Connective tissues form the framework of the body, serving as binding and supporting elements.
Their morphology is variable, but the fundamental feature is that the cellular components are relatively inconspicuous, while the nonliving, intercellular material is abundant. The latter is composed of fibers suspended in a matrix or ground substance. Its main characteristic is the distribution of fibers among irregular spaces of varying size. The spaces, now empty, in life contained amorphous intercellular substances and tissue fluids. It is found here surrounding the cellular components of the kidney tubules.