Functions of The Nervous System | 9-1 GCSE Science Biology | OCR, AQA, Edexcel

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They key points covered in this video include:
1. Function of the nervous system
2. Structure of the nervous system
3. Coordinating a response
Function of the Nervous System
All organisms must respond to stimuli (changes in the environment). e.g. Changes in temperature. e.g. Start of an exam. Multicellular organisms need communication between cells/tissues/organs/systems. The human nervous system is an important part of how the body: Receives information from its surroundings (detects a stimulus). Processes this information and triggers an appropriate response. Communicates with itself to coordinate responses. All the neurones (nerve cells) in your body make up the nervous system. Nerves are simply bundles of neurones. Information is sent along neurones as electrical impulses (signals).
Structure of the Nervous System
Receptor cells are cells found in your sense organs. There are many different types of receptor cells which detect different stimuli, examples include: Light receptors in the retina of the eye which detect light stimuli. Taste receptors in the tongue which detect chemical stimuli. Pressure and temperature receptors in skin detect pressure and heat, respectively. Pain receptors in skin detect excess pressure or heat. Olfactory (smell) receptors and taste receptors in the nose detect chemical stimuli. They change signals from the environment (stimuli) into electrical signals which travel along neurones to the central nervous system (CNS). In vertebrates (animals with backbones) the CNS consists of the brain and spinal cord only. SENSORY neurones carry information from receptors in the sense organs as electrical impulses to the central nervous system (CNS). RELAY neurones are only found in the CNS - they carry electrical impulses from sensory neurones to motor neurones. MOTOR neurones carry electrical impulses from the CNS to effectors and coordinate the responses. Effectors may be muscles contracting or glands secreting hormones.
Coordinating a Response
This flow diagram is a very simple representation of your nervous system. In reality, the nervous system is made up of intricate and very complex networks of neurones. The CNS receives vast amounts of information from many sensory neurones simultaneously. Links to many neurones in different parts of your nervous system enable you to coordinate responses to bring about an appropriate action.
Summary
1. The nervous system enables the body to detect stimuli and to coordinate responses
2. Sensory neurones transfer information from receptors to the central nervous system (CNS)
3. The brain and spinal cord make up the CNS
4. Relay neurones transfer information from sensory neurones to motor neurones
5. Motor neurones transfer information to effectors which enable a response
6. The nervous system is a complex system because neurones have many links and go to all parts of the body
7. This enables us to coordinate different parts of the body to produce the appropriate response

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