1
cystometogram
• Shows the approximate changes in intra vesicular pressure as the bladder fills with urine
• Pressure peaks are called micturition waves in the cystometogram and caused by the micturition reflex
3
Posterior urethra
• Internal sphincter
• External sphincter –voluntary skeletal muscle – under voluntary control
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Reflex and Voluntary Control of Micturition
• Bladder filling reflexively contracts the bladder
• Internal Sphincter mechanically opens
• Stretch receptors in bladder send inhibitory impulses to external sphincter
• Voluntary signals from cortex can override the reflex or allow it to take place
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Diuretics
• Diuretics are the drugs thst promote diuresis and decrease ECF volume
Loop diuretics – furosemide – lasix ethacrynic acid they inhibit Na+ - K+ - Cl – cotransporter in
the thick loop of Henle
28
Aldosterone antagonists – K+ sparring diuretics , inhibits Na+ - K+ exchange and leads to natriuresis and diuresis with retention of K+
spironolactoneThiazide diuretics – inhibit Na+ - Cl-
cotransporter in the early part of distal tubule
chlorothiazide