renal 4 Flashcards
what is renal clearance?
-provides a clearance value in terms of the amount of plasma completely cleared of a given substance in one minute
a non-invasive method using collected urine and a blood sample to:
- calculate GFR: if you can find a substance that is filtered, not reabsorbed and not secreted. Filtered load=excreted load
2.understand the net renal handling of any filtered solute
what is the graph of glucose clearance?
what is the graph of urea clearance?
what is the graph of penicillin clearance?
what does the comparisons of clearance values tell us?
-the net handling of a solute
ex: nearly all K is filtered is reabsorbed, but a small amount is secreted back in, but this method would only indicate a net reabsorption
what happens when GFR=clearance and filtered=excreted?
example of inulin
-filtered, not reabsorbed, not secreted
what happens when GFR>clearance and filtered>excreted?
example of glucose, urea
-filtered and net reabsorption
what happens when GFR<clearance and filtered<excreted?
example of penicillin
-filtered and net secretion
filling of the bladder activates stretch receptors initiating the __________________
MICTURITION REFLEX
-ureters undergo rhythmic contractions (pacemaker cells)
what is the graph of bladder at rest?
in toddler, just comes out
what is the graph of micturition (urination)?
when does the urge to urinate happen?
-urge to urinate appears around 200mL
-once exceeding 500mL, internal sphincter forced open, leading to reflexive opening of the external sphincter and loss of voluntary opposition
-around 10mL left in bladder after micturition
-(descending can inhibit so we can control until 500mL)
what is the spiderweb of micturition?
what may cause the inability to control urination voluntarily?
-infants: corticospinal connection necessary for voluntary control have yet to be established
-damage to internal or external sphincter (pregnancy)
-spinal cord damage (prevent input for inhibition)
-aging
