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59 Cards in this Set
- Front
- Back
What is a nephron? |
The functional unit of the kidney, used for filtering the blood and composed of a glomerulus and tubule |
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What are the primary functions of the kidney? (6) |
Regulating blood volume, electrolyte balance, acid-base balance, excreting waste products, metabolism of Vitamin D, and production of erythropoeitin |
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What is the glomerulus? |
The site of filtration in the nephron, where fluid is filtered into Bowman's capsule |
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What are the tubules? |
The site of reabsorption and secretion in the nephron where everything except waste products is reuptaken |
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What ions are reabsorbed based on blood levels? |
K and Mg |
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What is aldosterone? |
A hormone which increases the kidneys' Na reabsorption |
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What is a GFR? |
A glomerular filtration rate-- measurement of the volume of fluid filtered through all glomeruli in one minute |
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What is an eGFR? |
An estimated glomerular filtration rate, based on equation |
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What factors impact the calculation of eGFR? |
Serum creatinine concentraion, age, and gender |
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What does a decrease in eGFR indicate? |
Impaired renal function |
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How is renal function tested? (6) |
GFRs/eGFRS, U&E tests (creatinine, urea, sodium, and potassium), acid-base balance, serum phosphates and calcium, vitamin D metabolism, urinary protein |
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What is creatinine? |
A waste product of muscle breakdown which is excreted in the urine |
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How effective of a renal function indicator is creatinine? |
Not especially-- not very sensitive to changes in renal function |
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What change in acid-base balance indicates renal failure? |
Acidosis |
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What ions can be measured to determine blood pH? |
H+, bicarbonate |
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How do serum phosphate levels indicate renal function? |
The kidney is involved in phosphate excretion so kidney damage leads to high PO4 levels |
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How do serum calcium levels indicate renal function? |
The kidney metabolises Vitamin D which affects calcium concentration |
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What effect does kidney failure have on calcium levels? |
Decreased levels |
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What effect does kidney failure have on phosphate levels? |
Elevated levels |
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What within the kidneys in renal failure causes low calcium? |
Increase in PO4 concentration, decrease in metabolism of Vitamin D |
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What causes protein to leak into tubules? |
Glomeruli damage |
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What causes proteinuria? |
Glomeruli damage |
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What molecule is the first to enter urine when glomeruli have been damaged? |
Albumin |
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What is acute renal failure? |
Decreased renal function which occurs over a number of hours or days |
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What are the causes of acute renal failure? |
Blood loss, dehydration, shock, glomerulonephritis, drugs, massive muscle breakdown, obstruction of renal flow |
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What products accumulate in acute renal failure? (5) |
Waste products (urea and creatinine), K+, PO4+, H+ |
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What does a decrease in GFR cause? |
A decrease in urine volume |
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What is the pH effect of acute renal function? |
Acidosis |
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What products decrease in concentration due to acute renal failure? |
Na+, Ca2+ |
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A patient presents with high creatinine and urea levels and is passing little urine after taking drugs. What is the most likely cause? |
Acute renal failure secondary to massive muscle tissue breakdown |
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What do high CK values indicate? |
Muscle tissue destruction |
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What is chronic renal failure / chronic kidney disease? |
The gradual decline of kidney function over many years |
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What causes chronic kidney disease? |
Diabetes, hypertension, diseases which affect nephrons |
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What happens to the GFR of someone with chronic kidney disease? |
Gradually decreases as damage becomes more severe |
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What biochemical changes occur in CKD? |
Similar to ARF but occur more slowly |
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Why are creatinine levels not good indicators of CKD? |
They only start to rise when 70% of kidney function has been lost |
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A patient presents with a low GFR, albuminuria, high creatinine and urea, as well as high glucose and HbA1c. What is the most likely cause? |
Poorly-managed diabetes causing chronic kidney disease |
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What electrolyte balance is coupled with water? |
Na+ |
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What two factors influence Na+ and H2O balance? |
Kidney function and hormones |
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Which hormones influence Na+ concentration? |
Adrenals like renin, angiotensin, and adosterone |
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Which hormones influence H2O concentration? |
Adrenals and ADH |
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What is ADH? |
Antidiuretic hormone, produced by the posterior pituitary, causing increased water reabsorption by the kidneys |
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What is hyponatremia? |
Low serum Na+ concentration |
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What are the effects of hyponatremia? |
Central nervous system malfunction |
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Why can hyponatremia cause CNS problems? |
If Na is low in ECF, H2O is constantly moving in and out of cells
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What causes hyponatremia? |
A loss of Na or an increase in H2O |
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What is hypernatremia? |
High serum Na+ concentration |
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What causes hypernatremia? |
Generally only due to loss of H2O |
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What are the effects of hypernatremia? |
Central nervous system malfunction |
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Why can hypernatremia cause CNS problems? |
If Na is high in ECF, H2O is constantly moving in and out of cells |
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What factors impact K+ levels? (3) |
Na + concentration, aldosterone, acid-base balance |
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What effect does acidosis have on serum K+ levels? |
Increased serum K+ |
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What effect does alkalosis have on serum K+ levels? |
Decreased serum K+ |
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What is hyperkalemia? |
High serum K+ concentration |
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What causes hyperkalemia? |
Hemolysis, cold weather, thrombocytosis |
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What effect does unbalanced potassium have on the heart? |
Causes arrythmias |
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What is hypokalemia? |
Low serum K+ concentration |
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What causes hypokalemia? |
Hot weather, decreased K+ intake or renal reabsorption, vomiting, diarrhea |
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What are the symptoms of hypokalemia? |
Arrhythmia, muscle weakness |