Divisions of the Nervous System
Central Nervous System
The Central Nervous System (CNS) is one of the major divisions of the nervous system, consisting of the brain and spinal cord.
Peripheral Nervous System
The Peripheral Nervous System (PNS) includes nerves that run throughout the body and connects the CNS to limbs and organs. It has subdivisions: the somatic and autonomic nervous systems.
Somatic Nervous System
The Somatic Nervous System (SNS) carries sensory signals from the body to the CNS and motor signals from the CNS to skeletal muscles; it is associated with voluntary movement.
Autonomic Nervous System
The Autonomic Nervous System (ANS) regulates the internal environment and operates largely outside conscious control. It carries signals between internal organs and the CNS and has two subdivisions: sympathetic and parasympathetic.
Sympathetic Nervous System
The Sympathetic Nervous System mobilizes energy resources for activity (fight or flight), typically increasing heart rate and blood pressure and activating sweat glands.
Parasympathetic Nervous System
The Parasympathetic Nervous System conserves energy and supports rest and digestion, including digestion, salivation, and slowing the heart rate.