The Spark of Life: Electricity in the Human Body in Science and Inquiry

Oct 07, 2015 Charlene rated it it was amazing

Shelves: neuroscience, biology, favorites

Do you thirst for in depth explanations about how your body works? If so, read this book.

We know well how an electric cord works when plugged into an outlet and a switch is flipped. But what plugs you in? What sort of current does the human body use to breathe, eat, move, have sex, read a book, or even to sit and think? Ashcroft goes into great detail about the currents that make you an active system. Instead of an outlet in a wall, the currents inside humans, and other animals, are generated b Do you thirst for in depth explanations about how your body works? If so, read this book.

We know well how an electric cord works when plugged into an outlet and a switch is flipped. But what plugs you in? What sort of current does the human body use to breathe, eat, move, have sex, read a book, or even to sit and think? Ashcroft goes into great detail about the currents that make you an active system. Instead of an outlet in a wall, the currents inside humans, and other animals, are generated by tiny ions that flow through ion channels. This is the thermodynamics of life at its best. (Though she never actually mentions thermodynamics).

Ashcroft included all the best concepts learned in classes such as intro to neuroscience, intermediate biochen, and the lighter aspects of neurocellular biochem and neurophysics. For example, she does an amazing job of explaining how the inside of the cell has a high potassium concentration, while the outside of the cell has high sodium concentration. This creates a gradient that allows the current of bio-electricity to continually flow through the body. Having done such a great job simplifying that for the reader, Ashcroft was perfectly positioned to explain how that current is turned into axon potentials, which govern every process in which humans engage. She really brought the magic of cells and ion channels alive.

Energy flow in the human body, and in all cells, is one of my favorite topics to read about and think about. It's hard to find a book this detailed. Some authors choose this subject to write about, but their numbers are surprisingly few. Nick Lane's Life ascending and Power, Sex, and Suicide were extremely satisfying for me but not as relatable as Ashcroft's writing.

I have to say, I felt entirely perplexed that Ashcroft believes that life probably began in a tiny little pond. I have no idea how she can believe this. It's entirely possible Nick Lane, along with Martin and Russell, are wrong in their hypothesis that life originated at the hydrothermal vents. But if life did not originate there, it seems necessary -- not just likely-- that it arose somewhere that provided the energy needed to create and maintain enzymes that make cellular products. This aspect of the book will bother me continuously until I understand how she can account for the needed energy of the enzymes. She is far more knowledgeable than I am, as is Nick Lane. So I am sure there is something I missing about her hypothesis. But it's driving me crazy, and she did not write about where the energy would have come from in her scenario.

From page one, I fell in love with this book. It was quickly clear that this was the biochem (ion channel) book I have been looking for all my life! I remember learning about how our brain cells work to help us see, smell, taste, hear, see, and touch our world. My mind was completely blown away, because I simply could not believe nature could be that beautiful and that brilliant. But it is, and Ashcroft did a great job of conveying how much of that brilliance is due to ion channels. Ashcroft herself states that "This is a book about ion channels." Indeed it is. For it is the ion channel that takes every experience you will ever have with the world around you and detects, transmits, and processes every last bit of it so that you can even call it an experience.

It was clear to me that Ashcroft is in awe of the body, which has as many cells as the galaxy has stars, and the brains inside those bodies. She wrote about action potentials, resting potentials on each side of the membrane and why that matters (and how that makes you able to function and live in the world). Despite having read so much similar material for years, Ashcroft made my dopamine neurons go crazy during each page because she explains it all so tremendously well. I would have been happy with a book 4 times as long!

Her coverage of cell suicide was crazy good; so good in fact, I kept saying, "How can this book even exist?" (I *really* love cells). Cells kill themselves all the time for the good of the system (the animal body). For example, if cells did not undergo apoptosis during our fetal development, we would all have webbed fingers and toes. If cells didn't undergo apoptosis after we were born, our brains simply could not function. After she provided examples of apoptosis in the human animal, she wrote about the actual process of apoptosis in which the cell takes over the mitochondria and directs it to kill itself. (so good!)

She gave a beautiful description of photosynthesis, but it is likely not what you have heard before. Yes, she covers the basics, but she tells the story of photosynthesis from the perspective of the ion channel.

The last part of the book discussed what happens when ion channels work or do not work correctly. The result is a sensual experience of the world or an inability to sense the world. This section came alive with great examples, including somme little known trivia about Monet.

Thank you Frances Ashcroft for writing a book that makes me feel like I was lucky enough to hop on a plane, fly over to England, take a seat in your lecture hall at Oxford University, and learn the intricate details about the energetics of animal systems -- and not to have to do problem sets or take exams. The only thing that would make me happier would be for Ashcroft to put her lectures in a public domain so I could watch every last one of them. ...more

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