In a similar way to an ant colony that works together, each individual playing a small part of a bigger machinery, the cells of humans and other multicellular organisms work together. Many cells of similar function and structure work together to form a higher unit. They use their extracellular matrices to link together and form a cohesive structure.

Early on in science, tissues were classed by the organ system they were found in, but there are many other ways to group these cooperative cell units. Embryologists often group tissues according to their embryonic origin, but they are most commonly grouped based on their function.

On the surface, tissues may just seem like any other part of a body, but when you really think about it, it’s amazing how these cells that billions of years ago lived independently for themselves have come together to form higher units. A tissue wouldn’t be a tissue unless every cell in it cooperated, and an organ wouldn’t be an organ… And a human is no more than a collection of nervous tissue communicating with the other tissues!