen, carbon dioxide, and many other nutrient and waste chemical substances between blood and surrounding tissue s....
.






Discussion
Ask a question about 'Endothelium'
Start a new discussion about 'Endothelium'
Answer questions from other users
Full Discussion Forum



Encyclopedia


Anatomy Artery


The endothelium is the thin layer of cells
Cell (biology)

The cell is the structural and functional unit of all known Life organisms. It is the smallest unit of an organism that is classified as living, and is often called the building bricks of life....
 that line the interior surface of blood vessel
Blood vessel

The blood vessels are the part of the circulatory system that transport blood throughout the body. There are three major types of blood vessels: the artery, which carry the blood away from the heart, the capillary, which enable the actual exchange of water and chemicals between the blood and the tissues; and the veins, which carry blood from...
s, forming an interface between circulating blood
Blood

Blood is a specialized bodily fluid that delivers necessary substances to the body's Cell s ? such as nutrients and oxygen ? and transports waste products away from those same cells....
 in the lumen
Lumen (anatomy)

A lumen in biology is the inside space of a tubular structure, such as an artery or intestine. By extension, a lumen can also be the inside space of a cellular component or structure, such as the endoplasmic reticulum....
 and the rest of the vessel wall. Endothelial cells line the entire circulatory system
Circulatory system

The circulatory system is an organ that moves nutrients, gases, and wastes to and from cells to help fight diseases and help stabilize body temperature and pH to maintain homeostasis....
, from the heart
Heart

The heart is a muscle organ in all vertebrates responsible for pumping blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in annelids, mollusks, and arthropods....
 to the smallest capillary
Capillary

Capillaries are the smallest of a body's blood vessels, measuring 5-10 micrometre in diameter, which connect arterioles and venules, and enable the interchange of water, oxygen, carbon dioxide, and many other nutrient and waste chemical substances between blood and surrounding tissue s....
. These cells reduce turbulence
Turbulence

In fluid dynamics, turbulence or turbulent flow is a fluid regime characterized by chaotic, stochastic property changes. This includes low momentum diffusion, high momentum convection, and rapid variation of pressure and velocity in space and time....
 of the flow of blood allowing the fluid to be pumped farther.

Endothelial tissue is a specialized type of epithelium
Epithelium

In biology and medicine, epithelium is a Biological tissue composed of cell s that line the cavities and surfaces of structures throughout the body....
 tissue (one of the four types of biological tissue
Biological tissue

Tissue is a cellular organizational level intermediate between cells and a complete organism. Hence, a tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function....
 in animals). More specifically, it is simple squamous epithelium
Squamous epithelium

In anatomy, squamous epithelium is an epithelium characterised by its most superficial layer consisting of flat, scale-like cell called squamous cell....
.

Terminology

The foundational model of anatomy makes a distinction between endothelial cells and epithelial cells on the basis of which tissues they develop from and states that the presence of vimentin rather than keratin filaments separate these from epithelial cells.

Endothelium of the interior surfaces of the heart chambers are called endocardium
Endocardium

The endocardium is the innermost layer of tissue that lines the chambers of the heart. Its Cell , embryology and biology, are similar to the endothelium cells that line blood vessels....
. Both blood and lymphatic capillaries are composed of a single layer of endothelial cells called a monolayer.

Function


Endothelial cells are involved in many aspects of vascular biology, including:

  • Vasoconstriction
    Vasoconstriction

    Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, particularly the large arteries, arterioles and veins....
     and vasodilation
    Vasodilation

    Vasodilation refers to the widening of blood vessels resulting from relaxation of smooth muscle cells within the vessel walls, particularly in the large arteries, smaller arterioles and large veins....
    , and hence the control of blood pressure
    Blood pressure

    Blood pressure is the pressure exerted by circulating blood on the walls of blood vessels, and constitutes one of the principal vital signs. The pressure of the circulating blood decreases as it moves away from the heart through artery and capillary, and toward the heart through veins....
  • Blood clotting
    Coagulation

    Coagulation is a complex process by which blood forms clots. It is an important part of hemostasis , wherein a damaged blood vessel wall is covered by a platelet and fibrin-containing clot to stop hemorrhage and begin repair of the damaged vessel....
     (thrombosis
    Thrombosis

    Thrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel is injured, the body uses platelets and fibrin to form a blood clot, because the first step in repairing it is to prevent loss of blood....
     & fibrinolysis
    Fibrinolysis

    Fibrinolysis is the process wherein a fibrin thrombus, the product of coagulation, is broken down. Its main enzyme plasmin cuts the fibrin mesh at various places, leading to the production of circulating fragments that are cleared by other proteases or by the kidney and liver....
    )
  • Atherosclerosis
    Atherosclerosis

    Atherosclerosis is a syndrome affecting artery blood vessels. It is a chronic inflammatory response in the walls of arteries, in large part due to the accumulation of macrophage white blood cells and promoted by low density lipoproteins without adequate removal of fats and cholesterol from the macrophages by functional high density lipoprot...
  • Formation of new blood vessels (angiogenesis
    Angiogenesis

    Angiogenesis is a physiological process involving the growth of new blood vessels from pre-existing vessels. Though there has been some debate over this, vasculogenesis is the term used for spontaneous blood-vessel formation, and Intussusception is the term for new blood vessel formation by splitting off existing ones....
    )
  • Inflammation
    Inflammation

    Inflammation is the complex biological response of Blood vessel tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. It is a protective attempt by the organism to remove the injurious stimuli as well as initiate the healing process for the tissue....
  • Barrier function - the endothelium acts as a selective barrier between the vessel lumen and surrounding tissue, controlling the passage of materials and the transit of white blood cell
    White blood cell

    White blood cells , or leukocytes , are cell of the immune system defending the body against both infectious disease and foreign materials....
    s into and out of the bloodstream. Excessive or prolonged increases in permeability of the endothelial monolayer, as in cases of chronic inflammation, may lead to tissue oedema/swelling.


