Capsular epithelium Capsular space Pedicels RBC Filtration slits Dense layer

Capsular epithelium capsular space pedicels rbc

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Capsular epithelium Capsular space Pedicels RBC Filtration slits Dense layer Capillary endothelial cell Mesangial cell Pores Podocyte Nucleus 29
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R ENAL T UBULE Segments of the Renal Tubule Located in cortex Proximal convoluted tubule (PCT) Distal convoluted tubule (DCT) Separated by nephron loop (loop of Henle) U-shaped tube Extends partially into medulla 30
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F IGURE 26-6 T HE F UNCTIONAL A NATOMY OF A R EPRESENTATIVE N EPHRON AND THE C OLLECTING S YSTEM NEPHRON Distal convoluted tubule Proximal convoluted tubule Renal corpuscle Nephron loop KEY • Secretion of ions, acids, drugs, toxins • Variable reabsorption of water, sodium ions, and calcium ions (under hormonal control) Reabsorption of water, ions, and all organic nutrients Renal tubule Capsular space Glomerulus Efferent arteriole Afferent arteriole Glomerular capsule Production of filtrate Descending limb of loop begins Thin descending limb Ascending limb of loop ends Thick ascending limb Descending limb Ascending limb Further reabsorption of water (descending limb) and both sodium and chloride ions (ascending limb) Filtrate Water reabsorption Variable water reabsorption Solute reabsorption or secretion Variable solute reabsorption or secretion 31
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P ROXIMAL C ONVOLUTED T UBULE Arises from Bowman’s capsule. Simple cuboidal epithelium with prominent microvilli (a brush border). The brush border greatly increases the surface area here, because the majority of absorption occurs here. Freeze fractured view of the brush border of the PCT. This anatomical feature greatly increases the surface area. 32
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L OOP OF H ENLE Long U-shaped portion of the tubule that is mostly found in the medulla. It begins where the PCT straightens out and dips toward the medulla. Descending thick limb: simple cuboidal epithelium Descending thin limb: simple squamous epithelium Ascending thin limb: simple squamous epithelium Ascending thick limb: simple cuboidal epithelium 33
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D ISTAL C ONVOLUTED T UBULE Begins when the ascending limb reenters the cortex. Shorter and less coiled than PCT. Simple cuboidal with NO microvilli. 34
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