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169 Cards in this Set
- Front
- Back
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What is total body water volume?
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60% body weight or about 42L
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What is ECF volume?
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1/3 TBW or about 14L
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What is ICF volume?
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2/3 TBW or about 28L
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What separates the interstitial fluid from the plasma?
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capillary endothelium
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What is the interstitial fluid volume?
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4/5 ECF or about 11L
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What is plasma volume?
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1/5 ECF or about 3L
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Where does fluid accumulate with edema?
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interstitial fluid
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What is the volume of transcellular fluid?
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about 1.5L
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What are the 3 markers for TBW?
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T2O, D2O, antipyrine
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What are the 3 markers for ECF?
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inulin, mannitol, Na+
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What are the 3 markers for plasma?
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I-125 albumin, Cr-51 erythrocytes, Evans blue
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How do you calculate ICF?
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TBW-ECF
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How do you calculate interstitial volume?
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ECF-plasma volume
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How do you calculate volume of distribution (V2)?
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(V1 x C1)/C2
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When do all cells in the body have the same osmolality?
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at equilibrium
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What does osmolality depend on?
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number of particles, NOT their size
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What does water or D5W do to cells' volume and osmolality?
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volume inc and osmolality dec
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What does water or D5W do to ECF volume and osmolality?
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volume inc and osmolality dec
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What does isotonic saline or lactated ringers do to ECF volume and osmolality?
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volume inc and no change in osmolality
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What does isotonic saline or lactated ringers do to cells volume and osmolality? Why?
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no change in either; no osmotic gradient, so no water flux
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What does hypertonic saline do to ECF volume and osmolality?
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inc both
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What does hypertonic saline do to cells' volume and osmolality
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volume dec and osmolality inc
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What does sweating w/o fluid replacement do to ECF volume and osmolality?
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volume dec and osmolality inc
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What does sweating w/o fluid replacement do to cells' volume and osmolality?
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volume dec and osmolality inc
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What 3 things is capillary endothelium permeable to?
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water, ions, and small molecules
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Is capillary endothelium permeable to plasma proteins?
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minimally
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Where does plasma protein remain? What pressure does this exert?
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in vascular bed; osmotic pressure
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Capillary BP tends to cause fluid to move from?
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plasma to interstitial fluid
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What do you call a pathological increase in interstitial volume?
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edema
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What does Pc mean? Outward or inward force on vessels?
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hydrostatic pressure of capillary bed (capillary BP); outward
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What does pieC stand for? Inward or outward force on vessel?
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protein osmotic pressure of capillary; inward
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What does PIF stand for? Inward or outward force on vessel?
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hydrostatic pressure of interstitial fluid; inward
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What does pieIF stand for? Inward or outward force on vessel?
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protein osmotic pressure of interstitial fluid; outward
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Where does isotonic saline distribute? What is the effect on plasma oncotic pressure and BP?
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ECF space; lowers plasma oncotic pressure; increases BP
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Where does plasma or whole blood distribute? What is the effect on plasma oncotic pressure and BP?
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remains in vascular space; maintains plasma oncotic pressure; increases BP
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What will liver disease or nephrotic syndrome cause? Which Starling force is affected?
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edema; decreases pieC
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What will increased protein permeability of capillary endothelium cause (burns, inflammation, trauma)? What Starling force is affected?
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edema; increases pieIF
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What will left heart failure cause? What Starling force is affected?
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edema; increases Pc
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What does blockage of lymph flow cause? What are two things that can cause this?
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edema; elephantitis caused by the filarial worm or types of surgery that remove lymph nodes or obstruct lymph ducts
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What are podocytes?
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cells of visceral epithelium
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All nerves to the kidney are SNS or PNS?
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SNS
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What cells of the kidney secrete renin?
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JG cells
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What is filtration?
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movement of ultrafiltrate of plasma into Bowman's space
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What is reabsorption?
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movement of water and solutes from tubule to peritubular capillaries
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What is secretion?
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movement of water and solutes from peritubular fluid to tubule
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What is excretion?
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removal of substances from body into urine
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Excretion = ?
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filtration + reabsorption +
secretion |
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What are examples of things that are completely reabsorbed?
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glucose, AAs
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Can proteins travel through the tight junctions that join cells?
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no
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Moving from the tubular lumen into the peritubular capillaries is?
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reabsorption
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Moving from the peritubular capillaries into the tubular lumen is?
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secretion
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What is the term for movement through cells?
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transcellular
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What is the term for movement between cells?
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paracellular transport
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Filtration depends on what two things?
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size and charge
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The basement membrane and the filtration slits have a net _____ charge.
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negative; therefore they repel proteins
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What is the filtrate?
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what gets through the filtration barrier and into Bowman's space
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What is the filtrand?
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where the filtrate comes from...the plasma
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If a substance is perfectly filtered, what is the concentration of the filtrate/filtrand
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1.0
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If a substance is not filtered at all, what is the value for the concentration of the filtrate/filtrand?
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0.0
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Most substances with a MW<5000 are?
