= Glomerular capsule
= Bowman's capsule
{c}
{synonym}
The <glomerular capsule>, or <Bowman's capsule>, is the cup-like epithelial structure surrounding the <glomerulus> in a <renal corpuscle>. Its outer wall and its visceral layer, formed by <podocytes>, enclose a <capsular space>. Fluid crossing the <glomerular filtration barrier> enters that space and then passes into the <proximal tubule>.<Kidneys by the National Cancer Institute>[nephron organization: glomerulus and surrounding epithelial capsule]{ref}
The space, its contents and its wall are distinct. In a section, identify the <capillary> tuft first, then the narrow receiving region around it, then the outer capsule. A <renal corpuscle> includes the tuft and capsule together; the capsule alone is not a second <glomerulus>. This observation prevents an anatomical label from being mistaken for an independent filtration unit.
The receiving compartment also matters mechanically. In a simplified filtration model, increasing <hydrostatic pressure> in the <capsular space> opposes fluid movement from the glomerular capillaries. Measuring only arterial pressure would therefore miss one side of the trans-barrier driving difference. Direct glomerular and tubular pressure measurements were an important part of the 1971 rat experiments establishing the physical basis of <glomerular filtration>.<The Dynamics of Glomerular Ultrafiltration in the Rat by Barry M. Brenner and others>[Abstract: direct capillary/tubular pressures and net filtration driving force]{ref}
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