A 20 year old male patient came with the complaint of a decrease in the urinary output to about 400ml/day. Both RBF and GFR were decreased. Which of the following causes a decrease in both RBF and GFR?
Dilation of efferent aeriole
Dilation of afferent aeriole
Only afferent aeriolar constriction
Only efferent aeriolar constriction
Constriction of either the afferent or efferent aeriole increases resistance, and according to Equation Q = DP/R, an increase in resistance (R) decreases flow (Q) (i.e., RBF). Dilation of either the afferent or efferent aeriole increases flow (i.e., RBF). Constriction of the afferent aeriole (A) decreases P GC because less of the aerial pressure is transmitted to the glomerulus, thereby reducing GFR. Dilation of the afferent aeriole increases P GC because more of the aerial pressure is transmitted to the glomerulus, thereby increasing GFR.Reference: Berne and Levy Medical Physiology; 6th edition; Page no: 574
Renal physiology