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freely filtered
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Charge on a substance becomes inportant when MW?
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increases above 5000
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Are positively charged things easily filtered or hard to filter?
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easily filtered
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What is minimal change disease?
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nephrotic syndrome secondary to charge disruption of the filtration barrier
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What are some properties of glomerular capillaries in relation to muscle capillaries?
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-shorter and fatter
-minimal BP drop throughout length -similar size selectivity -100X permeability for water and ions -filter about 20% plasma vs 1% |
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What is Pbc?
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pressure of Bowman's capsule; pressure that drives fluid through nephron
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What is Pgc?
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pressure of glomerular capillaries that drives fluid into Bowman's capsule
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What is pieGC?
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oncotic pressure in the glomerular capillaries; opposes filtration
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As protein content increases, what happens to oncotic pressure?
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increases
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What are the properties of inulin?
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-freely filtered
-not reabsorbed -not sereted -not metabolized or synthesized |
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What can be used to calculate GFR?
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inulin
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Inulin filtered = ?
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Inulin excreted
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What does volume x conc. = ?
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weight
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How do you calculate GFR?
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((inulin)urine x urine flow)/
(inulin)plasma |
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What besides inulin can be used to calculate GFR?
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creatinine
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What are the properties of creatinine?
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-freely filtered
-not reabsorbed -slightly secreted |
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What is the defintion for clearance? What are the units for clearance?
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the volume of plasma that contains the amount excreted; ml/min
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GFR + 10% = ?
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clearance of creatinine
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How can you measure renal plasma flow?
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using pAH
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Clearance of pAH is about what % of renal plasma flow?
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90%
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How do you calculate true renal plasma flow?
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CpAH/0.9
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Order these substances from highest clearance to lowest clearance?
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pAH > creatinine > inulin
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If Cx > Cinulin, then x is?
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filtered and secreted
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If Cx = Cinulin, then x is?
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probably a glomerular substance for example mannitol
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If Cx < Cinulin, then x is?
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filtered and partially reabsorbed for example urea
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If Cx = 0, then x is?
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not filtered, or filtered and entirely reabsorbed
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If Cx = CpAH, then x is?
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filtered and entirely secreted
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How is GFR affected by increasing glomerular capillary pressure?
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increases
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If you double MAP in a pt and then measure their GFR, you won't see much change in GFR because of?
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autoregulation
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Which arteriole tone, the afferent or the efferent, affects renal blood flow and GFR?
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afferent
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What are the 3 mechanisms of afferent arteriole contraction?
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myogenic, tubuloglomerular feedback, mesangial cell contraction
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What is the myogenic mechanism of arteriole contraction?
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stretch of the afferent arteriole SM causes contraction (opening stretch-activated cation channels leads to depolarization which causes Ca++ influx and therefore contraction)
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What is the tubuloglomerular feedback mechanism of arteriole contraction?
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increased Na+ or Cl- at the macula densa which leads to ATP or adenosine release which causes arteriolar constriction
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What effect does adenosine have in the kidney?
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vasoconstriction
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What effect does adenosine have in the heart?
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vasodilation
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What is the mesangial cell contraction mechanism of afferent arteriole contraction?
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ATP or adenosine also causes mesangial cell contraction which leads to dec RBF and dec GFR
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What are the effects on the afferent and efferent arterioles with mild SNS activity? GFR? RBF?
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both afferent and efferent constrict; GFR has no change; RBF dec
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If GFR stays constant and RBF dec, what happens to the filtration fraction?
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increases
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What is the filtration fraction?
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GFR/RBF
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What is another name for JG cells?
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granular cells
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SNS directly acts on alpha-1 receptors of smooth muscle cells in the afferent or efferent arteriole of the kidney?
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afferent
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SNS acts on beta-1 receptors of JG cells in the afferent or efferent arteriole of the kidney?
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efferent
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What does efferent arteriole constriction cause?
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renin release which leads to AII
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Does AII preferentially constrict the afferent or efferent arteriole?
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efferent
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What do prostaglandins do in the kidney? Which ones act in the kidney?
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cause vasodilation and therefore help to modulate SNS activity on the kidney; PGE2 and PGI2
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What are prostaglandins formed from?
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arachidonic acid
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What do NSAIDS do?
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block the synthesis of prostaglandins
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Why should you be careful using NSAIDS in pts with cardiac failure?
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they will have severe constriction of the afferent and efferent arterioles which will greatly reduce their RBF and GFR
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What is the function of ACE inhibitors or ARBS on the kidney?
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decreased AII and therefore relaxation of the efferent arteriole
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What drugs should be used with extreme care in pts with impaired cardiac output?
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NSAIDS and ACE inhibitors or ARBS
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What stimulates the release of ANP?
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increased blood volume
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What are the effects of ANP on GFR, RBF, and Na+ excretion?
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increases all three
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What are the three main ways to stimulate renin release?
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1)dec afferent arteriole pressure
2)inc SNS activity 3)dec Na+ and Cl- at the macula densa |
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What does BUN depend on?
