Histology and the Extracellular Matrix

A set of vocabulary flashcards covering the basic concepts of histology, four tissue types, and extracellular matrix components.

Histology

The study of the normal structure of tissues.

Tissue

A discrete population of cells related in structure and function, surrounded by extracellular matrix (ECM).

Epithelial tissues

Tissues consisting of tightly packed sheets of cells with no visible ECM that cover and line all body surfaces and cavities, and form glands that manufacture secretions or chemical messengers.

Connective tissues

Tissues that connect tissues to one another, where ECM is a prominent feature with cells scattered throughout to bind, support, protect, and transport substances.

Muscle tissues

Tissues capable of contraction.

Nervous tissues

Tissues consisting of cells capable of sending and receiving messages (neurons) and cells that support this activity (neuroglia).

Neurons

Cells in nervous tissue capable of generating, sending, and receiving messages.

Neuroglia

Cells in nervous tissue that support the activity of neurons.

Extracellular Matrix (ECM)

Substances in a liquid, gel, or solid state surrounding cells that provide tissue strength to resist tensile and compressive forces, direct cells to proper positions, and regulate cell development, mitotic activity, and survival.

Ground substances

The component making up most of the ECM, consisting of water, nutrients, ions, and macromolecules.

Glycosaminoglycans (GAGs)

Macromolecules in the ground substance such as chondroitin sulfate (found in cartilage) and hyaluronic acid.

Proteoglycans

Macromolecules composed of GAGs bound to a protein core.

Cell-adhesion molecules (CAMs)

Macromolecules made up of different types of glycoproteins that bind surface proteins and maintain the architecture of the tissue.

Collagen fibers

White, fibrous protein fibers making up 20\text{-}25\text{\null}\% of all proteins in the body that are resistant to tension and pressure.

Elastic fibers

Yellow protein fibers composed of the protein elastin surrounded by glycoproteins that exhibit elasticity.

Reticular fibers

Weblike protein fibers forming a meshwork or scaffold that support cells and ground tissue of many tissues.