In some developing tissues, a mass of identical cells somehow differentiates into many types.The mechanism behind this process appears to have evolved early on, and is highly conserved.contains about a million pumps-each one is a slight bump on the cell membrane-and every pump can swap about 200 sodium ions for 130 potassium ions every second. The journal Science gives a figure of 100,000,000,000,000-equivalent to the number of stars in hundreds of Milky Way galaxies. It takes less space than an electrical synapse, which explains why the human brain has so many synapses. Note: The chemical synapse has a further advantage.Each neural impulse is transformed along the way, and nowhere else than at the synapses. They are, to complete this analogy, a carpenter’s kit, with screwdrivers, pliers, pincers, mallets-and hammers. . . They are not just hammers hitting the next nail, either more frequently or less so. they must be capable of passing on much more subtle information than yes or no. Neurons do not just fire and not fire.Meg Rosoff, World Book Night: Meg Rosoff on Mal Peet, The Telegraph.When you read a book, the neurons in your brain fire overtime, deciding what the characters are wearing, how they're standing, and what it feels like the first time they kiss.Charles Krauthammer, Interview Charles Krauthammer, Public Broadcasting Service, 29 January 2009.And if you're not struck by the mystery, I think you haven't thought about it. And how do you get from neurons shooting around in the brain to the thought that pops up in your head and mine? There's something deeply mysterious about that. Actually, their substrates are the inanimate. Life and consciousness are the two great mysteries.An illustration I use to get people to understand it is this: I'll ask major corporate audiences: Why don't you just take all your traditional beliefs about organizations, and apply them to the neurons in your brain?.David Eagleman, Philip Zimbardo et al., The Time Cure: Overcoming PTSD with the New Psychology of Time Perspective Therapy, Wiley, 2 October 2012, p.Each one of these cells is as complicated as a city. Your brain is built of cells called neurons and glia - hundreds of billions of them.Kripal, Comparing Religions, Wiley, 15 January 2014, p. Given the billions of neurons, this means there are as many connections in a single cubic centimeter of brain tissue as there are stars in the Milky Way galaxy. A typical neuron makes about ten thousand connections to neighboring neurons. Forge Public-Private Partnership to Draw Brain Activity Map?, pbs.org. Each one of those has about 10,000 connections. To a certain degree, we have read the letters of the human genome. We know how the heart pumps and how the kidney does what it does. We have learned a lot about other human organs.
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