This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Sympathectomy of the kidney results in which of the following responses? 
Select and explain. 
A. No change to the glomerular filtration rate, nor to the urine output, B. Decreased urine output, C. Reduction of glomerular filtration rate and decreased urinary output, D. Increased urine output
D: Increased urine output
Answer: D: Increased urine output 
Explanation: The kidney is innervated primarily by the sympathetic nervous system and as such, regulates the contraction of the smooth muscle surrounding the afferent and efferent aerioles of the glomerulus. Sympathetic stimulation to the efferent glomerular aerioles causes the constriction and increases the filtration rate, leading to an increase in urinary output. Similarly, with the loss of sympathetic innervation, such as due to sympathectomy of the kidney, relaxation of tone of the afferent aerioles occurs and the filtration rate increases which results in an increased urine output. Decreased urine output may result from the restriction of the afferent aerioles, leading to a decrease in glomerular filtration rate. Ref: Eaton D.C., Pooler J.P. (2009). Chapter 1. Renal Functions, Anatomy, and Basic Processes. In D.C. Eaton, J.P. Pooler (Eds), Vander's Renal Physiology, 7e.