Glomerular Filtration Rate

Question 1

What is the definition of glomerular filtration rate (GFR)?

Answer 1

Glomerular filtration rate (GFR) is the volume of filtrate produced per minute by the kidneys.

Question 2

Why is GFR an important measure of kidney function?

Answer 2

GFR is an important measure of kidney function because it indicates how well the kidneys are filtering blood.

Question 3

What are the normal values for GFR in healthy adults?

Answer 3

Normal GFR values for healthy adults are approximately 90-120 mL/min/1.73 m².

Question 4

Which equation is commonly used to estimate GFR in clinical practice?

Answer 4

The MDRD (Modification of Diet in Renal Disease) equation and the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation are commonly used to estimate GFR.

Question 5

How does the hydrostatic pressure in the glomerular capillaries affect GFR?

Answer 5

Increased hydrostatic pressure in the glomerular capillaries increases GFR.

Question 6

What role does the colloid osmotic pressure in the glomerular capillaries play in GFR?

Answer 6

Colloid osmotic pressure in the glomerular capillaries opposes filtration, thereby reducing GFR.

Question 7

How does Bowman’s capsule hydrostatic pressure influence GFR?

Answer 7

Increased Bowman’s capsule hydrostatic pressure decreases GFR.

Question 8

What effect does systemic blood pressure have on GFR?

Answer 8

Increased systemic blood pressure generally increases GFR, while decreased blood pressure reduces GFR.

Question 9

How does the afferent arteriole diameter affect GFR?

Answer 9

Dilation of the afferent arteriole increases GFR by increasing blood flow into the glomerulus.

Question 10

How does the efferent arteriole diameter affect GFR?

Answer 10

Constriction of the efferent arteriole increases GFR by increasing pressure within the glomerulus.

Question 11

What is the role of the juxtaglomerular apparatus in regulating GFR?

Answer 11

The juxtaglomerular apparatus regulates GFR by controlling renin release and thus affecting arteriole diameter and blood pressure.

Question 12

How does the renin-angiotensin-aldosterone system (RAAS) influence GFR?

Answer 12

The RAAS system increases GFR by constricting the efferent arteriole and increasing systemic blood pressure.

Question 13

What is the effect of sympathetic nervous system activation on GFR?

Answer 13

Activation of the sympathetic nervous system decreases GFR by constricting afferent arterioles and reducing renal blood flow.

Question 14

How does the filtration coefficient (Kf) impact GFR?

Answer 14

The filtration coefficient (Kf) affects GFR by determining the permeability and surface area available for filtration.

Question 15

What is the role of mesangial cells in regulating GFR?

Answer 15

Mesangial cells regulate GFR by contracting or relaxing to alter the surface area available for filtration.

Question 16

How do plasma protein levels affect GFR?

Answer 16

Low plasma protein levels increase GFR by reducing colloid osmotic pressure in the glomerular capillaries.

Question 17

What is the relationship between GFR and renal plasma flow (RPF)?

Answer 17

GFR is directly proportional to renal plasma flow (RPF); increased RPF generally increases GFR.

Question 18

How does diabetes mellitus affect GFR?

Answer 18

Diabetes mellitus can initially increase GFR but may lead to decreased GFR over time due to kidney damage.

Question 19

How does hypertension influence GFR?

Answer 19

Hypertension can increase GFR initially but may cause damage that leads to decreased GFR over time.

Question 20

What is the effect of dehydration on GFR?

Answer 20

Dehydration decreases GFR due to reduced plasma volume and renal blood flow.

Question 21

How does aging impact GFR?

Answer 21

Aging generally decreases GFR due to a reduction in the number of functional nephrons.

Question 22

How does acute kidney injury (AKI) affect GFR?

Answer 22

Acute kidney injury (AKI) decreases GFR due to sudden loss of kidney function.

Question 23

What is the impact of chronic kidney disease (CKD) on GFR?

Answer 23

Chronic kidney disease (CKD) leads to a progressive decline in GFR over time.

Question 24

How do diuretics affect GFR?

Answer 24

Diuretics can affect GFR by altering plasma volume and renal blood flow.

Question 25

What is the role of natriuretic peptides in regulating GFR?

Answer 25

Natriuretic peptides increase GFR by dilating afferent arterioles and constricting efferent arterioles.

Question 26

How do nonsteroidal anti-inflammatory drugs (NSAIDs) influence GFR?

Answer 26

NSAIDs decrease GFR by inhibiting the production of prostaglandins, which dilate the afferent arteriole.

Question 27

What is the significance of creatinine clearance in estimating GFR?

Answer 27

Creatinine clearance is used to estimate GFR because creatinine is freely filtered and only minimally secreted by the kidneys.

Question 28

How does proteinuria relate to changes in GFR?

Answer 28

Proteinuria indicates damage to the glomerular filtration barrier, which can lead to changes in GFR.

Question 29

What are the implications of reduced GFR on electrolyte balance?

Answer 29

Reduced GFR can lead to imbalances in electrolytes such as sodium, potassium, and phosphate.

Question 30

How do changes in GFR affect the excretion of waste products like urea and creatinine?

Answer 30

Decreased GFR reduces the excretion of waste products like urea and creatinine, leading to their accumulation in the blood.