Reflex action

The idea

A reflex action is a sudden action in response to a change in the environment, done without thinking about it or feeling in control of the reaction.

A hot pan

Meena touches the hot handle of a pan. Her hand is back before she can even say ouch.

How did she move her hand so fast?

• She did not stop to think about it
• She first thought carefully about the burn and then decided
• She waited for a friend to tell her to move

Reflex or thought out

Sort each example into the right group.

Without thinking

In a reflex you do not stop to think. You also do not feel in control of the reaction. It is still a response to a change around you, such as a flame or a bus.

A reflex action is a sudden action in response to a change in the environment. We do it without thinking about it or feeling in control of the reaction.

Notes

A reflex action is a sudden action in response to a change in the environment, done without thinking about it or feeling in control of the reaction.

Check yourself

Which of these is a reflex action?

What is true of a reflex action?

Which one is NOT a reflex action?

• Moving a chair. We decide to move a chair, so it is a thought-out action.
• Pulling the hand back from a flame — correct. Yes!
• Writing in a notebook. We decide what to write, so it is thought out.
• It happens when we feel fully in control of the reaction. In a reflex we do not feel in control of the reaction.
• It has nothing to do with the environment. A reflex is a response to a change in the environment, such as a flame or a bus.
• It is a sudden response to a change in the environment — correct. Yes!
• Clapping at the end of a programme — correct. Yes!
• Jumping out of the way of a bus. The book gives this as a sudden action done without thinking.
• Change in the size of the pupil. The book gives this as a simple reflex action.