NPN Compounds and Kidney Function Tests Flashcards
2 regions of the kidney
renal cortex (outer), renal medulla (inner)
functional unit of kidney
nephron
stimulates bone marrow to produce RBCs
erythropoietin
bean shaped located on either side of
spinal column
main function of kidneys
urine formation and excretion of waste products
adrenal glands secretes
aldosterone & vasopressin
prevents water loss and is also known as
vasopressin, anti-diuretic hormone
regulates water and salt in the body
aldosterone
parts of nephrons
PCT, DCT, loop of henle, glomerulus, collecting duct
promotes reabsorption of sodium and excretion of potassium
aldosterone
function of PCT
reabsorbs Na, Cl, HCO3-, Glucose, Amino acids, Proteins, Urea, & Uric acid
function of collecting duct
final site for concentration or dilution of urine
function of loop henle
site of major exchange of water and salt
NPN Compounds %
urea - 45%
uric acid - 20%
creatine - 1-2%
amino acid - 20%
creatinine - 5%
ammonia - 0.2%
plasma contain _ of NPN compound
20-35 mg/dL
ammonia is detoxified in the _ to produce _
liver, urea
most abundant NPN
urea
ammonia exist as _ in normal blood pH
ammonium ions
acute metabolic disorder of the liver & common in children
Reye’s syndrome
normal BUN-creatinine ratio
10:1 - 20:1
Major end product of protein and amino acid catabolism
BUN
Easily removed by dialysis
BUN
In BUN, approximately ____ of the nitrogen is excreted
80%
In BUN, Formed through the ______ in the liver
Krebs-Henseleit (Urea) cycle
Excreted by the kidneys – ___ reabsorbed
___ of the total are excreted through the gastrointestinal tract and skin.
40% , <10%
Clinical application of BUN measurement
- Evaluate renal function
- Assess dehydration status
- Determine the nitrogen balance in the body
- Aid in the diagnosis of renal disease
- Verify the efficacy of dialysis
In BUN, Concentration is determined by
- Renal function
- Dietary intake
- Protein catabolism rate
End (waste) product of muscle metabolism derived from creatine and creatine phosphate
creatinine
Creatine is converted to creatinine through_____
dehydration
Creatine phosphate is converted to creatinine through ____
dephosphorylation
Creatine is phosphorylated to creatine phosphate by the presence of _____
creatine kinase
Creatinine is synthesized primarily by the liver from ____
arginine, glycine and methionine
Partially secreted by the proximal tubules via the organic cation transport pathway
creatinine
Not easily removed by dialysis
creatinine
Not reabsorbed by the tubules
creatinine
Measure the completeness of 24 hour urine collection (urine creatinine).
creatinine
Index of overall renal function
creatinine
Elevated creatinine is found in ____
abnormal renal function
creatinine measurement
- Sufficiency of kidney function
- Severity of kidney damage
- Monitor progression of kidney disease
In Acute Kidney Injury, functional or structural abnormalities or markers of kidney damage (seen in blood, urine, tissue test, imaging studies) present for___
3 months
stage 1 creatinine
SCC = >0.3 mg/dL or 150-200%
UOC = <0.5 mL/kg for >6hr
Heating converts creatine to creatinine and the difference between the two samples is the _______.
creatine concentration
stage 2 creatinine
SCC = >200 - 300%
UOC = <0.5 mL/kg for >12hr
stage 3 creatinine
SCC = >300%, 4 mg/dL or acute increase of >0.5 mg/dL
UOC = <0.3 mL/kg for >24hr or anuria of >12hr
Specialized test, not part of routine testing
Creatine
In Creatine, Analyzing the sample for creatinine before and after heating in acid solution using an endpoint _____.
Jaffe method
Elevated in plasma and urine in
Muscular dystrophy, hyperthyroidism, trauma.
Increased concentration of BUN and Creatinine in the blood
Azotemia
elevated plasma urea concentration accompanied by renal failure
Uremia/Uremic syndrome
Reduced Renal Blood Flow
pre renal azotemia
Less blood delivered to the kidney
pre renal azotemia
Less Urea filtered
pre renal azotemia