Problem 1: Vasoconstriction of either the afferent or the efferent arteriole increases resistance within the capillary plexus. Vasoconstriction of the afferent arteriole increases the resistance within the circuit, thus decreasing renal blood flow. The efferent arteriole follows in series (returning to our electrical analysis). For circuits, in which resistors are arranged in series, the resistance is additive. Why then does the vasoconstriction of the efferent arteriole not lead to decreased renal perfusion?
Problem 2: In the setting of renal injury, in which some but not all of the glomerular capillary loops are injured, how might the relationship between renal bloods flow, capillary pressure, and glomertilar filtration change?