Diuretic Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Diuretic and links to relevant pages within the course.
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| Identify the urine sediment element indicated by the arrow in the illustration: | View Page |
| Formation and Significance of Casts Casts are cylindrical bodies formed either in the distal convoluted tubules or the collecting ducts of the kidney. Since the walls of the tubule act as a mold for cast formation, the width of the tubule determines the width of the cast. Thus, narrow casts are formed in the distal tubules while broad casts are formed in the collecting ducts.
The matrix of all casts is thought to be Tamm-Horsfall protein, a glycoprotein secreted by the distal loop of Henle and the distal tubule. This protein entraps cells and granular material of tubular origin.
Very few casts are seen in the urine of a person without renal disease, except for hyaline casts, which may be transiently present after strenuous exercise, and during fever, diuretic therapy, and congestive heart failure.
A significant number of urinary casts usually indicates the presence of renal disease.
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| Hyaline Casts Hyaline casts are the type most commonly seen in the urine sediment. A few hyaline casts may occasionally be found in normal urine, and hyaline casts may be seen after strenuous exercise, during fever, diuretic therapy. Pathologically, hyaline casts may be seen with congestive heart failure, and may be seen together with other types of casts in a variety of renal diseases. Hyaline casts have a refractive index similar to the urine in which they are suspended. For this reason, hyaline casts will appear almost invisible under brightfield microscopy, but are easily of seen by phase-contrast microscopy. | View Page |
| Cuboidal Cells Increased numbers of cuboidal cells are found in renal transplant rejection, acute tubular necrosis (diuretic phase), injuries that interrupt blood flow to the kidney, and acute glomerulonephritis accompanied by tubular damage. Ingestion of various drugs and chemicals may cause significant tubular shedding of these epithelial cells. Cuboidal cells are easily seen in urine in cases of salicylate intoxication. | View Page |