Divisions of the Nervous System

Autonomic Nervous System (ANS)

Regulates heart rate, breathing, blood pressure, digestion, hormone secretion, and other functions. The autonomic nervous system usually functions without conscious effort, which means that only a few of its responses, such as breathing, can also be controlled voluntarily. Two subdivisions, (Sympathetic and Parasympathetic).

Parasympathetic Division

Returns the body to a calmer, relaxed state and is involved in digestion.

Sympathetic Division

Triggered by threatening or challenging physical to psychological stimuli, increases physiological arousal and prepares the body of action.

Somatic Nervous System

Consists of a network of nerves that connect either to sensory receptors or to muscles that you can move voluntary, such as muscles in your limbs, back, neck, and chest. Nerves in the somatic nervous system usually contain two kinds of fibers. Afferent , or sensory, fibers carry information from sensory receptors in skin, muscles, and other organs to the spinal cord and brain. Efferent, or motor fibers carry information from there brain and spinal cord to the muscles.

Peripheral Nervous System (PNS)

Includes all of the nerves that extends from the spinal cord and carry messages to and from various muscles, glands, and sense organs located throughout the body. Two subdivisions, (somatic and autonomic).

Central Nervous System (CNS)

Made up of the brain and spinal cord. From the bottom of the brain emerges the spinal cord, which is made up of neurons and bundles of axons and dendrites that carry information back and forth between the brain and the body.