Reflex action (& reflex arc) | Control & Coordination | Biology | Khan Academy

Khan Academy India - English2 minutes read

Various stimuli trigger involuntary reflex actions, such as moving away from heat or raising a leg, which do not require conscious decision-making and involve only three neurons and the spinal cord for immediate response. These reflex actions involve a sensory neuron detecting the stimulus, a relay neuron transferring the signal, and a motor neuron activating the muscle for action, bypassing the brain in a unique loop shape always connecting to the back of the spinal cord.

Insights

  • Reflex actions are automatic responses triggered by stimuli like heat or light, bypassing conscious thought and involving only three neurons and the spinal cord for immediate reaction.
  • The sensory neuron detects the stimulus, the relay neuron transfers the signal, and the motor neuron activates the muscle, showcasing a rapid and efficient reflex arc that prioritizes quick responses over conscious decision-making.

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Recent questions

  • What are reflex actions?

    Involuntary responses to stimuli, like sneezing or moving away.

  • How do reflex actions work?

    They involve three neurons and the spinal cord.

  • What triggers reflex actions?

    Changes in temperature, light, smell, and pressure.

  • Are reflex actions conscious decisions?

    No, they do not require conscious decision-making.

  • What is the role of sensory neurons in reflex arcs?

    They detect stimuli and connect to the spinal cord.

Related videos

Summary

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"Involuntary Reflex Actions: Immediate Responses to Stimuli"

  • In four videos, various stimuli trigger involuntary reflex actions: changes in temperature, light, smell, and pressure.
  • Reflex actions are automatic responses to stimuli, such as moving away from heat, sneezing, or raising a leg.
  • These responses are involuntary and do not require conscious decision-making, known as reflex actions.
  • The mechanism of a reflex action involves only three neurons and the spinal cord, bypassing the brain for immediate response.
  • The sensory neuron detects the stimulus, the relay neuron transfers the signal, and the motor neuron activates the muscle for action.
  • Reflex arcs consist of sensory, relay, and motor neurons, with sensory neurons having a unique loop shape and always connecting to the back of the spinal cord.
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