GFR & IT’S Regulation

By:-Dr.Pradeep Sharma

PG ( Res.)SMS ,medical college.jaipur

GOOD MORNING

GFR & IT’S REGULATION

Glomerular filtration rate (GFR) is the measure that describes the total

amount of filtrate formed by all the renal corpuscles in both kidneys per

minute.

• Glomerular filtration is first step of urine formation.

• It’s begin with filtration of large amounts of fluid through glomerular capillaries in to Bowman’s capsule.

• Glomerular capillaries are impermeable to proteins, cellular elements including RBC’s

• Filtered fluid through glomerular capillaries called glomerular filtrate.

• Some LMWS ( like calcium, fatty acids ) are not freely filtered, because of partilally bound to plasma proteins

• Glomerular filtration rate (GFR) is equal to the Clearance Rate when any solute is freely filtered and is neither reabsorbed nor secreted by the kidneys.

Urine concentration * Urine flow• GFR = Plasma concentration

Estimation of GFR

1) Measurement using inulin/ sinistrin ( most accurate) 2) Measurement with radioactive tracers (Chromium- 51 and 99 m- T) 3) Creatinine-based approximations of GFR. ( most clinically used)

U cr * VCcr = P crExample: A person has a plasma creatinine

concentration of 0.01 mg/ml and in 1 hour produces 60ml of urine with a creatinine concentration of 1.25 mg/mL.

REGULATION OF GFR

Renal blood flow & GFR

• 1) Auto regulation• 2) Neural (autonomic ) regulation• 3)Hormonal regulation• 4) RAAS (renin-angiotensin- aldosteron

system)

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