Table of Contents
Definition of Glomerulus and Function
Glomerulus – the coiled capillary network within the nephron of the kidney through which blood passes for filtration. Glomeruli are abundant within the kidneys as each kidney contains more than a million nephrons.
The walls of the glomerulus are only a few cells in thickness. The glomerular walls are semipermeable, allowing smaller molecules such as water, metabolic wastes, glucose, and electrolytes to pass through and collect in the capsule (called Bowman’s capsule) that surrounds the glomerulus.
Together the glomerulus and Bowman’s capsule are the renal corpuscle. The fluid and its contents, called filtrate, passes into the tubules of the nephron, which further filter and concentrate the filtrate.
The nephron eventually reabsorbs 99 percent of the filtrate back into the blood; the remaining fluid drains into collecting ducts to move out of the kidneys as urine. The glomerular filtration rate (GFR) is an important measure of kidney function. The GFR of a healthy adult kidney is 125 milliliters per minute.
For further discussion of the glomerulus within the context of the urinary system’s structure and function please see the overview section “The Urinary System.”
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