Final answer:
The correct statement about pelvic splanchnic nerves is that they are involved in controlling pelvic organs, as part of the parasympathetic nervous system.
Step-by-step explanation:
The True Statement about Pelvic Splanchnic Nerves
The correct answer to which statement is true for pelvic splanchnic nerves is d) They are involved in controlling pelvic organs. Contrary to the other options, pelvic splanchnic nerves do not originate from the brainstem, they do not innervate structures in the chest, and they are not part of the sympathetic nervous system. Instead, they arise from the sacral spinal nerves and form part of the parasympathetic nervous system. These nerves project to terminal ganglia in the lower abdominal and pelvic cavities to help regulate homeostatic mechanisms, including control over functions such as bladder contraction and sexual arousal.
The nervous system that directly controls the digestive system is, in general, the parasympathetic nervous system, which opposes the sympathetic nervous system's fight-or-flight response by promoting restful and digestive activities.