The Autonomic Nervous System, ANS, is the second off-shoot of the PNS. It specifically deals with involuntary functions such as, breathing, heartbeat, and digestion.
The Parasympathetic Nervous System is an off-shoot of the ANS. It specifically deals with the heart rate and intestinal functions.
The Sympathetic Nerbpus System is the second off-shoot of the ANS. It deals with the releasing of hormones causing "adrenaline rushes".