26th June 2023

Physiology of the glomerulus

Glomerulonephritis is caused by inflammation of the glomerulus. The glomerulus is involved in ultrafiltration of the blood (filtration under pressure), regulating renal blood flow and maintenance of systemic blood pressure. The glomerulus is a bundle of capillaries contained within Bowman’s capsule, and together they make up the renal corpuscle. The renal corpuscle filters blood – this happens when blood travels from the afferent arteriole into the glomerulus under pressure. The fenestrated endothelial cells of the glomerular capillaries and podocytes allow water, ions, and small molecules from the bloodstream to flow into Bowman’s capsule and out into the proximal convoluted tubule to eventually be excreted in the urine. Larger molecules, such as proteins and blood cells, are normally unable to pass through the glomerulus and therefore remain within the blood.