Renal 4 Flashcards
Clearence
to measure GFR
Understand net handling of a speific molecule
Rate of excretion
Formula for clearence
Excretion rate of x / Substance concentration in plasma
measures in ml/min
Unulin
Polysaccharide found in a variety of plants was found in isolated nephrons to be completely filtered and not reabsorbed
Filtered load of X
Concentration of x in plasma (GFR)
Filteration load of inulin
Excretion rate of inulin
Excretion rate of inulin
Concentration of inulin in plasma (GFR)
GFR =
Excretion rate of inulin / concentration of inulin in plasma
Clearence of x =
Excretion rate of x / concentration of x in plasma
What do clinicians commonly use to calculate GFR
They use Creatnine
What is creatine a product of
Phosphocreatinbreakdown
Is creatine filtered
Yes but it is secreted in very small amounts as well
Why do we measure GFR
to find overall kidney functioning
Filtered Load
Concentration of plasma x GFR
How do we know if net reabsorbtion rate has occured
If less of a substance appears in the urine than was filtered
How do we know if net secretion is occured
If more subsate appears in urine that it was filtered
Net reabsorbtion occurs with
Glucose and urea
net secretion occurs with
Penicilin
Micturition reflex
Filling of the bladder activates stretch receptors initiating the micturition reflex
Steps of Micturiotion reflex
- Filling up bladder
- Filling exceeds 200mls
- Walls will distend slightly
- Strech receptors fire
- Parasympathetic neurons fire and bladder expands
- Smooth muscle contracts. Internal sphincter is passively pulled open. External Sphincter relaxes
Bladder and what is the wall made up ofp
Filling of urine happens here
Walls made of smooth muscle called Detrusor muscle
Internal sphicter
Passively contracted
Smooth muscle
Some sympathetic input into it
External sphincter
Skeletal muscle
Stays contracted
Has tonic output
Incontinenece
Inability to control urination voluntarily
Incontinence in infants
Corticospinal connections neceesary for voluntary control have yet to be established
Four parameters of fluid electrolyte balance
Fluid volume
Osmolarity
Concentrations of individual ions
pH
Contraction of bladder walls involves an increase in
Parasympathetic activity
Contraction of internal sphincter
Sympathetic
Control of External sphincter
Somatic motor
