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The glomerular basement membrane of the
JCI – New articles published
/ref> The glomerular membrane consists of
* Goodpasture's syndrome is also known as anti-glomerular basement membrane disease. Capillaries become inflamed as a result of damage to the basement membrane by
File:Renal corpuscle-en.svg, Renal corpuscle (glomerulus) showing glomular basement membrane.
"The GBM and its disorders" at dmed.ed.ac.uk
{{DEFAULTSORT:Glomerular Basement Membrane Kidney anatomy
kidney
In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...
is the basal lamina
The basal lamina is a layer of extracellular matrix secreted by the epithelial cells, on which the epithelium sits. It is often incorrectly referred to as the basement membrane, though it does constitute a portion of the basement membrane. The b ...
layer of the glomerulus. The glomerular endothelial cells
The endothelium (: endothelia) is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the res ...
, the glomerular basement membrane, and the filtration slits between the podocytes
Podocytes are cells in Bowman's capsule in the kidneys that wrap around capillaries of the glomerulus. Podocytes make up the epithelial lining of Bowman's capsule, the third layer through which filtration of blood takes place. Bowman's capsule ...
perform the filtration function of the glomerulus, separating the blood in the capillaries from the filtrate that forms in Bowman's capsule
Bowman's capsule (or the Bowman capsule, capsula glomeruli, or glomerular capsule) is a cup-like sac at the beginning of the Renal tubule, tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of b ...
. The glomerular basement membrane is a fusion of the endothelial cell and podocyte basal laminas, and is the main site of restriction of water flow. Glomerular basement membrane is secreted and maintained by podocyte cells.
Layers
The glomerular basement membrane contains three layers:/ref> The glomerular membrane consists of
mesangial cell
Mesangial cells are specialised cells in the kidney that make up the mesangium of the glomerulus. Together with the mesangial matrix, they form the vascular pole of the renal corpuscle. The mesangial cell population accounts for approximately ...
s, modified pericytes that in other parts of the body separate capillaries from each other. The podocytes adjoining them have filtration slits of diameter 25 nm that are formed by the pseudopodia arising from them. The filtration slits are covered by a diaphragm that includes the transmembrane protein nephrin.
Pathology
* Goodpasture's syndrome is also known as anti-glomerular basement membrane disease. Capillaries become inflamed as a result of damage to the basement membrane by antibodies
An antibody (Ab) or immunoglobulin (Ig) is a large, Y-shaped protein belonging to the immunoglobulin superfamily which is used by the immune system to identify and neutralize antigens such as bacteria and viruses, including those that caus ...
to alpha 3 NC1 domain of type IV collagen.
* Nephrotic syndrome
Nephrotic syndrome is a collection of symptoms due to kidney damage. This includes proteinuria, protein in the urine, hypoalbuminemia, low blood albumin levels, hyperlipidemia, high blood lipids, and significant edema, swelling. Other symptoms ...
is a change in the structure of the glomerular filtration mechanism usually in the glomerular basement membrane. Some symptoms include proteinuria, hypoalbuminaemia, oedema
Edema (American English), also spelled oedema (British English), and also known as fluid retention, swelling, dropsy and hydropsy, is the build-up of fluid in the body's tissue. Most commonly, the legs or arms are affected. Symptoms may inclu ...
, and hyperlipidemia
Hyperlipidemia is abnormally high levels of any or all lipids (e.g. fats, triglycerides, cholesterol, phospholipids) or lipoproteins in the blood. citing: and The term ''hyperlipidemia'' refers to the laboratory finding itself and is also use ...
.
* Diabetic glomerulosclerosis is a thickening of the basement membrane, which can become up to 4-5 times thicker than normal. Can be caused by insulin deficiency or resultant hyperglycemia
Hyperglycemia is a condition where unusually high amount of glucose is present in blood. It is defined as blood glucose level exceeding 6.9 mmol/L (125 mg/dL) after fasting for 8 hours or 10 mmol/L (180 mg/dL) 2 hours after eating.
Blood gluc ...
.
* Alport syndrome is a X-linked hereditary nephritis caused by mutations in type IV collagen, leading to a split lamina densa of the glomerular basement membrane. It also affects the eye and inner ear.
See also
* Agrin, a protein linked to heparan sulfate *basement membrane
The basement membrane, also known as base membrane, is a thin, pliable sheet-like type of extracellular matrix that provides cell and tissue support and acts as a platform for complex signalling. The basement membrane sits between epithelial tis ...
* nephrin
Additional images
References
External links
*"The GBM and its disorders" at dmed.ed.ac.uk
{{DEFAULTSORT:Glomerular Basement Membrane Kidney anatomy