Increased blood volume and increased blood pressure directly increase the glomerular filtration rate (GFR).
Understanding GFR
The glomerular filtration rate (GFR) measures how much blood your kidneys filter each minute. A higher GFR indicates that your kidneys are working efficiently. Several factors influence GFR, with blood pressure and volume playing a direct role.
Factors Directly Increasing GFR
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Increased Blood Volume: A larger volume of blood flowing through the glomeruli increases the hydrostatic pressure, pushing more fluid across the filtration membrane and thus raising GFR. This is directly supported by the LibreTexts reference which states that "The increased blood volume with its higher blood pressure will go into the afferent arteriole and into the glomerulus, resulting in increased..." GFR.
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Increased Blood Pressure: Similarly, higher blood pressure forces more fluid through the glomerular capillaries, directly elevating the GFR. The Key Points reference explicitly states that "Increased blood volume and increased blood pressure will increase GFR."
Indirect Factors Influencing GFR
While not directly increasing GFR, factors affecting afferent and efferent arteriolar tone indirectly influence it:
- Constriction of efferent arterioles: Decreasing the diameter of the efferent arteriole increases pressure within the glomerulus, leading to increased GFR. This is consistent with the information from the Physiology journal article which notes that "A decrease in the diameter of the efferent arteriole has the opposite effect".
It's important to note that several other factors can influence GFR, including hormonal regulation and the integrity of the glomerular filtration barrier. However, the question specifically asks about factors that directly increase GFR, and increased blood volume and pressure are the primary ones.
