Physiology What is the effect of constriction of efferent aeriole and dilatation of afferent aeriole on glomerular filtration rate? A Increases GFR B Decreases GFR C No change to GFR D First increase then decreases GFR 💡 Explanation What is the effect of constriction of efferent aeriole and dilatation of afferent aeriole on glomerular filtration rate? ✓ Correct Answer: A. Increases GFR