Cells and Tissues

Imagine this: if each cell in our body was represented by a one-meter step, we would have to circle the earth over one million times to account for all our cells. It seems absurd, but it’s true.   We are each composed of between 50 and 100 trillion cells! As I continue to report on my study of Human Anatomy and Physiology by Elaine Marieb, I move from chemistry to structural components. Cell theory was developed in the late 1800s and is based on four core elements: The cell is the basic unit of living organisms, Organisms depend on both individual and combined activities of its cells, The activities of cells are dictated by their shape and number of structures they contain, and Cells arise from other cells. Restated, our 50+ trillion cells are the body’s building blocks, they don’t stand alone, they look different and do different things, and they’re self perpetuating. Cells have membranes that allow solutions to move in or out and have specialized organelles, such as mitochondria, which provide the energy for all we do. The nucleus is where our DNA (what makes us us!) lives and cell division happens, without which we would literally be one … Continue reading