mana70
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please maybe somebody can explain to me in simple english what means excretion reabsorption, filtretion and secretion and clearence, also i dont know how to memorize those formulas please i need your help urgently.
thank you
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| mjl1717
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Excretion-what you urinate, its in the final urine
Mathematically its: urinary conc. times vol. of urine
Reabsorbtion--what goes from the tubular fluid back into plasma
Mathematically:Reabsorbtion =filtration -excretion
{Quickly- filtration is relative to the quantity of renal plasma flow}
Comments.
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| phuluong2k
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In normal people
renal plasma flow is 600ml/mn :arrow: Only 120 ml is filtered at the nephrons :arrow: It is Glomerular filtration rate, simply Filtration
The tubular section has 2 roles
:arrow: Reabsorb some subtances such as glucose, Sodium, Urea etc :arrow: Reabsorption
:arrow: Secrete some subtances such as creatinine :arrow: Secretion
Excretion as mjl say, it is what in the urine
:arrow: Excretion = Filtration ( Inulin, Manitol) no secrete nor reabsorb
:arrow: Excretion = Filtration - Reabsorption ( reabsorbed Glucose, Sodium, Urea)
:arrow: Excretion = Filtration + Secretion ( secreted PAH & Creatinine)
Clearance is the theoretical plasma volume for subtance that is removed
Formula Clearance = [ Urine volume x Subtance concentration in urine ]/ Subtance concentration in plasma
Example:
:arrow: Glucose is reabsorbed totally at the proximal tubule :arrow: Urine concentration = 0 :arrow: Clearance = 0
:arrow: Inulin, neither reabsorbed nor secreted :arrow: Clearance = 120 ml/mn
:arrow: Inulin is only filtered, neither secreted nor reabsorbed :arrow:
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| mana70
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thank you so much guys only thing is not clear is secretionwhat is mean it made in tubule or what , renal physio is killing me. i am very bad in memorization, if i don't understand. thank you again
mana
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| phuluong2k
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http://academic.pgcc.edu/~aimholtz/AandP/206_ONLI...
I think this visual effect can help you
Finally urine = Excretion
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| mana70
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thank you image really helped. know i have to worry remembering those formulas.good luck
mana
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| mjl1717
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Phuluong-With all due respect in your first sentence with the ratio of
{GFR/renal plasma flow} some books call that filtration fraction which is usually about 20%. The other 80% passes via the efferent arteriole into the peritubular capillaries.
As far as I know only glucose and amino acids are totally reabsorbed.
Although we said Tamm Horsefal protein is normal
Reabsorbtion greatest to least approximately)
1)Glucose, amino acids, protein
2)sodium-99.5%, water-99%
3)urea-50%
4)inulin-As phuluong said its filtered
5)creatinine, PAH
The % is percent reabsorbtion.
LAST POINT:Whenever the clearance of a substance is greater then inulin
clearance, tubular secretion of that substance must have occured.
Next time: Ill go into details about creatinine and PAH unless phuluong wants to take it.
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| phuluong2k
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Hi, very good mjl information
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| yxcl
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That is a great help for me. Thanks, guys.
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