Question

What happens to the glomerular filtration rate (GFR) if blood pressure in the kidneys increases?

Answer 1

Hint: The nephrons present in the kidney contains a large and dense network of blood capillaries. A high volume of blood flows through these nephrons regularly. Pressure gradient in the glomerulus leads to glomerular filtration.

Complete answer:
Glomerular filtration rate or GFR is the rate of formation of the total amount of filtrate by the renal corpuscles per minute in both kidneys. It is directly proportional to the pressure gradient in the glomerulus. Change in pressure leads to a change in the glomerular filtration rate. An increase in blood volume and blood pressure leads to an increase in the glomerular filtration rate. GFR indicates urine production and the increased GFR increases urine production while the decreased GFR decreases it. It is also affected by the pressure changes within the afferent and efferent arterioles. Vasodilation in the afferent arteriole and vasoconstriction in the efferent arteriole leads to an increase in blood flow and hydrostatic pressure in the glomerulus. This leads to an increase in GFR. Similarly, vasoconstriction in the afferent arteriole and vasodilation in the efferent arteriole leads to a decreased GFR. Therefore, Glomerular filtration rate (GFR) will increase if the blood pressure in the kidneys increases.

Additional Information: Uncontrolled high blood pressure over time causes narrowing, weakening and hardening of arteries around the kidneys. Due to the damage, these arteries are unable to deliver the required blood to the kidney tissue.

Note: Constriction of the afferent arterioles and dilation of the efferent arterioles leads to a decrease in Glomerular Filtration Rate. The hydrostatic pressure in the Bowman’s capsule decreases the GFR. The standard osmotic pressure in the Bowman’s space is zero, but if it becomes leaky, the osmotic pressure increases and GFR decreases. Low GFR activates the renin-angiotensin feedback system that increases the blood volume in response to the low GFR.