Difference between revisions of "Reflex Arc"
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===About the Reflex Arc=== | ===About the Reflex Arc=== | ||
| − | : Sometimes a change in the environment is so dangerous it would cause more damage to have to think about it before reacting to it. This is the case for very high [[temperature]]s. If the [[skin]] begins to burn this will cause more damage the longer it takes to react. [[Animal]]s have [[evolution|evolved]] | + | : Sometimes a change in the environment is so dangerous it would cause more damage to have to think about it before reacting to it. This is the case for very high [[temperature]]s. If the [[skin]] begins to burn this will cause more damage the longer it takes to react. [[Animal]]s have [[evolution|evolved]] reflex reactions to react quickly to prevent unnecessary damage. |
: [[Reflex Reaction|Reflex reactions]] take place when an [[Impulse (Biology)|impulse]] is sent along the '''reflex arc'''. | : [[Reflex Reaction|Reflex reactions]] take place when an [[Impulse (Biology)|impulse]] is sent along the '''reflex arc'''. | ||
: The [[Impulse (Biology)|impulse]] in the '''reflex arc''' does not pass to the [[brain]] to be processed. It is sent to the [[Spinal Cord|spinal cord]] then to an [[effector]]. This provides a shorter path for the [[Impulse (Biology)|impulse]] so results in a shorter reaction time. | : The [[Impulse (Biology)|impulse]] in the '''reflex arc''' does not pass to the [[brain]] to be processed. It is sent to the [[Spinal Cord|spinal cord]] then to an [[effector]]. This provides a shorter path for the [[Impulse (Biology)|impulse]] so results in a shorter reaction time. | ||
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#[[Motor Neuron]] - The [[Impulse (Biology)|impulse]] is [[transmit]]ted from the [[Spinal Cord|spinal cord]] to an [[effector]]. | #[[Motor Neuron]] - The [[Impulse (Biology)|impulse]] is [[transmit]]ted from the [[Spinal Cord|spinal cord]] to an [[effector]]. | ||
#[[Effector]] - A [[muscle]] receives the [[Impulse (Biology)|impulse]] form the [[Motor Neuron|motor neuron]]. | #[[Effector]] - A [[muscle]] receives the [[Impulse (Biology)|impulse]] form the [[Motor Neuron|motor neuron]]. | ||
| − | # | + | #Action - The [[muscle]] contracts causing part of the body to move uncontrollably. |
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Revision as of 21:14, 7 April 2019
Key Stage 4
Meaning
The reflex arc is the path taken by an electrical impulse to cause an automatic reflex reaction.
About the Reflex Arc
- Sometimes a change in the environment is so dangerous it would cause more damage to have to think about it before reacting to it. This is the case for very high temperatures. If the skin begins to burn this will cause more damage the longer it takes to react. Animals have evolved reflex reactions to react quickly to prevent unnecessary damage.
- Reflex reactions take place when an impulse is sent along the reflex arc.
- The impulse in the reflex arc does not pass to the brain to be processed. It is sent to the spinal cord then to an effector. This provides a shorter path for the impulse so results in a shorter reaction time.
The reflex arc can be described in several stages:
- Stimulus - A change to the external environment.
- Receptor Cell - A specialised cell detects the change in the environment and produces an electrical impulse.
- Sensory Neuron - The impulse is transmitted to the spinal cord.
- Relay Neuron - The impulse is relayed from the sensory neuron to a motor neuron.
- Motor Neuron - The impulse is transmitted from the spinal cord to an effector.
- Effector - A muscle receives the impulse form the motor neuron.
- Action - The muscle contracts causing part of the body to move uncontrollably.
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| A diagram showing the reflex arc. |