Glomerular DiseasesMicroanatomy The nephron is the basic unit of the kidney, each kidney contain about one million nephron. The nephron consist of the glomerulus &the associated tubules that lead to the collecting duct . The Glomerulus : is a ball of capillaries surrounded by Bowman’s capsule. The glomerulus receive blood from afferent arteriole & is drained by the efferent arteriole.
nephronthe functional unit of the kidney•capable of forming urine•has two major components: glomerulus tubule: proximal loop of Henle distal collecting
The glomerulus contain 4 different types of cells: 1- Visceral epithelial cell( podocytes ). these cells have long projections from which foot processes arise & attach to the glomerular basement membrane ( make support to the GBM ) .2- Endothelial cells. these cells line the capillary lumen.
3- Mesangial cells: the mesangium provide a skeletal framwork to support the capillary loops & have contractile & phagocytic properties. due to it’s contractile capability, can control blood flow along the glomerular capillaries .4-Parietal epithelial cells: cover Bowman’s capsule .Glomerular Basement Membrane: prodused by fusion of the basement membrane of epithelial & endothelial cells .
Glomerular syndromes1- Nephrotic syndrome : Massive proteinuria ( > 3.5 gm/24hr. ) , with variable edema, hypoalbuminemia, hyperlipidemia & hyperlipiduria . A- NS with “bland” sediment : mean pure NS. B-NS with “active” sediment : mean “mixed” Nephrotic/nephritic syndrome . Normal proteinuria <150 mg /24 hr(<0.15gm/24 hr) .
5-Asymptomatic urinary abnormalities : - Isolated proteinuria (usually <2 gm/day ) - hematuria (with or without proteinuria ) .
Pathologic features of glomerulardisease Focal :mean affect some of glomeruli (but not all ). Diffuse : mean the lesion affect all glomeruli or >75% . Segmental : mean only a part of the glomerulus is affected by the lesion . Proliferative : abnormal proliferation of
Misangial :excessive production of misangial materials.Membranous :glomeruler basement is damaged &thickened .Membranoproliferative :causing both thickeningof glomerular basement membran &proliferation of mesangial cells . Crescent formation: epithelial cell proliferation& mononuclear cell infiltration in Bowman’s space.