The tutor continues about the nervous system.

A reflex, like kicking out after a tap below the knee-cap or pulling the hand back from a hot stove, is a familiar idea. Most people understand “reflex” to mean “done automatically” or “done without thinking.”

From the point of view of Biology 12, reflex actions truly are done without thinking, because they are done without the brain’s consultation. The decision to withdraw the hand from the hot stove comes from the spine, rather than the brain. The brain is notified afterwards.

The mechanism “spine realizes danger, so spine sends message to muscle to elicit damage control”, is called a reflex arc. The advantage is that the reaction happens much faster than if the brain had to decide. Saving those precious milliseconds can (and definitely does, in many cases) prevent serious injury.

Source:

Mader, Sylvia S. Inquiry into Life, 9th Ed. Toronto: McGraw-Hill, 2000.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.