‘Goodness!’ cried Marie, clapping her hands together, ‘What has Godfather Drosselmayer brought us?’ “
The Nutracker, Alexandre Dumas
It’s kind of weird, when you think about it, how much time we spent in the last chapter talking about cells. After all, we are not cells. Sure we’re made of cells, but that doesn’t make us cells any more than my dog is fur because she has a lot of it and spreads it all. over. the house. How is it that we get from a nerve cell to…us? What would we have to do to go from a skin cell to a skink? (You add a “k,” of course)
In creatures made of more than one cell (multicellular creatures, such as fungi, plants, animals, and some protists), individual cells work together to form tissues – thin pieces of cells that are of the same type that work together. For example, a single muscle cell might form together with other muscle cells to make muscle tissue. Think of it like a single red thread that is woven together with other red threads to make fabric. Each individual thread is still there but it has now become something different: fabric. Tissues include the towering brown algae and some types of moss, all well as those found in other plants and fungi. In animals, we have tissues that are hard to make things like bones, soft like fat, or even liquid for blood (yes, blood is a kind of tissue).
Of course, we aren’t tissues either. (Could you imagine being a wispy piece of tissue, billowing around in the ocean like kelp?) In animals and most plants (but not fungi or protists), tissues team up with other tissues with a similar function (job) in order to make an organ. We could take that muscle tissue from earlier and put it together with some cartilage (a kind of connective tissue) and some skin tissue and make lungs. Similarly, we could take that red fabric and put it together with some white fabric and gold buttons and make a fetching soldier’s jacket. Your organs range from the tiny pineal [pin-ee-ul] gland (a part of your brain about as big as three grains of rice that helps you sleep) all the way up to your skin (which is one giant organ).
Even though organs are super important, that is not all the order that you have in your body. Organs work together with other organs to make organ systems, such as the nervous system (which includes your brain and controls your body), the digestive system (which breaks down the food you eat), and the respiratory system (of which your lungs are the star). You can think of it as taking that red soldier jacket and putting it with ballet slippers and a giant mask with a tall red hat to make a costume for the Nutcracker ballet. Each piece of the outfit is separate, but, when you put it together, it makes something more. All of your body’s organ systems work together to make you. In complex creatures, we always see the same pattern: cells make tissues, which make organs, which make organ systems, which make the body.