Key Terms in the Nervous System
- The human nervous system consists of the central and peripheral nervous system as seen in the image below
- The nervous system enables humans to react to their surroundings and to coordinate their behaviour
- Information is sent through the nervous system as electrical impulses – electrical signals that pass along nerve cells known as neurones
- A bundle of neurones is known as a nerve
The nervous system is made up of the CNS and the PNS
- There are many key terms associated with the nervous system topic
- Some of the most important terms and their definitions include
- Stimulus: A detectable change in the internal or external environment of an organism e.g. light, sound or temperature
- Receptor: A cell or organ which detects a stimulus
- Neurone: A nerve cell, specially adapted to carry electrical charges, called nerve impulses from one part of the body to another
- Sensory neurone: A neurone which carries nerve impulses from receptors to the central nervous system
- Motor neurone: A neurone which carries nerve impulses from the central nervous system to effectors
- Relay neurone: A neurone that acts as a coordinator, transmitting impulses from the sensory to the motor neurone in the spinal cord
- Effector: A cell, tissue, organ or organ system that responds to a stimulus
- Voluntary response: A nerve pathway which produces a conscious response to a stimulus
- Reflex response: A nerve pathway which produces an automatic response to a stimulus
- Synapse: A gap between two neurones
- Axon: A single long fibre within a neurone which carries a nervous impulse away from the cell body
- Electrical impulse: A signal which is passed through the nervous system as electrical charge to instigate a response
- Central nervous system (CNS) – The part of the nervous system which includes brain and spinal cord
- Peripheral nervous system (PNS) – All of the nerves in the body which extend from the CNS
