Which of the following is false about the GFR?


a. The GFR averages about 120 ml/min.
b. The GFR increases when the afferent arteriole dilates.
c. The GFR decreases when the efferent arteriole constricts.
d. The GFR decreases when the afferent arteriole constricts

Verified step by step guidance

1. Understand that GFR stands for Glomerular Filtration Rate, which is a measure of how much blood is filtered by the glomeruli in the kidneys per minute.
2. Recall that the GFR is influenced by the diameter of the afferent and efferent arterioles, which control blood flow into and out of the glomerulus.
3. Consider that dilation of the afferent arteriole increases blood flow into the glomerulus, potentially increasing the GFR.
4. Consider that constriction of the efferent arteriole increases pressure in the glomerulus, potentially increasing the GFR, not decreasing it.
5. Evaluate each statement based on these principles to determine which one is false.

Key Concepts

Glomerular Filtration Rate (GFR)

GFR is a measure of how well the kidneys filter blood, specifically the volume of fluid filtered from the renal glomeruli into the Bowman's capsule per minute. An average GFR is about 120 ml/min in healthy adults, indicating efficient kidney function. It is a critical parameter in assessing renal health and function.

Afferent and Efferent Arterioles

The afferent arteriole supplies blood to the glomerulus, while the efferent arteriole carries blood away from it. Dilation of the afferent arteriole increases blood flow into the glomerulus, thereby increasing GFR. Conversely, constriction of the efferent arteriole can increase GFR by raising pressure within the glomerulus.

Regulation of GFR

GFR is regulated by various mechanisms, including changes in the diameter of the afferent and efferent arterioles. Constriction of the afferent arteriole reduces blood flow into the glomerulus, leading to a decrease in GFR. Understanding these regulatory mechanisms is essential for interpreting changes in kidney function and diagnosing renal conditions.