The human body is made up of many different types of tissues.
Tissues are collections of the same type of cell. For instance, neural tissue could be made up of neurons, and muscle tissue made up of muscle fibres.
In any multicellular organism, cellular organisation into tissues is important for the cooperative function of similar cells to perform a particular function. Without cellular organisation into tissues, whole organs – which can be made up of several tissues – would not be able to function.