Introduction to Specialized Eukaryotic Cells and Tissues
While all cells share the same fundamental properties, cells in a multicellular animal become specialized to enable them to participate in different functions. Cells that find themselves in a human heart will have to be different structurally than cells found in the brain, due to the different functions these organs perform. Groups of similarly specialized cells working together towards a common function, along with any associated extracellular material, are called tissues. While experts can distinguish almost 200 types of human cells, these are usually grouped into four tissue types, each of which performs a basic function. These tissue types are epithelial, connective, muscle, and nervous.