Renal Definitions

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Renal Definitions
2011-10-27 18:03:33

Anatomy and Physiology of Renal
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  1. Afferent Arteriole
    • Small branch of interlobular renal artery, enters glomerulus on vascular pole.
    • Brings arteriole into glomerulus.
    • Branches into glomerular capillaries that form the efferent arteriole.
    • Contains juxtaglomerular cells.
  2. Blood Supply
    • Kidneys recieve 20-25% of CO
    • 90% arterial blood stays in cortex
    • 9% enters outer medulla
    • 1% reaches the inner medulla.
    • Kidney maintains constant blood flow by autoregulation that functions when perfusion pressure is 60-180 mmhg
  3. Glomerular Basement Membrane (GBM)
    • Selectively permeable specialized vascular basement membrane outlining glomerular capillaries.
    • Regulates ultrafiltration of plasma and formation of primary urinary filtrate.
    • With fenestrated endothelial cells and foot processes forming epithelial cells (podocytes).
    • GBM forms glomerular capillary wall
  4. Glomerular filtration rate (GFR)
    • Rate at which the plasma is filtered in glomeruli, forming GUF.
    • Renal plasma flow=600 ml/min and the ratio of renal plasma flow to GFR is constant at 5:1
    • GFR ~120 ml/min
  5. Glomerulus
    • Initial portion of nephron between afferent and efferent arterioles on one side and the proximal convoluted tubule on other.
    • Made of fenestrated capillaries enclosed by Bowman's capsule
  6. Juxtaglomerular Apparatus
    • Structure composed of specialized renin secreting cells localized in wall of afferent arteriole in glomerulus.
    • Cells of macula densa a specialized part of distal convoluted tubule.
  7. Kidneys
    • Paired organs in retroperitoneum
    • Cortex outer part, medulla inner part.
    • Main function=formation of urine and elimination of superfluous water and minerals, met. waste products, drugs.
    • Secrete=hormones, growth factors, renin and epo
  8. Mesangium
    • Connective tissue framework of glomerulus into glomerular tuft from vascular pole.
    • Consists of mesangial cells and nonfibrillar ECM that fills space delimited by confluence of 3-4 glomerular capillaries.
  9. Nephron
    • Basic functional unit comprising of glomerulus, PCT, loop of Henle, distal tubule, collecting ducts.
    • connected to arterial blood supply and excretory urinary ducts.
    • 2 types: cortical nephrons and juxtamedullary nephrons.
  10. Cortical Nephrons
    • Short loops of henle
    • surrouned by capillary networks
  11. Juxtamedullary nephrons
    • long loops of henle extending into medulla.
    • surrounded by vasa recta.
  12. Renal arteries
    • There are two which originate from the abdominal aorta.
    • Kidneys, they branch forming large interlobar arteries.
    • give rise to arcuate arteries running along the corticomedullary junction.
    • arcuate arteries give rise to cortical interlobar arteries, which give rise to afferent arterioles.
    • Efferent arteriole leaving gives rise to peritubular capillaries and vasa rectus.
  13. Vasa Recta
    drain into small renal veins.
  14. Renin
    • Enzyme secreted by juxtaglomerular cells in response to reduced blood supply to kidney.
    • acts on angiotensinogen, transforming to angiotensin, stimulating aldosterone production in adrenal cortex.
    • Mechanism: renin raises the BP
  15. Ureter
    Tubular organ serves as path for urine from renal pelvis to urinary bladder.
  16. Urethra
    • Tubular organ serving as final path for fluid leaving urinary bladder during urination.
    • Males: passageway for semen.
  17. Urinary Bladder
    Hollow organ whose primary function is to store urine prior to urination.
  18. Urine
    • Fluid formed in kidney from ultrafiltered plasma, containing in addition to water, minerals, organic waste material.
    • Urine formed from nephron through a stepwise process that includes ultrafiltration of plasma, selective and site-specific reabsorption of minerals and water, secretion of other.
  19. Urothelium (Transitional epithelium)
    Specialized epithelium lining the renal calices, pelvis, ureters, urinary bladder, and posterior part of urethra.
  20. Vitamin D
    • Lipid-soluble vitamin hydroxylated in liver and after, the kidney.
    • Active form of vitaimin, 1,25 formed.
    • Regulates absorption and metabolism of calcium along with Parathyroid hormone.
  21. Anuria
    • Absence of urine (<100 ml urine/day)
    • Anuria is sign of renal failure and may be prerenal, intrarenal, postrenal.
  22. Prerenal
    Due to reduced renal perfusion in heart failure.
  23. Intrarenal
    Due to glomerulonephritis or toxic tubular necrosis
  24. Postrenal
    Due to obstruction of ureters or bladder outflow tract.
  25. Azotemia
    • increased blood concentration of N2-containing compounds (urea/creatinine).
    • [blood] of urea is conventionally expressed as BUN.
    • Sign of renal railure.
  26. Glycosuria
    • Appearance of glucose in urine in excess of minimal amounts normally found in urine
    • (<200 mg/24 hrs)
    • Consequence of hyperglycemia
    • Diatbetes mellitus
  27. Hematuria
    • Blood in urine
    • Macroscopic and visible to naked eye or microscopic and detectable only by microscopic examination of renal sediment.
  28. Lipiduria
    • Appearances of lipid droplets or lipid casts in urine.
    • Found in nephrotic syndrome and hyperlipemic states.
  29. Oliguria
    • Production of urine in small amounts.
    • Sign of renal failure, which may be prerenal, intrarenal, postrenal.
    • Adults: <400 ml/day
  30. Polyuria
    • Production of large quantities of urine.
    • Increased frequency of urination, and an abnormally large volume of luid excreted over a 24 hr period.
    • Adults: urine make exceeds 3-5 l/day
  31. Proteinuria
    • Excretion of proteins in urine in excess of the normal amount for the age of the patient.
    • Healthy: < 500 mg protein
    • Sign of glomerular injury and occurs in nephritic and nephrotic syndromes.
  32. Pyuria
    • Excretion of pus in urine.
    • Caused: bacterial infection
  33. Urinary Casts
    • Cylindrical structures found in urine, typically formed from protein-rich contents of the renal tubules.
    • Granular Casts