Chapter 5 What cells can do
In animals and plants, cells are grouped together in tissues and organs. Each organ is formed of a mixture of tissues which themselves contain several different cell types that work together to perform the tasks needed for the survival and reproduction of the organism. Connective tissue is characterized by large amounts of extracellular matrix secreted by well-separated cells, providing skeletal tissues such as bone, cartilage, tendons, and ligaments that make up the structural framework of the body. The more sophisticated the organism, the more complex and numerous are its cell types. In evolutionary terms, this allows for the creation of specialist cells that can respond to and survive a wide range of challenges. In this chapter we examine varied examples of cell specialisms that allow an organism to protect itself and respond to its environment.