In some organs, there are highly differentiated endothelial cells to perform specialized 'filtering' functions. Examples of such unique endothelial structures include the renal glomerulus and the blood-brain barrier
Blood-brain barrier

The blood-brain barrier is a metabolic or cellular structure in the central nervous system that restricts the passage of various chemical substances and microscopic objects between the bloodstream and the neural tissue itself, while still allowing the passage of substances essential to metabolism function ....
.

Pathology


Endothelial dysfunction
Endothelial dysfunction

Endothelial dysfunction is a physiological dysfunction of normal biochemical processes carried out by the endothelium, the cells that line the inner surface of all blood vessels including arteries and veins Compromise of normal function of endothelial cells is characteristic of endothelial dysfunction....
, or the loss of proper endothelial function, is a hallmark for vascular diseases, and often leads to atherosclerosis
Atherosclerosis

Atherosclerosis is a syndrome affecting artery blood vessels. It is a chronic inflammatory response in the walls of arteries, in large part due to the accumulation of macrophage white blood cells and promoted by low density lipoproteins without adequate removal of fats and cholesterol from the macrophages by functional high density lipoprot...
. This is very common in patients with diabetes mellitus
Diabetes mellitus

Diabetes mellitus , often referred to simply as diabetes , is a syndrome of disordered metabolism, usually due to a combination of genetic disorder and environmental causes, resulting in abnormally high blood sugar levels ....
, hypertension
Hypertension

Hypertension, also referred to as high blood pressure, HTN or HPN, is a medical condition in which the blood pressure is chronically elevated....
 or other chronic pathophysiological conditions. One of the main mechanisms of endothelial dysfunction is the diminishing of nitric oxide
Nitric oxide

Nitric oxide or nitrogen monoxide is a chemical compound with chemical formula NitrogenOxygen. This gas is an important signaling molecule in the body of mammals, including humans, and is an extremely important intermediate in the chemical industry....
, often due to high levels of asymmetric dimethylarginine
Asymmetric dimethylarginine

Asymmetric dimethylarginine is a naturally occurring chemical found in blood plasma. It is a metabolism by-product of continual protein modification processes in the cytoplasm of all human cells....
, which interfere with the normal L-arginine
Arginine

Arginine is an a-amino acid. The Optical isomerism is one of the 20 most common natural amino acids. Its codons are CGU, CGC, CGA, CGG, AGA, and AGG....
-stimulated nitric oxide synthesis
Nitric oxide synthase

Nitric oxide synthases are present among eukaryotic enzymes as dimeric, calmodulin-dependent or calmodulin-containing cytochrome p450-like hemoprotein that combine reductase and oxygenase catalytic domains in one dimer, bear both flavin adenine dinucleotide and flavin mononucleotide , and carry out a 5`-electron oxidation of non-aromatic a...
.

See also


  • Endothelium-derived relaxing factor
    Endothelium-derived relaxing factor

    Endothelium-derived relaxing factor is produced and released by the endothelium that results in smooth muscle relaxation. The most well characterized is nitric oxide, and some older sources consider the two terms to be equivalent....
     (EDRF)
  • Robert F. Furchgott
    Robert F. Furchgott

    Robert Francis Furchgott is a Nobel Prize-winning United States biochemist.Furchgott graduated with a degree in chemistry in 1937 from the University of North Carolina at Chapel Hill, received his Ph.D in biochemistry at Northwestern University in 1940....
     (1998 Nobel prize for discovery of EDRF)
  • VE-cadherin
    VE-cadherin

    Cadherin 5, type 2 or VE-cadherin also known as CD144 , is a type of cadherin. It is encoded by the human gene CDH5....
  • Caveolae
    Caveolae

    In biology, caveolae are small invaginations of the plasma membrane in many vertebrate cell types, especially in endothelium cells and adipocyte....
  • Weibel-Palade bodies
    Weibel-Palade body

    In physiology, Weibel-Palade bodies are organelles in the endothelial cells, the cells which make up the endothelium, the exceedingly thin cell sheet which lines all blood vessels, and the heart....
  • Endothelial microparticle
    Endothelial microparticle

    Endothelial microparticles are small vesicle s that are released from endothelium cell and can be found circulating in the blood. The microparticle consists of a plasma membrane surrounding a small amount of cytosol....
    s
  • Endothelial progenitor cells
    Endothelial progenitor cell

    Endothelial progenitor cells are bone marrow-derived cells that circulate in the blood and have the ability to differentiate into endothelial cells, the cells that make up the lining of blood vessels....
  • Endocardium
    Endocardium

    The endocardium is the innermost layer of tissue that lines the chambers of the heart. Its Cell , embryology and biology, are similar to the endothelium cells that line blood vessels....
  • Tunica intima
    Tunica intima

    The tunica intima is the innermost layer of an artery or vein. It is made up of one layer of endothelial cells and is supported by an internal elastic lamina....
  • Apelin
    Apelin

    Apelin is a recently identified endogenous ligand for the G-protein-coupled apelin receptor. It is widely expressed in various organs such as the heart, lung, kidney, adipose tissue, gastrointestinal tract, brain, adrenal glands, endothelium, and human blood plasma....
  • Susac's syndrome
    Susac's syndrome

    Susac's syndrome is a microangiopathy characterized by encephalopathy, branch retinal artery occlusions and hearing loss. It is caused by the immune system attacking healthy tissue, and can lead to mental disorders....


Bibliography

  • Molecular Biology of the CELL, 4th edition, Alberts et al., 2002


External links


- "Capillaries, non-fenestrated (EM, Low)"