Glomerular filtration rate (GFR)

Definition

Glomerular filtration rate (GFR) is the volume of fluid filtered from the renal glomeruli into the Bowman's capsule per unit time, typically measured in milliliters per minute. GFR is a crucial indicator of kidney function, reflecting how well the kidneys are filtering blood and removing waste products. It provides insight into nephron performance, as the nephron is the functional unit of the kidney responsible for filtration and reabsorption processes.

5 Must Know Facts For Your Next Test

1. Normal GFR ranges from about 90 to 120 mL/min in healthy adults, with variations depending on age, sex, and body size.
2. GFR can be affected by various factors such as blood pressure, hydration status, and overall health, making it a vital measure in assessing kidney health.
3. Clinical assessments of GFR often use serum creatinine levels to estimate kidney function, as elevated creatinine levels indicate reduced GFR.
4. A decline in GFR is an early sign of kidney disease and can progress to end-stage renal failure if not addressed.
5. GFR can be influenced by medications, as some drugs may constrict or dilate renal blood vessels, altering the filtration rate.

Review Questions

• How does glomerular filtration rate (GFR) relate to nephron function and kidney health?
  • GFR is a direct measure of how effectively the nephrons filter blood. Each nephron contains a glomerulus where filtration occurs, and a high GFR indicates that nephrons are functioning well to remove waste and excess substances from the bloodstream. Conversely, a low GFR suggests impaired nephron function, which can lead to the accumulation of toxins in the body and signifies potential kidney problems.
• Discuss the clinical significance of measuring glomerular filtration rate (GFR) in diagnosing kidney disease.
  • Measuring GFR is essential for diagnosing kidney disease because it provides insight into the kidneys' filtering capacity. An estimated GFR based on serum creatinine levels helps healthcare professionals assess kidney function and identify conditions like chronic kidney disease or acute kidney injury. Early detection through GFR measurements allows for timely intervention and management strategies to prevent further decline in kidney health.
• Evaluate the impact of decreased glomerular filtration rate (GFR) on systemic health and potential treatment approaches.
  • A decreased GFR can lead to serious systemic health issues due to the buildup of waste products in the blood, causing complications like hypertension, electrolyte imbalances, and uremia. This decline can also increase cardiovascular risk. Treatment approaches may include managing underlying conditions, adjusting medications affecting renal function, dietary modifications, and in severe cases, renal replacement therapies such as dialysis or transplantation to restore proper filtration and maintain homeostasis.

Related terms

Nephron: The basic structural and functional unit of the kidney, responsible for filtering blood, reabsorbing essential nutrients, and excreting waste as urine.

Renal Blood Flow: The volume of blood delivered to the kidneys per unit time, which is essential for maintaining a healthy GFR and overall kidney function.

Creatinine Clearance: A test that estimates GFR by measuring the rate at which creatinine, a waste product from muscle metabolism, is cleared from the blood.