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97 Cards in this Set

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What and where is the macula densa?
Group of densely packed cells of the distal tubular epithelium that act as chemoreceptors and feed information to the JGA, which is directly apposed.
What is the JGA?
Juxtaglomerular Apparatus, part of the afferent arteriole of the glomerulus that secretes renin in response to decreased blood pressure sensed by the kidney.
Besides the kidneys, what other structures are retroperitoneal at their level?
- parts of the duodenum
- part of the pancreas
- Aorta
- IVC
- ascending & descending colon
- adrenal glands
- rectum
The ureters pass under/over the uterine artery, and under/over the vas deferens.
under; under
For a 100 kg man, how many liters of total body water does he have?
60 L (60% of total body wt.)
For a 100 kg man, what is the volume of intracellular fluid he has?
40 L (40% of total body wt.)
For a 100 kg man, what is the volume of extracellular fluid he has?
20 L (20% of total body wt.)
For a 100 kg man, what is the volume of plasma in his body?
5 L (5% of total body wt.)
What percent of your total body weight is interstitial volume?
15%
What do you use to measure extracellular fluid volume?
inulin - a polysaccharide
What do you use to measure plasma volume?
radiolabelled albumin
What is the formula for renal clearance of a substance?
C = (U*V)/P where U is urine concentration of substance, V is urine flow rate, and P is plasma concentration of substance.
If clearance is < GFR:
there is net reabsorption of substance
If clearance = GFR:
there is no net reabsorption or secretion of substance
If clearance > GFR:
there is net secretion of substance
What 3 things make up the glomerular filtration barrier?
1) fenestrated capillaries (size barrier)
2) heparan sulfate (- charge barrier)
3) podocyte foot processes
What is lost in nephrotic syndrome and what does that lead to?
charge barrier (and podocyte foot processes) - albuminuria, hypoproteinemia, hyperlipidemia, generalized edema
GFR is calculated by using clearance of:
inulin - freely filtered, neither reabsorbed nor secreted by kidneys
How can you calculate GFR using hydrostatic pressures and oncotic pressures?
Kf * [(Pgc - Pbs) - (Onc gc - Onc bs)], where gc = glomerular capillary and bs = bowman's space
What is PAH used for?
Clearance of para-aminohippuric acid is used to estimate Effective Renal Plasma Flow, because it is filtered and actively secreted by the kidney. True Renal Plasma Flow is 10% greater than this estimate, however.
What is "clearance?"
VOLUME of plasma from which a substance is cleared completely per unit time
How do you calculate Renal Blood Flow?
RBF = RPF/(1-Hct)
Prostaglandins preferentially ___ the afferent arteriole. Your RPF ___, GFR ___, so filtration fraction ___.
dilate; increases, increases, remains constant
Filtration Fraction =
GFR/RPF
AII preferentially ___ the efferent arteriole. Your RPF ___, GFR ___, so filtration fraction ___.
vasoconstricts; decreases, increases, increases
How does constricting the ureter affect RPF, GFR, and FF?
no change; decrease, decrease
At what level of plasma glucose does glucosuria begin?
200 mg/dL
At what plasma level of glucose is the glucose transport mechanism saturated?
350 mg/dL
What happens in the proximal convoluted tubule?
Reabsorb most of bicarb, glucose, AA, Na, water. Secrete ammonia which acts as buffer for secreted protons.
What happens in the thin descending limb?
Passive reabsorption of water. Is impermeable to Na+.
What happens in the thick ascending limb?
Active reabsorption of Na/K/Cl via NKCC cotransporter. Indirect reabsorption of calcium & magnesium. Is impermeable to water.
What happens in the distal convoluted tubule?
Active reabsorption of NaCl via Na/Cl cotransporter. PTH acts here to reabsorb calcium.
What happens in the collecting tubules?
Aldo acts to reabsorb Na+ in exchange for K+ and H+ secretion. ADH acts to reabsorb water.
What are 4 functions of AII?
