• Question: How does the body know what to do when breathing, blinking and moving?

    Asked by ejrw to Adam, Catherine, Karen, Leila, Nazim on 13 Mar 2012.
    • Photo: Nazim Bharmal

      Nazim Bharmal answered on 10 Mar 2012:

      We can’t control some things (like our heartbeat) but we can stop other things that happen automatically (like breathing) so our brains have ‘software’ (like a computer) that we can use to change how we work. But like a computer, we don’t have ‘permission’ to change everything (which is probably a good thing, as its taken a long time to get the ‘software’ in our brains working right.)

    • Photo: Adam Stevens

      Adam Stevens answered on 10 Mar 2012:

      Our nervous system is really complicated. Part of it works without any real input from our brains, which is leftover from our evolution from more primitive lifeforms (we call them reptilian responses).

      Things like breathing and blinking are controlled automatically by this part of the nervous system, so they can in fact work without our brains (in some cases).

      There are some people that learn to control these automatic responses to a certain extent. For example, freedivers can overcome the automatic urge to breathe by doing certain exercises so that they can hold their breath for a long time (sometimes like 10 minutes!).

      There are also things that can interrupt the automatic control. Sometimes the brain can send conflicting messages. When I’m really tired my left eye twitches a lot which is really annoying!

    • Photo: Leila Battison

      Leila Battison answered on 10 Mar 2012:

      Your brain allows you to control what you do, but another part of your nervous system, your spinal cord, deals with ‘involunatary actions’ like the reflex when you hit your knee and it makes your leg kick out.

      The brain gets messages from your senses inside and outside the body, like ‘my eyes are drying out and are sore’, or ‘my blood hasn’t got enough oxygen’, or ‘my hand is in some fire and is getting all crispy’, and it is best if it fixes the problem directly rather than stopping you thinking about whatever you are doing to ask you to make a decision. That’s why we blink and breathe without thinking, and move our hand out of fire before getting crispy.

      You can concentrate really hard on overriding these natural reactions for a while, letting you win a staring competition, or stay underwater for a long time, or get crispy hand bacon if you want… but the body will kick in before you do yourself any fatal harm.

      Some things you can’t affect at all, like the constant beat of your heart, which is controlled without interaction from the brain (although you can speed it up or slow it down).

    • Photo: Karen Masters

      Karen Masters answered on 13 Mar 2012:

      I don’t know much about biology. I last took it at GCSE level. My Mum was an A-level Biology teacher, so I could ask her if you like! 😉

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