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15 Cards in this Set
- Front
- Back
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Each human kidney has app. 1.3 million nephrons. TRUE/FALSE
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TRUE.
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How is the glomerulus formed?
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It is about 200um in diameter, and formed by the invagination of a tuft of capillaries into the dilated, blind end of the nephron(Bowman's capsule).
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What separates the blood from the glomerular filtrate?
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Two cellular layers separate the blood from the glomerular filtrate in Bowmans capsule; the capillary endothelium and the specialized epithelium of the capsule.
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The specialized epithelium of the capsule, is made up of....
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podocytes, overlying the glomerular capillaries.
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The capillary endothelium and the specialized epithelium of the capsule are separated by what?
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They are separated by a basal lamina. Stellate cells are located between the basal lamina and the endothelium.
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Stellate cells are also called.....
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mesangial cells.
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These mesangial cells are similar to cells called pericytes, which are found in the walls of the capillaries elsewhere in the body. TRUE/FALSE
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TRUE.
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Mesangial cells are very common between....
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two neighboring capillaries.
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What are mesangial cells?
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They are contractile cells and play a role in the regulation of glomerular filtration. They also secrete various substances, take up immune complexes, and are involved in the production of glomerular disease.
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How can one describe the endothelium of glomerular capillaries?
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IT is fenestrated, with pores that are 70-90 nm in diameter. The cells of the epithelium(podocytes) have pseudopodia that interdigitate to form filtration slits along the capillary wall. These slits are app. 25nm wide.
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The glomerular membrane permits the free passage of neutral substances up to _____ in diameter, and almost totally excludes those with diameters of ________.
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4nm/8nm. The charges on molecules as well as their diameters affect their passages into Bowmans capsule.
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The human proximal convoluted tubule is about_____mm long and _____um in diameter.
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15mm/55um in diameter.
The luminal edges of the cells have a striate brush border due to the presence of innumerable 1X 0.7 um microvilli. |
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The nephrons with glomeruli in the outer portions of the renal cortex have short loops of henle(cortical), whereas those with glomeruli in the juxtamedullary region of the cortex (juxtamedullary nephrons) have long loops extending down into the medullary pyramids. TRUE/FALSE
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TRUE. In humans, only 15% of the nephrons have long loops.
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Where is the macula densa found?
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The thick end of the ascending limb of the loop of Henle reaches the glomerulus of the nephron from which the tubule arose and nestles between its afferent and efferent arterioles. Specialized cells at the end form the macula densa, which is close to the efferent and afferent arteriole.
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What is the juxtaglomerular apparatus?
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The macula, neighboring lacis cells and the renin secreting juxtaglomerular cells in the afferent arteriole form the JGA.
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