• Question: why are reflex neurons so fast at reacting?

    Asked by anon-241419 to Ross, Natalia, Martin, Gabriela, Ellie, Chukwuka on 16 Mar 2020.
    • Photo: Martin Johnsson

      Martin Johnsson answered on 16 Mar 2020:

      The reason reflexes are so fast has to do with the way the neurons fit together.

      The pathways of neurons behind reflexes consist only of a few neurons: in the simplest case one that senses the input, and one that signals the muscle to contract. This is faster than having to go through a lot of neurons and more processing.

      To take the knee jerk reflex as an example: when your knee is tapped, the signal goes from the knee into the spinal cord, and then out again to the muscles in your leg. The brain does not have to be involved.

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