nerves and reflexes
- Created by: GraceYoung
- Created on: 29-08-18 15:22
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- nerves and reflexes
- stimuli are detected by sensory receptors that send impulses along sensory neurones to the central nervous system
- neurones are specialised cells that carry nervous impulses
- types of neurones
- sensory neurones carry impulses to the central nervous system
- motor neurones carry impulses from the central nervous system to effector organs
- relay neurones are found only in the central nervous system
- A long fibre (axon) which is insulated by a fatty (myelin) sheath. They are long so they can carry messages up and down the body.
- Tiny branches (dendrons) which branch further as dendrites at each end. These receive incoming impulses from other neurones.
- the coordination centre, such as the brain, spinal cord or pancreas, receive and process information from receptors around the body
- effectors bring about responses, which restore optimum levels, such as core body temperature and blood glucose levels
- effectors include muscles and glands so responses can include muscle contractions or hormone release
- the point where two neurones meet is called a synapse
- there is a small gap between the neurones
- the electrical nerve impulses can not be carried across the gap so the impulse is carried by neurotransmitters
- there is a small gap between the neurones
- receptors to effectors
- Receptor cells detect a change in the environmental (a stimulus) and start electrical signals along neurons. These move towards the central nervous system (CNS).
- Messages are then sent back along different neurones to muscles which contract or relax, and glands which secrete hormones. Muscles and glands are called effectors.
- Receptors are groups of specialised cells.
- They detect a change in the environment and stimulate electrical impulses in response.
- Effectors include muscles and glands. They produce a specific response to a detected stimulus.
- Receptor cells detect a change in the environmental (a stimulus) and start electrical signals along neurons. These move towards the central nervous system (CNS).
- the relax arc
- reflex arcs involve only three neurones and impulses pass to and from the spinal cord
- this provides a fast response that does not involve the brain
- relaxes help protect us from immediate harm such as eye blink relax which protects the eye if something comes close to it
- reflex arcs involve only three neurones and impulses pass to and from the spinal cord
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