1) vasoconstriction
2) aldo release from zona glomerulosa of adrenals
3) ADH release from posterior pituitary
4) stimulate hypothalamus (supraoptic nucleus) --> thirst --> drink water
What does renin do? What stimulates its release?
Released by JG cells in response to low BP & low Na+ delivery to distal tubule & increased sympathetics, and cleaves angiotensinogen to AI, which is then cleaved by ACE to AII.
How does the kidney respond to hypoxia?
Endothelial cells of peritubular capillaries make EPO.
What does the kidney have to do with calcium?
Has enzyme 1-a-hydroxylase to make 1,25(OH)2 vitamin D for gut calcium absorption. Enzyme is activated by PTH.
What does the kidney make to vasodilate the afferent arterioles?
PG's - vasodilate afferent to increase GFR
How can NSAIDs cause acute renal failure?
If someone is in a vasoconstrictive state, the inhibiton of PG synthesis by NSAIDs can cause vasoconstriction of afferent arteriole and a drop in GFR.
How do you calculate pH if given the pKa, [HCO3], and PCO2?
Henderson-Hasselbach equation:
pH = pKa + log([HCO3]/0.03*PCO2)
A patient comes in with a blood pH of 7.2. His PCO2 > 40mmHg. What could possibly be wrong with this man?
Respiratory acidosis, caused by hypoventilation. Could be airway obstruction, lung disease, opioid overdose, weak respiratory muscles.
A patient comes in with a blood pH of 7.2 and a PCO2 < 40mmHg. What do you want to know next?
He is in metabolic acidosis with respiratory compensation. You want to know if there is an increased anion gap to narrow down DDx.
What are causes of metabolic acidosis with increased anion gap?
M- methanol
U- uremia
D- diabetic ketoacidosis
P- paraldehyde, phenformin
I- iron, INH
L- lactic acidosis
E- ethylene glycol
S- salicylates
What are causes of metabolic acidosis with normal anion gap?
diarrhea, glue sniffing, RTA, hyperchloremia
Someone hyperventilating will end up in respiratory/metabolic acidosis/alkalosis.
respiratory alkalosis (pH > 7.4 with PCO2 < 40mmHg)
What can cause metabolic alkalosis? What is the blood pH and PCO2 profile with respiratory compensation?
pH > 7.4; PCO2 > 40
vomiting, diuretics, antacid, hyperaldosteronism
How do you calculate if the PCO2 is compensated for in metabolic acidosis?
Winter's formula:
PCO2 = 1.5(HCO3) + 8 (+/- 2)
Metabolic alkalosis compensation: PCO2 increases ___ for every 1 mEq/L increase in bicarb
0.7
Acute respiratory acidosis compensation:
increase 1:10 (bicarb:PCO2)
Chronic respiratory acidosis compensation:
increase 3.5:10 (bicarb:PCO2)
Acute respiratory alkalosis compensation:
decrease 2:10 (bicarb:PCO2)
Chronic respiratory alkalosis compensation:
decrease 5:10 (bicarb:PCO2)
What is Potter's Syndrome?
bilateral renal agenesis (malformation of ureteric limb bud) --> oligohydramnios --> limb deform, face deform, pulmonary hypoplasia
RBC casts in urine =
glomerular inflammation (nephritic syndrome), malignant HTN, ischemia
WBC casts in urine =
tubulointerstitial disease, acute pyelonephritis, glomerular disorders
Granular casts =
acute tubular necrosis!
Waxy casts =
chronic renal failure
Bladder cancer --> see ___
RBCs
Acute cystitis --> see ___
WBCs
Describe 4 features of nephritic syndrome:
1) hematuria
2) HTN
3) azotemia
4) oliguria
Name the 6 conditions that give you nephritic syndrome:
1) acute post-streptococcal
2) rapidly progressive (crescentic)
3) Goodpasture's
4) Membranoproliferative
5) IgA (Berger's)
6) Alport's syndrome
Nephrotic syndrome is characterized by:
1) proteinuria
2) hypoalbuminemia
3) hyperlipidemia
4) peripheral/periorbital edema
Name 5 nephrotic syndromes:
1) membranous
2) focal segmental glomerular sclerosis
3) minimal change disease
4) diabetic nephropathy
5) SLE membranous glomerulonephritis
What can renal cell CA's secrete?
