• Question: how does the brain and heart work ?

    Asked by 101owen101 to Jonathan, Samantha, Sam on 5 Jul 2012.
    • Photo: Jonathan Kay

      Jonathan Kay answered on 5 Jul 2012:


      The heart is a muscle which pumps blood round the body and through the lungs. It varies how fast it pumps and how much blood it pumps according to what your body needs at the time. This is why your pulse rate increases when you run. Discovering how blood circulates was one of the greatest scientific breakthroughs ever. It has some other functions such as producing hormones.

      The brain is much more complicated than the heart. Some scientists say the human brain is the most complicated thing in the universe. A lot of it is built out of nerves like the nerves in your arms and legs but there are lots of other types of cells as well.

      Your brain controls your body movements and receives signals from your eyes, ears, nose, skin etc. We’re getting to know a lot more about how those work. But it’s also the organ that does thinking. We are nowhere near a good explanation of how that works. We don’t even know what a good theory of thinking would look like.

    • Photo: Sam Chilka

      Sam Chilka answered on 5 Jul 2012:


      Jonathan’s answer is really good. It’s interesting that there is still so much we still don’t know about the heart and brain. For example, we still don’t know how to properly “fix” hearts after a heart attack. And as Jonathan says, we don’t know how the brain makes it possible for us to think or have emotions. Right now I don’t know if we will ever know how thinking or emotions work.

    • Photo: Samantha Weaver

      Samantha Weaver answered on 6 Jul 2012:


      Here’s a different though for you – can your heart work without your brain?

      Your heart is able to beat on its own at around 50 beats per minute, because of the electrical impulses which are generated by the heart muscle. But without a brain you would not be able to live.
      The brain stem uses the autonomic nerves to control heart rate, and without those the heart rate would not be able to beat as fast as it needs to, to be able to survive.

      Some infants are born with anencephaly (where most of the brain is missing) but if the infant with anencephaly is born alive, the brain stem is present. Such infants usually die within hours or days of birth.

      People can be ‘brain dead’ but their heart is functioning because they’re connected to life support, and they have brain stem function (which controls heart rate). In these cases a patient can be considered ‘brain dead’ because all higher functions of the brain have ceased, and often even with support present the body will cease to function within hours or days.

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