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Specific learning objectives. At the end of the class You must know.......... Step of formation of urine Filtration. Name the difference forcess in glomerular filration . Glomerular filtration rate and its normal value. Factor affecting to GFR. Mechanism of urine Formation.
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Specific learning objectives At the end of the class You must know.......... • Step of formation of urine • Filtration. • Name the difference forcess in glomerularfilration. • Glomerular filtration rate and its normal value. • Factor affecting to GFR.
Filtration –in Glomerulus • Selective Reabsorption • Selective Secretion • Excretion
1. Glomerular filtration refers to the movement of fluid and solutes from the glomerular capillaries into Bowman’s space.
2. Tubular reabsorption refers to the movement of materials from the filtrate in the tubules into the peritubular capillaries.
3.Tubular secretion refers to the secretion of solutes from the peritubular capillaries into the tubules.
Glomerular Membrane • Capillary endothelium of Glomerullar capillary • Basement membrane • Epithelial cells of Visceral layers of Bowman capsule • Mesangial cells
Glomerular Filtration rate (GFR)– • The total quantity of filtrate formed in all nephrons of both the kidneys in the given unit of time • Normal value :125ml/min or 180L/day
Formation of GFR • Passive process • Rateof filtration at any point along the capillary depends on the balance of different forces called as –Starling Forces
Driving forces for Glomerular filtration • Glomerular capillary pressure -60 mmHg • Reasons • Renal artery arise directly from abdominal aorta • The afferent arterioles are short, straight branches • The efferent arterioles have relatively high resistance
Opposing forces for Glomerular filtration • Glomerularcolloide osmotic pressure-32mmHg • Bowman’s capsule pressure-18mmHg
Factor Regulating GFR 1.Renal blood flow 2.Tubuloglomerular Feedback 3.Glomerular capillary pressure 4.Colloidal osmotic pressure 5.Hydrostatic pressure in Bowman capsule 6.Constriction of afferent arteriole 7.Constriction efferent arteriole 8.Surface area of capillary membrane 9.Permiability of capillary membrane 10.Sympathetic stimulation