1) EPO
2) ACTH
3) PTH
4) prolactin
How does renal cell CA present?
hematuria, flank pain, fever, wt. loss, palpable mass, secondary polycythemia
What 2 things increase risk of renal cell CA?
smoking, obesity
Who most often gets renal cell CA?
men 50-70 yrs, also associated with von Hippel-Lindau (VHL gene deletion ch3; recall hemangioblastomas of retina/cerebellum/medulla)
Ammonium magnesium phosphate kidney stones are caused by:
urease positive organisms (Proteus, Staph, Klebsiella)
What is the most common kidney stone?
calcium oxalate or phosphate, from hypercalcemia
Under what conditions do you often see uric acid kidney stone?
hyperuricemia (gout, leukemia, myeloproliferative disorders)
Tell me about Wilm's tumor:
- mostly early childhood tumor
- deletion WT1 gene on ch11
- huge flank mass
- WAGR: Wilm's tumor, aniridia, genitourinary malformation, mental-motor retardation
Painless hematuria with RBCs in urine suggest:
bladder cancer (transitional cell CA)
Where else can you see transitional cell CA besides bladder?
renal calyces, renal pelvis, ureters
Transitional cell CA is associated with: (4)
- phenacetin (analgesic)
- smoking
- aniline dyes
- cyclophosphamide (hemorrhagic cystitis, used for NHL, breast & ovarian CA)
Fever, costovertebral angle tenderness, WBC casts, neutrophil infiltrate with abscesses in renal interstitium =
acute pyelonephritis
Lymphocyte infiltrate, fibrosis, eosinophilic casts in renal tubules =
chronic pyelonephritis
What is it called when there is acute general infarction of the cortices of both kidneys? What can cause this?
Diffuse cortical necrosis: vasospasm, DIC, obstetric catastrophes, septic shock
Renal ischemia, crush injury, toxins, can all lead to ___ ___ ___ which is the most common cause of acute renal failure.
acute tubular necrosis
Renal papillary necrosis is associated with: (3)
1) diabetes mellitus
2) chronic phenacetin use
3) acute pyelonephritis
What is the definition of acute renal failure?
decline in renal function w/increase in BUN and creatinine over a period of several days
What can cause post-renal acute renal failure?
bilateral outflow obstruction: stones, BPH, neoplasia
What are causes of intrinsic acute renal failure?
acute tubular necrosis, ischemia, toxins
What are causes of pre-renal acute renal failure?
hypotension --> decreased RBF
A patient comes in with urine osmolality > 500. Which type of acute renal failure does he have?
pre-renal acute renal failure
What are consequences of renal failure?
1) anemia
2) hyperkalemia
3) metabolic acidosis
4) renal osteodystrophy
5) uremic encephalopathy
6) HTN
7) chronic pyelonephritis
Too much serum Na -->
irritability, delirium, coma
Not enough serum Na -->
disorientation, stupor, coma
Too much serum Cl, secondary to:
secondary to metabolic acidosis (with normal anion gap)
Not enough serum Cl, secondary to:
secondary to metabolic alkalosis
Too much serum K -->
peaked T waves, arrhythmias
Not enough serum K -->
U waves, flattened T waves, arrhythmias, paralysis
Not enough calcium -->
tetany, neuromuscular irritability
Too much calcium -->
ab pain, delirium, renal stones
Not enough magnesium -->
neuromuscular irritability, arrhythmias
Too much magnesium -->
delirium, dec. DTRs, cardiopulmonary arrest
Not enough phosphate -->
bone loss
Too much phosphate -->
metastatic calcification, renal stones