Does an increase in hydrostatic pressure in bowman’s capsule increase or decrease glomerular filtration rate?
The correct answer and explanation is:
Correct Answer: Decrease
An increase in hydrostatic pressure in Bowman’s capsule leads to a decrease in the glomerular filtration rate (GFR). The glomerular filtration rate is the rate at which fluid is filtered from the glomerular capillaries into Bowman’s capsule in the kidneys. It is primarily determined by the balance of pressures acting across the glomerular membrane. These include the glomerular capillary hydrostatic pressure, the colloid osmotic pressure of the blood plasma, and the hydrostatic pressure in Bowman’s capsule.
The glomerular capillary hydrostatic pressure pushes fluid out of the capillaries into the capsule. In contrast, the hydrostatic pressure in Bowman’s capsule resists this movement by pushing fluid back into the capillaries. Therefore, when the pressure in Bowman’s capsule increases, it directly opposes the filtration pressure. This reduces the net filtration pressure, leading to a decreased glomerular filtration rate.
Several conditions can lead to an increased hydrostatic pressure in Bowman’s capsule. One example is a blockage in the urinary tract or ureter, which can cause a backup of urine and raise the pressure in the nephron, including Bowman’s capsule. This can ultimately reduce the ability of the kidneys to filter blood efficiently. Similarly, kidney stones or other obstructions may also have the same effect.
Maintaining proper pressure dynamics within the nephron is essential for normal kidney function. When pressure in Bowman’s capsule rises, it interferes with the normal filtration process. Over time, reduced filtration can lead to the buildup of waste products in the blood and potentially contribute to kidney damage if the condition persists.
Thus, increased hydrostatic pressure in Bowman’s capsule is a negative factor that reduces glomerular filtration rate by directly counteracting the driving force of filtration from the glomerular capillaries.