In connective tissue, ground substance is the non-cellular components of extracellular matrix which contain the fibers.
It is usually not visible on slides, because it is removed during the preparation process.
Cells are surrounded by extracellular matrix in tissues, which acts as a support for the cells. Ground substance traditionally does not include collagen but does include all the other proteinaceous components, including proteoglycans, matrix proteins and, most prevalent, water. The non-collagenous components of extracellular matrix will vary depending on the tissue in which it is found.
Ground substance is amorphous, gel-like, and is primarily composed of glycosaminoglycans (most notably hyaluronan), proteoglycans, and glycoproteins.
The meaning of the term has evolved over time.
Famous quotes containing the words ground and/or substance:
“On every tree a bucket with a lid,
And on black ground a bear-skin rug of snow.
The sparks made no attempt to be the moon.
They were content to figure in the trees
As Leo, Orion, and the Pleiades.
And that was what the boughs were full of soon.”
—Robert Frost (1874–1963)
“What makes literature interesting is that it does not survive its translation. The characters in a novel are made out of the sentences. That’s what their substance is.”
—Jonathan Miller (b. 1936)