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.
1 The third number is the wheel size: 16 indicates the wheel diameter in inches the tire is designed to fit. In this case a 16-inch wheel.  The last number refers to the load index: In this case, 67 is the load index designation. In this example 67 informs the consumer that the tireâs maximum load capacity is 661 lbs.