Nervous system

The human nervous system consists of:

• the central nervous system (CNS) – the brain and spinal cord
• the peripheral nervous system – nerve cells that carry information to or from the CNS

Nerve cells

Nerve cells are also called neurones. They are adapted to carry electrical impulses from one place to another:

• they have a long fibre (axon) which is insulated by a fatty sheath
• they have tiny branches (dendrons) which branch further as dendrites at each end

Receptors to effectors

The diagram summarises how information flows from receptors to effectors in the nervous system.

Receptors

Receptors are groups of specialised cells. They can detect a change in the environment (stimulus) and produce electrical impulses in response. Sense organs contain groups of receptors that respond to specific stimuli.

Sense organStimulus Skin Touch, temperature Tongue Chemicals (in food and drink, for example) Nose Chemicals (in the air, for example) Eye Light Ear Sound

Effectors

Effectors are parts of the body - such as muscles and glands - that produce a response…