Renal System Part 1 (Exam 4) Flashcards
The functional unit of the kidney is the _____
nephron
How many nephrons per kidney?
1 million
A nephron is composed of:
Glomerulus Proximal Tubule Loop of Henle Distal tubule Collecting duct
The proximal tubule absorbs large amount of?
H2O, Glucose, uric acid, Na, Cl, HCO3
Loop of Henle absorbs?
Na, Cl, H2O
Distal tubule controls excretion of?
Na, K, HCO3, H
Collecting duct regulates?
Amount of water in urine
What 3 labs are tests of renal function?
BUN Creatinine Urinalysis
What is BUN? What is its normal range?
Blood urea nitrogen 8-20mg/dl
BUN is a marker of?
Protein metabolism
Creatinine is a product of?
Skeletal muscle contraction
Daily production of Cr depends on?
Muscle mass
Normal range for Cr?
0.5-1.1
A doubling of Cr corresponds to a ___ decrease in renal function
50%
What two groups would you expect to see lower creatinine levels assuming no renal disease?
Females Spinal cord injuries
What is the most accurate test of glomerular filtration rate?
Inulin filtration rate
What test is ordered most often to for glomerular filtration rate?
CrCl (creatinine clearance)
Normal CrCl?
90-140ml/min
What tests are required to detect CrCl?
24 hour urine and serum creatinine drawn within 24 hours of urine collection
If your patient refuses a 24 hour urine, what can you use to estimate a CrCl?
Cockroft-Gault or MDRD equations
To calculate a Cockroft-Gault, what measurements do you need?
Age, weight, and serum Cr
To calculate an MDRD, what measurements are neccessary?
Age, sex, ethnicity, plasma Cr (PCr)
What is measured in a unrinalysis?
Specific gravity, pH, glucose, protein, ketones, blood, bilirubin, nitrite, and leukocyte esterase
Normal urine pH?
4.5-8
Alkalinic urine can be a sign of?
UTI or renal tubular defects
Normal specific gravity?
1.010-1.025
A high specific gravity can indicate _____, while a low specific gravity can indicate _____.
Concentrated (dehydration) Dilute (renal failure, over hydration)
What ion is the main contributor to specific gravity?
Na
Normal urine ketones measure as _____
negative
Name a few populations that may have ketonuria?
- Uncontrolled diabetics
- Ketoacidosis patients
- High protein diets
- Patients with excessive vomiting and dehydration
Urine glucose is normally negative unless plasma glucose is above ____
250-300
Suspect ______ ______ in a patient with proteinuria and edema
Nephrotic syndrome
Bilirubin and urobilinogen would be elevated in what conditions?
- Liver damage
- Obstruction of bile duct
Name 1 thing that could cause a false negative for blood in urine
High doses of Vit C
What S/S should make you think of bladder carcinoma?
Painless hematuria with history of smoking
When suspicious of a UTI, what value will likely detect presence of WBCs?
Leukocyte esterase
How does urine nitrate help in diagnosis of UTIs?
Bacteria produce nitrate reductase, which converts nitrate to nitrite.
What type of bacteria commonly produce reductase?
Gram negative organisms
A patient taking pyrimidine presents for UTI symptoms. Her UA is + for nitrite. Is this enough to diagnose a UTI?
No, the color of urine interferes with the nitrite test. Pyrimidine (Azo) is a drug that interferes with urine color.
Sterile pyruia should make you think of?
TB
UA with RBCs should make you think of?
Infection, renal calculi
UA with eosinophils should make you think of?
interstitial nephritis.
Urinary casts are formed in the _____
Distal and collecting tubules
Casts present after exercise or chronic renal failure?
Hyaline
Casts present during glomerulonephritis or SBE(subacute bacterial endocarditis??)?
Red cell casts
What casts would you expect to be present during pyelonephritis?
White cell casts
What cell casts would you expect to be present during tubular necrosis?
Epithelial cell casts
What cell casts would you expect to be present during nephrotic syndrome, lead toxicity, or glomerulonephritis?
Granular cell casts
What cell casts would you expect to be present during renal failure/acute tubular necrosis?
Waxy cell casts
Crystal in urine should make you suspicious for?
Stones
Name 1 thing that could cause a false positive for blood in urine
Myoglobin
