Final answer:
The autonomic nervous system is a division of the PNS that regulates involuntary bodily functions, differentiated into sympathetic and parasympathetic divisions for stress response and routine 'housekeeping' functions, respectively.
Step-by-step explanation:
The autonomic nervous system is a division of the peripheral nervous system (PNS) that controls involuntary activities of the body, which are not under our conscious control. It is responsible for the regulation of our internal organs and glands and can be further divided into the sympathetic and parasympathetic nervous system. The sympathetic division prepares the body for stress-related activities, often referred to as the fight-or-flight response, while the parasympathetic division promotes the rest-and-digest functions during calmer moments.
The autonomic control is based on visceral reflexes, which include both afferent (sensory) and efferent (motor) components. The efferent branch is characterized by a two-neuron pathway, where the preganglionic neuron in the CNS synapses with a postganglionic neuron that then innervates the target organ. Coordination of this system requires integration with higher brain structures, like the hypothalamus, to maintain homeostasis within the body. Some examples of autonomic control include the adjustment of heart rate, digestion, and respiratory rate.