Chapter 7 (exam 2) Flashcards

1
Q

Kidney Functions

A
  • reg blood volume and pressure
  • ion concentrations
  • regulate pH
  • conserve nutrients and eliminate waste/tox
  • metabolism of drugs/tox
  • filtrations (180L per day)
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2
Q

Bowman’s Capsule

A
  • glomrulus inside with fenestrated capillaries
  • pores in capillary allow small parts to enter the kidney
  • Albumin, blood cells fo not enter the nephron
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3
Q

Proximal Convoluted Tubule

A
  • Retains nutrients (amino acids and glucose) and water
  • active transport to help retain nutrients
  • Pump Na+ out and water will follow due to osmosis (passive)
  • some enzymes pull in Na+ while removing glucose (antiporter)
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4
Q

Loop of Henle

A
  • ion regulation and water reabsorption
  • osmolarity increases in descending limb as water is removed
  • remove salt in ascending limb and decrease osmolarity
  • bottom is highly stressed due to high conc
  • countercurrent with vasa recta blood vessel, more efficient than static system
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5
Q

Osmolarity

A

mole solute/L solution

osmosis - diffusion of water across membrane

increases in descending limb and decreases in ascending limb

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6
Q

Collecting duct

A
  • water balance
  • after PCT
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7
Q

Renal susceptability to Tox

A
  • highly perfused - 20-25% cardiac output
  • high solute conc
  • active transport
  • bioactivation due to metabolic activity
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8
Q

Kidney injuries

A

hypofiltration - decrease rate of filtration due to renal vasocconstriction or glomerular injury (amphotericin B increases permeability, loss gradient)

tubular necrosis - wide variety of chemicals that can cause widespread cell damage

obstruction - loss of flow (radiocontrast agents form precipitate due to high conc in tubular fluid)

fibrosis - immune, inflammatory effect

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9
Q

Measurement of GFR

A
  • glomerular flow rate
  • use serum creatine and urea (blood urea nitrogen, BUN) concentrations as biomarker
  • Constantly generated throughout the body

readily eliminated by the kidney. Increase conc corresponds to decrease in filtration rate

-mass balance (in-out)

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10
Q

Urinalyasis

A

Chemical analysis of solute conc and pH

-proteinuria - protein in the urine (albumin)

–due to injury to the glomerulus via high blood pressure

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11
Q

Ethanol Renal Impact

A
  • inhibit ADH
  • less ADH results in less water reabsorption in the collecting duct
  • less conc urine, higher volume, dehydration
  • ADH promotes water retention via collecting duct
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12
Q

Chlorinated Solvents (Renal)

A
  • TCE - trichloroethylene
  • GSH generates reactive metabolites
  • beta-lyase cleaves the cysteine off of the (-SG) conjagate to form a nucleophile
  • nucleophile is highly reactive and forms an adduct
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13
Q

Metal Renal Tox

A
  • Cd and Hg (non-nutrative metals)
  • Negative effects because of sulfur chemistry
  • transition metals (soft metals, more polarizable) have high affinity for reduced sulfur
  • soft metal has high affinity for soft ligands (O is hard, S is soft)
  • soft metals in bottom right of periodic table
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14
Q

Bio source of Reduced Sulfur

A
  • thiols in proteins, GSH (gluothione conjugation)
  • metal binds to thiol on protein and alters the tertiary sructure
  • loss of function for active transporters required for kidney function
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15
Q

Metallothioneins

A
  • cysteine rich proteins that are used to sequetser nutrient metals like Zn or that serve as non-essential target for toxic metals (Cd)
  • Produced in liver and kidneys
  • Inducible and chronic exposure can increase production therefore it is a biomarker for exposure

-

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16
Q

Metallthioneins mechanism

A
  • metal binds to MTin liver instead of an essential protein
  • metal-MT complex is excreted in urine thorugh the kidney (its small)
  • Cd-MT is reabsorbed in the PCT

–looks like a protein that should be conserved and recycled

  • PCT cell recycles via the lysosome (release Cd2+)
  • Free Cd2+ binds to essential proteins (degrade cell function) or MT in the PCT cell
  • MT supply depleted
17
Q

Pb in the Kidney

A
  • reabsorbed in the PCT
  • binds to sites in mitochondria, decrease energy
  • decrease active transport of essential nutrients being reabsorbed
  • Cisplatin(chemotherapy drug) also binds to mitochondria and inhibits electron transport and generates ROS
  • ROS can alter structure of essential bio molecules
18
Q

Mercury in Kidney

A

50% of dose can be found in the kidney in a few hours

  • PCT necrosis in 24-48 hrs after acute exposure
  • PCT reabsorption decreases and damage to mitochondria
19
Q

Metal Tox in Aquatic system

A
  • related to impacts on gills
  • gill functions - respiration (dissolved gas exchange), ion regulation (osmoregulation), similar to mammal kidney
  • freshwater-uncontrolled lose ions
  • salt water - uncontrolled gain ions or lose water
  • brackish water - isoosmotic
  • Ca2+, Na+, K+, Mg2+ other ions are trace
20
Q

Biotic Ligands (fish gills)

A
  • metals target the biotic ligands (lone pairs, negative charges)
  • ion transport protein
  • Binding affinity series NA<k></k>

<p>-trace ions preferably bind to the ion transport protein</p>

<p>--longer residence time</p>

<p>--inhibit normal ion balance</p>

<p>--lose osmotic balance</p>

<p> </p>

</k>

21
Q

Biotic Ligand Model

A

Zn + Ca-BL equil Zn-BL +Ca

Zn + BL equil Zn-BL Kf

also Zn + Cl equil ZnCl

Competition between trace metals and major ions for the biotic ligand

  • betwen other ligands and metal ions
  • increase in major ion concentration will decrease tox because ion will be more competitive than metal
  • site specific water quality criteria is based on BLM
22
Q

Dissolved Organic Matter

A
  • decay products from platn material, large MW, wide array of sizes and structures
  • contain functional groups that can be ligands