What is a Reflex Arc | Physiology | Biology | FuseSchool

What is a Reflex Arc | Physiology | Biology | FuseSchool

Our bodies have a system in place which enables us to react really quickly, called reflex reactions.

Reflex reactions are immediate, unconscious responses to a stimulus that provides us with protection and aids survival. When your safety demands a quick response, the signals may bypass the brain and be acted upon as soon as they reach the spinal cord. These shorter pathways are called reflex arcs.

Reflex arcs are in-built, or innate, behaviours. And we all behave in the same way. Even though the brain is bypassed for the immediate response, the nerve message is still passed onto the brain so that you can think about whether any further action is needed.

So the pathway has been cut down by speeding up the central nervous system aspect – the message reaches the spinal cord and heads straight back out down motor neurons to produce a response.

We cut out the central nervous system to reduce the pathway from stimulus → receptor → sensory neurone → central nervous system → motor neurone → effector pathway to stimulus → receptor → sensory neurone → motor neurone → effector pathway.

There are 2 types of reflex:
1) Simple reflexes like we have seen already. Your brain is not aware of the initial response and are there to aid your survival.
2) Conditioned reflexes. These involve prior thought or learning and your body responds subconsciously because of this prior learning… Pavlov’s dogs is an example of conditioned reflexes. During his experiments, Pavlov rang a bell immediately before feeding the dogs. He found that after a while, the dogs would produce saliva just on hearing the bell without food being provided. Pavlov called this a learnt response, which does not involve conscious thought and is conditioned reflex.

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