Jump to: navigation, search
Distribution of bloodvessels in cortex of kidney.
Latin glomerulus renis
Gray's subject #253 1221
Precursor Metanephric blastema
MeSH Kidney+Glomerulus
Dorlands/Elsevier g_07/12394744

WikiDoc Resources for Glomerulus


Most recent articles on Glomerulus

Most cited articles on Glomerulus

Review articles on Glomerulus

Articles on Glomerulus in N Eng J Med, Lancet, BMJ


Powerpoint slides on Glomerulus

Images of Glomerulus

Photos of Glomerulus

Podcasts & MP3s on Glomerulus

Videos on Glomerulus

Evidence Based Medicine

Cochrane Collaboration on Glomerulus

Bandolier on Glomerulus

TRIP on Glomerulus

Clinical Trials

Ongoing Trials on Glomerulus at Clinical

Trial results on Glomerulus

Clinical Trials on Glomerulus at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Glomerulus

NICE Guidance on Glomerulus


FDA on Glomerulus

CDC on Glomerulus


Books on Glomerulus


Glomerulus in the news

Be alerted to news on Glomerulus

News trends on Glomerulus


Blogs on Glomerulus


Definitions of Glomerulus

Patient Resources / Community

Patient resources on Glomerulus

Discussion groups on Glomerulus

Patient Handouts on Glomerulus

Directions to Hospitals Treating Glomerulus

Risk calculators and risk factors for Glomerulus

Healthcare Provider Resources

Symptoms of Glomerulus

Causes & Risk Factors for Glomerulus

Diagnostic studies for Glomerulus

Treatment of Glomerulus

Continuing Medical Education (CME)

CME Programs on Glomerulus


Glomerulus en Espanol

Glomerulus en Francais


Glomerulus in the Marketplace

Patents on Glomerulus

Experimental / Informatics

List of terms related to Glomerulus




A glomerulus is a capillary tuft surrounded by Bowman's capsule in nephrons of the vertebrate kidney. It receives its blood supply from an afferent arteriole of the renal circulation. Unlike most other capillary beds, the glomerulus drains into an efferent arteriole rather than a venule. The resistance of the arterioles results in high pressure in the glomerulus aiding the process of ultrafiltration where fluids and soluble materials in the blood are forced out of the capillaries and into Bowman's capsule.

A glomerulus and its surrounding Bowman's capsule constitute a renal corpuscle, the basic filtration unit of the kidney. The rate at which blood is filtered through all of the glomeruli is the glomerular filtration rate (GFR), measurements of which are often used to determine renal function.

Afferent circulation

The afferent arteriole that supplies the glomerulus is a branch off of an interlobular artery in the cortex.


If a substance can pass through the endothelial cells, glomerular basement membrane, and podocytes, then it is known as ultrafiltrate, and it enters proximal tubule. Otherwise, it returns through the efferent circulation, discussed below.

Endothelial cells

The endothelial cells of the glomerulus contain numerous pores (fenestrae) that, unlike those of other fenestrated capillaries, are not spanned by diaphragms. The cells have openings which are so large that nearly anything smaller than a red blood cell passes through that layer.


Glomerular basement membrane

The glomerular endothelium sits on a very thick (100-200 nm) glomerular basement membrane. It is not only uncharacteristically thick compared to most other basement membranes (40-50 nm), but it is also rich in negatively charged glycosaminoglycans such as heparan sulfate.

The negatively-charged basement membrane repels negatively-charged proteins from the blood, helping to prevent their passage into Bowman's space.


Podocytes line the other side of the glomerular basement membrane and form part of the lining of Bowman's space. Podocytes form a tight interdigitating network of foot processes (pedicels) that control the filtration of proteins from the capillary lumen into Bowman's space.

The space between adjacent podocyte foot processes is spanned by a slit diaphragm formed by several proteins including podocin and nephrin. In addition, foot processes have a negatively-charged coat (glycocalyx) that limits the filtration of negatively-charged molecules, such as serum albumin.

The podocytes are sometimes considered the "visceral layer of Bowman's capsule", rather than part of the glomerulus.

Intraglomerular mesangial cell

Intraglomerular mesangial cells are found in the interstitium between endothelial cells of the glomerulus. They are not part of the filtration barrier but are specialized pericytes that participate indirectly in filtration.

Efferent circulation

Blood is carried out of the glomerulus by an efferent arteriole instead of a venule, as is observed in most other capillary systems. This provides tighter control over the bloodflow through the glomerulus, since arterioles can be dilated and constricted more readily than venules, owing to arterioles' larger smooth muscle layer (tunica media).

Efferent arterioles of juxtamedullary nephrons (ie, the 15% of nephrons closest to the medulla) send straight capillary branches that deliver isotonic blood to the renal medulla. Along with the loop of Henle, these vasa recta play a crucial role in the establishment of the nephron's countercurrent exchange system.

The efferent arteriole, into which the glomerulus delivers blood, empties into an interlobular vein.

Juxtaglomerular cells

The walls of the afferent arteriole contain specialized smooth muscle cells that synthesize renin. These juxtaglomerular cells play a major role in the renin-angiotensin system, which helps regulate blood volume and pressure.

Additional images

External links

it:Glomerulo nl:Glomerulus