How well do you know your body?

Children can rewire faster than grown-ups, but adults have developed the bit of the brain that allows them to concentrate, delay pleasure and focus on a goal.

It’s a nice lesson that grown-ups are still able to rewire new bits of the brain. They’re not able to do it as quickly as children but we have other learning advantages – so the fact is you can teach an old dog new tricks. It’s believed disgust is an emotion that binds our society together. A bit like fear, it’s controlled by a very ancient portion of the brain – but we can overcome it by using our grey matter, which is obviously why some societies differ on what they find disgusting.

What does bravery look like in the brain?

When you see something frightening, your brain has a rather ancient reptilian bit – a set of neurons called your amygdala. And before you’re consciously aware of it, this will be priming your body for its fight or flight response. We’re able to overcome our fears because we have this complicated cortex on the surface of the brain that closes off the amygdala. It’s like one part of your brain telling another part to calm down. The good news is you can train your brain to shut down the amygdala.

Are tears of sadness different to tears of joy?

You leak tear fluid over the surface of your eyeball all the time.

This fluid contains an immune system and nutrients. It cleans the surface of the eye and lubricates it. I think tears of laughter are mechanical because when you crease up your face, you’re squeezing more tears out.

Sad tears probably contain some hormones that are different to other kinds of tears. It’s hard to explain in evolutionary terms why we do that, but it seems to be important for humans to have ways of communication that we can’t fake. We have thousands of species of bacteria living on our skin with up to a million individual bacteria per square cm.

One study identified over 1,000 bacterial species previously unknown to science simply by swabbing people’s belly buttons.

A deficiency in our digestive tract, where we have trillions of bacteria, can have a huge impact on the workings of our body – fevers, obesity, high blood pressure and heart disease can all be attributed to it.

This deficiency can even affect our mood. It slows our bod allows old age and it trillion body w replace

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