The Nervous System

The Nervous System

• Parts of the nervous system include: the Central Nervous System (CNS), sensory neurones, motor neurones and effectors.
• In vertebrates, the central nervous system consists only of the brain and spinal cord. However, in mammals the CNS is connected to the body by sensory and motor neurones.
• Sensory neurones are the neurones that carry information as electrical impulses from the receptors to the CNS.
• Motor neurones are the neurones that carry electrical impulses from the CNS to the effectors.
• Effectors include all the muscles and glands that respond to nervous impulses.
• Receptors are the cells that detect stimuli.
• There are many kinds of receptors, such as taste receptors on the tongue and sound receptors in the ear.
• Receptors can form parts of larger organs e.g. the retina of the eye is covered in light receptor cells.
• Effectors respond to nervous impulses and bring about a change.
• Muscles and glands are known as effectors- they respond in different ways. Muscles contract in response to a nervous impulse, whereas glands secrete hormones.
• The CNS is a co-ordination centre- it receives information from the receptors and then co-ordinates a response. The response is carried out by the effectors.
• For example, a small bird is eating some seed when it sees a cat coming towards it in the corner of…