1.2 Overview of the Nervous System

Nervous system

The body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems

Central nervous system (CNS)

The brain and spinal cord

Peripheral nervous system (PNS)

The sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body

Nerves

Bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sensory organs

Sensory neurons

Neurons that carry incoming information from the body’s tissues and sensory receptors to the brain and spinal cord

Motor neurons

Neurons that carry outgoing information from the brain and spinal cord to the muscles and gland

Interneurons

Neurons within the brain and spinal cord; they communicate internally and process information between the sensory inputs and motor outputs

Somatic nervous system

The division of the peripheral nervous system that controls the body’s skeletal muscles; also called the skeletal nervous system

Autonomic nervous system (ANS)

The part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart); its sympathetic division arouses; its parasympathetic division calms

Sympathetic nervous system

The division of the autonomic nervous system that arouses the body, mobilizing its energy

Parasympathetic nervous system

The division of the autonomic nervous system that calms the body, conserving its energy

Reflexes

A simple, automatic response to a sensory stimulus, such as the knee-jerk response