16. Renal Flashcards
Crystal found in urine
Uric acid
2 functions of peritubular capillaries
Reabsorption and secretion
3 causes of proteinuria
- Renal disease
- Post-strenuous exercise
- Dehydration
Low MW proteins that are light chain Ig fragments
Bence Jones proteins
7 functions of kidney
- Urine formation
- Regulate fluid balance
- Regulate electrolyte balance
- Regulate acid/base balance
- Excrete waste products of metabolism
- Hormonal functions
- Protein conservation
Where is uromucoid produced
DCT, collecting duct
Cause of decreased serum uric acid
Fanconi’s disease
Acidic urine = formation of which calculi?
- Uric acid calculi
- Cystine calculi (rare)
What gets converted to urea? Where?
Protein -> aa -> ammonia -> urea
Liver
3 principle nitrogenous waste compounds
- Urea
- Creatinine
- Uric acid
When is uric acid soluble?
> pH 5.75 = sodium urate
Most common calculi
Calcium oxalate
Presence of waxy casts indicates?
End-stage renal disease
__________ rate of formation is constant per day and is proportional to one’s muscle mass
Creatinine
Cause of Type II RTA
Fanconi’s syndrome
Creatinine is made in the liver from these 3 compounds
- Arginine
- Glycine
- Methionine
Part of nephron that is permeable to ions (active and passive) but not to water
Ascending loop of Henle
Glomerular filtrate formation due to 2 things
- Pressure
- Selectivity by charge and size
Enzyme that catalyzes hydrolysis of urea to ammonia and CO2
Urease
Alkaline urine = formation of which calculi?
- Calcium phosphate
- Magnesium ammonium phosphate calculi (struvite)
Inborn error of metabolism associated w/ overproduction of uric acid resulting in arthritis, nephropathy, nephrolithiasis
Gout
Cause of type IV RTA
Diabetic nephropathy
Name of test that is starting to replace microalbumin
Albumin/creatinine ratio (ACR)
How to differentiate upper/lower UTI in terms of casts?
Lower - no casts
Upper - WBC casts
Pre-renal, renal- post-renal causes of increased serum BUN
Pre-renal = congestive heart failure, hemorrhage, dehydration, increased production in liver
Renal = kidney failure
Post-renal = urinary tract obstruction
Crystal found in pseudo-gout
Calcium pyrophosphate
4 hormones produced by kidneys
- Renin
- Vitamin D
- EPO
- Prostaglandins
ADH regulates final urine concentration by controlling?
Tubular permeability
Which renal tubular acidosis type? Basic urine pH
Type I (distal/classical RTA)
Part of nephron that is permeable to water by passive transport but not to ions
Descending loop of Henle
Effect of prostaglandins produced by kidneys?
Increase renal flow, sodium and water excretion, renin release
Formed when creatine loses a water molecule
Creatinine
Reabsorption of Na+ in DCT is under the control of?
Aldosterone
RBC casts indicates..?
Acute glomerulonephritis
Steps in production of creatinine
Creatine (liver) -> creatine phosphate via creatine kinase -> CP loses phosphoric acid and water => creatinine which diffuses into plasma
RI for creatinine clearance?
1.20 - 2.60 mL/sec/1.73m^2
High serum creatinine = ____ urine creatinine = _____ GFR
Low urine CR
Low GFR
Glomerular basement membrane cut-off size
68 kDa (size of albumin)
Countercurrent mechanism takes place in the?
Juxtaglomerular nephrons
Varying pH urine = formation of which calculi?
Calcium oxalate calculi
What to look for in Type I, II, and IV RTA?
I - renal STONES
II - BONE demineralization
IV - low ALDOSTERONE
Small amounts of urea can be excreted through these 2 places
GI
Skin
The selective reabsorption process in the loop of Henle is called the _______________ and serves to maintain the osmotic gradient of the medulla
countercurrent multiplier system
Constituent of hyaline casts
Uromucoid (Tamm-Horsfall mucoprotein)
Which renal tubular acidosis type? Acidic urine pH
Type IV (generalized distal RTA)
Formula for urine formation
Glomerular filtration - tubular reabsorption + tubular secretion = excretion/urine
What is oliguria
Diminished urine secretion in relation to fluid intake (<400 mL/day)
3 physiological functions of nephron
- Glomerular filtration
- Tubular reabsorption
- Tubular secretion
Crystal found in gout
Monosodium urate
Name of calculi that has multiple small calculi with varying size
Staghorn calculi
What form of uric acid causes urolithiasis and gout
pH <5.75
What is azotemia
Excess of urea/creatinine/other nitrogenous end products in blood
Type of nephron responsible for renal concentration
Juxtaglomerular
Function of aldosterone
Stimulates Na+ reabsorption, K+ and H+ secretion at DCT
Hormone that stimulates water reabsorption in DCT
ADH (DCT normally impermeable to water but ADH makes it permeable)
Where and what controls the production of aldosterone
Adrenal cortex
RAAS - decreased blood flow/BP in renal arteriole or decreased blood Na+
An increase in urea and BUN
Uremia
Which renal tubular acidosis type? Variable to <5.3 urine pH
Type II (proximal RTA)
What is another word for uremia
Azotemia
Word for complete suppression of urine formation and excretion (acute renal failure) <100 mL/day
Anuria
Cause of type I RTA
- Drugs
- Autoimmune
Enzyme that produces creatine when creatine phosphate loses a phosphoric acid
Creatinase
Waste product of purine metabolism
Uric acid
After kidneys, blood returns to venous system via _________ to the ________
via RENAL VEIN to the IVC
What is polyuria
Excessive excretion of urine (e.g. DM) >3 L/day
3 hormones that control tubular reabsorption
- ADH/vasopressin
- Aldosterone
- PTH
3 mechanisms of pathologic proteinuria
- Glomerular defect
- Tubular defects
- Overflow proteinuria
Renin secreted by nephron in response to..?
Low systemic BP
May interfere with creatinine measurements
- Bilirubin
- Ammonia
