PHSI 208 Lecture 5: PHSI 208.6 Renal 5 (LB)
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Clearance of (ml/min) = excretion rate of (mg/min) A given amount of plasma will have all solute filtered within a minute. The solute excreted is the glomerular filtration rate. Clearance of a substance that is freely filtered and neither reabsorbed nor secreted will equal that individual"s gfr. If this person"s gfr is 125 ml/min, you know there is net reabsorption of solute. = (100 mg glucose / 100 ml plasma) * 125 ml plasma/min. = 125 mg glucose/min: realistically, glucose is completely reabsorbed. Filtered load: how much solute is filtered based on plasma concentration multiplied by gfr. The concentration, or osmolarity, of urine is a measure of how much water is excreted by the kidneys. When the removal of excess water is required, the kidneys produce lots of dilute urine with an osmolarity as low as 50mosm1. The removal of excess urine is known as diuresis. A signal is sent to the kidneys if water conservation is necessary.
