Bowman's capsule or the Bowman capsulecapsula glomerulior glomerular capsule is a cup-like sac at the beginning of the tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine. A glomerulus is enclosed in the sac.
Fluids from blood in the glomerulus are collected in the Bowman's capsule. Inside the capsule, the layers are as follows, from outside to inside: [ citation needed ]. Any proteins under roughly 30 kilodaltons can pass freely through the membrane, although there is some extra hindrance for negatively charged molecules due to the negative charge of the basement membrane and the podocytes.
Any small molecules such as waterglucosesalt NaClamino acidsand urea pass freely into Bowman's space, but cellsplatelets and large proteins do not. As a result, the filtrate leaving the Bowman's capsule is very similar to blood plasma filtrate or glomerular filtrate is composed of blood plasma minus plasma protein i.
Measuring the glomerular filtration rate GFR is a diagnostic test of kidney function. A decreased GFR may be a sign of kidney failure. A number of diseases can result in various problems within the glomerulus. Examples include acute proliferative endocapillary glomerulonephritis, mesangioproliferative glomerulonephritis, mesangiocapillary membranoproliferative glomerulonephritis, acute crescentic glomerulonephritis, focal segmental glomerulonephritis, and diabetic glomerulosclerosis.
Bowman's capsule is named after Sir William Bowman —a British surgeon and anatomist. Alexander Schumlansky —in his doctoral thesis "De structura renum" "About Kidney Structure", in Latin ; thus, much prior to Bowman. Hälsofrågor with the glomerulus it is known as a renal corpuscleor a Malpighian corpuscle, named after Marcello Malpighi —an Italian physician and biologist.
This name is not used widely anymore, probably to avoid confusion with Malpighian bodies of the spleen. Contents move to sidebar hide. Article Talk. Read Edit View history. Tools Tools. Download as PDF Printable version. Kidney structure which performs the first step in blood filtration.
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Oxford University Press. ISBN Journal of the American Society of Nephrology.