Imagine all your tiny cells are microscopic cogs inside a giant machine. Now consider the fact there are between 75-100 trillion of those cells furiously working around the clock inside you at all times and you'll start to get the picture of what an amazing machine the human body truly is. You can think of them as little nanobots, or molecular-sized warriors capable of almost anything—thwarting off unwanted intruders, fighting viruses and guiding your body through changes. Composed of millions of even smaller atoms, cells are the building blocks of all life forms. Each cell is programmed to perform a specific bodily function within a certain lifespan. From regenerating damaged skin, to providing quick energy to combating infections and diseases, cells are jacks of all trades and are necessary to regulate normal human body systems. Every part of your body consists of cells: bone tissue, neurons in the brain, organs and even your fingernails are all examples living, growing cell groups. Using scanning electron micrographs (SEM) we're able to magnify cells—which range in size from 1-100 micrometers—into fully detailed and vibrant images that tell the story of our bodies, biology and human evolution back thousands of years. In fact, prokaryotic cells, which are single-celled basic organisms, are the most primitive form of life on Earth and likely the first living thing we know of.
Not all cells are so simple. The largest known cells can weigh as much as a whopping three pounds and are found in the form of ostrich eggs. No matter the size, the power of human cells is immense and unrelenting—so you've got some pretty tough biological allies on your side. Check out this playlist to learn more about the amazing ways our cells go to work: cloning, regrowing limbs, saving lives and much more.