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protein intake, GFR, and hydration state
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Is the BUN going to be high or low in the GFR is low?
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high
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BUN reabsorption increases as levels of what increase?
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ADH
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Does BUN inc or dec with dehydration?
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increase
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What relationship do the BUN and creatinine concentrations have to GFR?
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they are inversely proportional to 1/GFR
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What is a normal creatinine level?
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about 1mg/dL
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What is a normal BUN level?
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about 15mg/dL
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If the GFR is reduced, what will happen to the BUN/creatinine ratio?
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unchanged (about 15)
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If a pt is dehydrated, what will happen to the BUN/creatinine ratio? What is the condition called?
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increase; pre-renal azotemia
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Does the creatinine level inc or dec with renal failure?
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inc
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Does the creatinine level inc or dec with dehydration?
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doesn't change much
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What is the order of reliability methods for determining the GFR?
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creatinine clearance > serum creatinine conc. > BUN
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What is a normal GFR?
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about 120ml/min
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What are some examples of substances absorbed by Tm dependent mechanisms?
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glucose, galactose, AAs, organic acids, phosphate, sulfate, vitamin C
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What hormone regulates phosphate reabsorption?
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PTH
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Are Tm dependent substances freely filtered?
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yes
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Where are Tm dependent substances reabsorbed from?
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proximal tubule
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How are Tm dependent substances transported?
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transported at the luminal membrane by Na+ linked cotransport (symport)
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Do Tm dependent substances show saturation? Do they have a high or low Vmax?
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yes; low Vmax
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How do you calculate the excretion rate of glucose?
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Uglu x V
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How do you calculate the filtered load of glucose?
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GFR x Pglu
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How do you calculate the glucose reabsorbed?
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glu filtered - glu excreted
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What is the plasma threshold for glucose?
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about 200 ml/dL
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<10% of plasma phosphate is protein-bound which means?
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it is freely filtered
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On a normal diet, how much phosphate is reabsorbed? How much is excreted?
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about 90%; about 10%
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Where is most of the phosphate reabsorbed?
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proximal tubule
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Does PTH cause increased or decreased phosphate excretion?
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decreased reabsorption and therefore increased excretion
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What happens to plasma Ca++ levels if plasma phosphate levels increase?
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decrease
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What is secondary hyperparathyroidism?
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dec GFR (renal failure) causes dec phosphate excretion and therefore increased serum phosphate; this means that plasma Ca++ is dec which will stimulate inc PTH release
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Where is most of the Ca++ in our bodies?
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99% in bone as Ca++ hydroxyapatite
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What are the three ways Ca++ is found in the plasma?
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1)50% ionized
2)10% complexed to citrate and phosphate 3)40% protein-bound |
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What percent of plasma Ca++ is filtered?
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60%
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What happens to the level of ionized Ca++ if the pH is decreased? What can this lead to?
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Ca++ inc; can lead to arrhythmias and decreased neuromuscular excitability
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Do Tm dependent substances show saturation? Do they have a high or low Vmax?
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yes; low Vmax
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How do you calculate the excretion rate of glucose?
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Uglu x V
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How do you calculate the filtered load of glucose?
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GFR x Pglu
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How do you calculate the glucose reabsorbed?
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glu filtered - glu excreted
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What is the plasma threshold for glucose?
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about 200 ml/dL
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What happens to the level of ionized Ca++ if the pH increases? What can this lead to?
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Ca++ decreases; hypocalcemic tetany
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What hormone regulates the body's Ca++ level?
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PTH
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What hormone has opposite effects of PTH?
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calcitonin
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What is the active form of vitamin D?
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1,25(OH)2D3
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What type of hormone is PTH and where is it released from?
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peptide hormone; parathyroid gland
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What is the stimulus for PTH release?
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low plasma Ca++
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What is another name for Vit.D?
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calcitriol
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What are the two overall effects of PTH?
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increase plasma Ca++ and decrease plasma phosphate
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What are the 4 actions of PTH?
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1)inc bone resorption which will inc plasma Ca++ and P
2)inc renal hydroxylase enzyme which inc active Vit.D synthesis which inc intestinal Ca++ and P absorption 3) inc renal Ca++ reabsorption 4)dec renal P reabsorption |
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How much Ca++ is filtered?
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60% that is not protein-bound
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How much Ca++ is reabsorbed?
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99% of the filtered load
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How is Ca++ reabsorbed in the proximal tubule?
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paracellular
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How is Ca++ reabsorbed in the thick ascending limb?
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50% paracellular, 50% transcellular
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How is Ca++ reaborbed in the distal tubule?
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transcellular
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PTH causes increased reabsorption of Ca++ in what part of the kidney?
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distal tubule
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What is the end product of purine metabolism?
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uric acid
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What causes gout?
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increased plasma levels of uric acid accumulating out in joints
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What is the function of allopurinal?
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xanthine oxidase inhibitor; decreases plasma uric acid concentrations; purines are then excreted as the more soluble hypoxanthine
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Is uric acid freely filtered? How much of the filtered urate is excreted?
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yes; 10%
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