In connective tissue, the extracellular matrix consists of:

In connective tissue, the extracellular matrix consists of:

A) ground substance only.

B) ground substance and intracellular fluid.

C) cells and protein fibers.

D) protein fibers and ground substance.

E) cells and ground substance.

Answer: D) protein fibers and ground substance.

Connective tissue has an exclusive structural network known as the extracellular matrix (ECM) that is composed of protein fibres and ground substances. It gives shape and architecture, as well as chemical support to the other cells adjacent to it. The ground substance, a semi-fluid gel containing water and glycoproteins, holds collagen, elastin, and reticular fibres that are responsible for strength, elasticity and cell support system respectively. While collagen contributes to tensile strength, elastin enables the tissue to regain its shape, and reticular fibres form a supporting network. The ground substance is a viscous medium containing proteoglycan, glycosaminoglycans, and glycoproteins. It occupies the interstitial space among fibres and cells, offers a water supply, assists in moving nutrients and wastes, and defines the tissue properties. Thus, the balance of both protein fibres and ground substance helps the connective tissues serve several functions such as support and protection of other tissues and organs as well as joining of tissues of different types. Thus, the particular constituents of the ECM tend to be diverse across distinct forms of connective tissues since they perform different functions in an organism.