Which factor would increase the glomerular filtration rate?

• A. Constriction of the afferent arteriole
• B. Decreased permeability of the glomerular membrane
• C. Increased plasma protein concentration
• D. Increased blood pressure in the glomerular capillaries

Answer: (D)

Verified step by step guidance

1. Understand the concept of glomerular filtration rate (GFR), which is the rate at which the kidneys filter blood, removing waste and excess substances.
2. Recognize that GFR is influenced by several factors, including blood pressure in the glomerular capillaries, permeability of the glomerular membrane, and plasma protein concentration.
3. Consider how blood pressure affects GFR: Increased blood pressure in the glomerular capillaries generally leads to an increase in GFR because it forces more fluid through the filtration membrane.
4. Analyze the effect of afferent arteriole constriction: Constriction reduces blood flow into the glomerulus, decreasing pressure and thus reducing GFR.
5. Evaluate the impact of plasma protein concentration: Increased plasma protein concentration raises the osmotic pressure, which can decrease GFR by pulling water back into the capillaries, opposing filtration.