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Does dilation of the afferent arteriole and constriction of the efferent arteriole decrease GFR?
Dilation of the afferent arteriole increases blood flow into the glomerulus, which typically raises glomerular filtration rate (GFR). Conversely, constriction of the efferent arteriole reduces blood outflow from the glomerulus, which can also increase GFR. Therefore, the combination of afferent dilation and efferent constriction would generally not decrease GFR; instead, it could either maintain or potentially increase GFR depending on the extent of the changes.
What do you think the sympathetic nerves do to the afferent arteriole?
Sympathetic nerves primarily cause vasoconstriction of the afferent arteriole. This response reduces blood flow into the glomerulus, leading to a decrease in glomerular filtration rate (GFR). The activation of sympathetic nerves is typically part of the body's response to stress or low blood pressure, helping to conserve fluid and maintain blood volume. Overall, this mechanism plays a crucial role in regulating renal blood flow and maintaining homeostasis.
What is the effect of constricted arterioles in the glomerular filtration rate?
Constricted arterioles in the glomerulus can lead to a decrease in the glomerular filtration rate (GFR) by reducing the amount of blood flow entering the glomerulus. This can result in decreased filtration of waste and reduced urine production.
How does a nephron maintain a near-constant glomerular filtration rate?
A nephron maintains a near-constant glomerular filtration rate (GFR) primarily through autoregulation, which involves mechanisms like myogenic response and tubuloglomerular feedback. The myogenic response adjusts the diameter of afferent arterioles in response to changes in blood pressure, helping to stabilize blood flow to the glomerulus. Tubuloglomerular feedback involves the detection of sodium chloride concentration by the macula densa cells; if GFR is too high, these cells signal the afferent arteriole to constrict, reducing filtration rate. Together, these mechanisms ensure that GFR remains relatively constant despite fluctuations in systemic blood pressure.
What effect does sympathetic stimulation have on the afferent arterioles?
Sympathetic stimulation causes vasoconstriction of the afferent arterioles in the kidneys. This response reduces blood flow into the glomeruli, which can decrease glomerular filtration rate (GFR). The effect is part of the body's mechanism to prioritize blood flow to vital organs during stress or low blood volume situations. Ultimately, this helps conserve water and maintain blood pressure.
Does dilation of the afferent arteriole and constriction of the efferent arteriole decrease GFR?
Dilation of the afferent arteriole increases blood flow into the glomerulus, which typically raises glomerular filtration rate (GFR). Conversely, constriction of the efferent arteriole reduces blood outflow from the glomerulus, which can also increase GFR. Therefore, the combination of afferent dilation and efferent constriction would generally not decrease GFR; instead, it could either maintain or potentially increase GFR depending on the extent of the changes.
Which arteriole radius adjustment was more effective at compensating for the effect of low blood pressure on the glomerular filtration rate?
The adjustment of the afferent arteriole radius is more effective at compensating for low blood pressure and maintaining glomerular filtration rate (GFR). By dilating, the afferent arteriole increases blood flow into the glomerulus, which helps to counteract the decreased pressure and support GFR. In contrast, constricting the efferent arteriole primarily serves to increase resistance and can help preserve GFR, but its effect is less direct compared to the afferent arteriole's role in enhancing inflow.
What is the effect of reducing afferent arteriole radius on filtration rate?
As the afferent arteriole dilates it exposes the glomerulus to an increased blood pressure, closer and closer to that of the full systemic blood pressure. This increases GFR and Glomerular pressure. -6th Year Medical Student
Is the glomerular filtration rate the same when the efferent arteriole is constricted and dilated?
OLD, INCORRECT ANSWER: Changes in the diameter of the efferent arteriole will either increase (dilation) or decrease (constriction) the blood flow to the glomeruli. An increased flow means a more blood getting filtered over time. NEW, CORRECT ANSWER The 'efferent' arteriole leaves the renal corpuscle. It is easy to remember which direction efferent and afferent things are going by thinking e=exit and a=arrive. If you constrict the efferent arteriole, you actually inhibit blood from leaving the glomerulus, thus increasing the outward hydrostatic pressure pushing fluid into Bowman's capsule and increasing filtration. If you dilate the efferent arteriole, then you reduce pressure in the glomerular capillaries and reduce filtration.
What do you think the sympathetic nerves do to the afferent arteriole?
Sympathetic nerves primarily cause vasoconstriction of the afferent arteriole. This response reduces blood flow into the glomerulus, leading to a decrease in glomerular filtration rate (GFR). The activation of sympathetic nerves is typically part of the body's response to stress or low blood pressure, helping to conserve fluid and maintain blood volume. Overall, this mechanism plays a crucial role in regulating renal blood flow and maintaining homeostasis.
How do you increase your GFR?
To increase your glomerular filtration rate, blood flow needs to be increased to the kidneys and the impaired kidneys function restored. The glomerular filtration rate, of GFR, measures how much blood passes through the glomeruli into the kidneys each minute.
What is the effect of constricted arterioles in the glomerular filtration rate?
Constricted arterioles in the glomerulus can lead to a decrease in the glomerular filtration rate (GFR) by reducing the amount of blood flow entering the glomerulus. This can result in decreased filtration of waste and reduced urine production.
Why ACE inhibitor contraindicated in renal artery stenosis?
In the presence of renal artery stenosis, the resistance in the afferent arteriole is increased. As compensation, Angiotensin II acts to constrict the efferent arteriole in order to achieve adequate profusion of the glomerulus. ACE inhibitors block the conversion of angiotensin I into angiotensin II. Without its vasoconstrictive effect, the efferent arteriole becomes dilated. This leads to a drop in GFR and may lead to renal failure.
How does a nephron maintain a near-constant glomerular filtration rate?
A nephron maintains a near-constant glomerular filtration rate (GFR) primarily through autoregulation, which involves mechanisms like myogenic response and tubuloglomerular feedback. The myogenic response adjusts the diameter of afferent arterioles in response to changes in blood pressure, helping to stabilize blood flow to the glomerulus. Tubuloglomerular feedback involves the detection of sodium chloride concentration by the macula densa cells; if GFR is too high, these cells signal the afferent arteriole to constrict, reducing filtration rate. Together, these mechanisms ensure that GFR remains relatively constant despite fluctuations in systemic blood pressure.
In the absence of any regulatory mechanisms what effect do you think an increase in blood pressure would have on glomerular filtration rate?
Generally speaking, it would increase. However, it depends on the reason for the hypertension. For instance, if there is an obstruction or constriction of the renal artery (stenosis, malignancy, etc...) the physiologic affect would to increase the body's BP. This is due to the fact that the obstruction is decreasing hydrostatic pressure to the glomerulus, and transiently decreasing GFR. The body compensates by increasing BP to increase GFR. Patients that present with a renal artery stenosis could in fact be hypertensive with a decreased GFR.
What happens if the diameter of the efferent arteriole is constricted?
When the afferent arteriole is constricted it causes blood to be unable to flow into the glomerulus, overall decreasing hydrostatic pressure and causing the bowman's capsule to decrease filtration.
What releases when the sympathetic nervous system responds to a decrease in glomerular filtration rate?
Increased sympathetic activity causes the afferent arterioles of the renal glomerulus to constrict, thereby reducing blood flow into the glomerulus. Because a decrease in blood flow reduces blood pressure in the glomerulus, which is the driving force for filtration, GFR decreases.
