noun Anatomy, Zoology.
- the system of nerves and nerve centers in an animal or human, including the brain, spinal cord, nerves, and ganglia.
- a particular part of this system.
- the sensory and control apparatus of all multicellular animals above the level of sponges, consisting of a network of nerve cellsSee neurone See also central nervous system
- The system of cells, tissues, and organs that regulates the body’s responses to internal and external stimuli. In vertebrates it consists of the brain, spinal cord, nerves, ganglia, and parts of the receptor and effector organs.
- The system of neurons and tissues that regulates the actions and responses of vertebrates and many invertebrates. The nervous system of vertebrates is a complex information-processing system that consists mainly of the brain, spinal cord, and peripheral and autonomic nerves. It receives chemical information from hormones in the circulating blood and can also regulate secretions of the endocrine system by the action of neurohormones. The nervous systems of invertebrates vary from a simple network of nerves to a complex nerve network under the control of a primitive brain. See also autonomic nervous system central nervous system peripheral nervous system.
The system in the body that controls internal functions of the body and receives, interprets, and responds to stimuli. The nervous system is made up of the brain, the spinal cord, the nerves, and the sense organs, such as the eye and ear.