A fibroblast is a type of cell that synthesizes the extracellular matrix and collagen,[1] the structural framework (stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells of connective tissue in animals.
For example, a 700 x 20 C road tire would be a 20-622; a 700 x 38 hybrid tire would be a 38-622. The width difference between these sizes would make them less-than ideal replacements for one another, but any rim that could fit one of them would work after a fashion with the other.
The dimensions of the tires are usually 28 x 12 x 15, being the diameter, width, and wheel rim diameter. In standard tire description, this corresponds to 300/54 R15, which is an ultra-low profile: height/width = 54%.