GENERAL HISTOLOGY

Detailed explanation-1: -The fibroblast is one of the most abundant cell types present in the stroma. It has a variety of functions and composes the basic framework for tissues and organs. Under homeostasis, this cell is responsible for maintaining the extracellular matrix (ECM).

Detailed explanation-2: -Interleukin 4 (also known as “B cell stimulatory factor-1"), a cytokine product of T lymphocytes and mast cells, stimulates synthesis of the extracellular matrix proteins, types I and III collagen and fibronectin, by human dermal fibroblasts in vitro.

Detailed explanation-3: -ECM component proteins are secreted by a variety of cells surrounding muscle fibers, such as fibroblasts, endothelial cells, and skeletal muscle connective tissue cells [129, 130, 131].

Detailed explanation-4: -Fibroblasts are developmentally programmed to produce collagen matrix, which is the main structural component of connective tissue. Fibroblasts have cell surface receptors, called integrins, which specifically attach to proteins in the matrix including type I collagen.

Detailed explanation-5: -The ECM (extracellular matrix) is made up of glycoproteins such as collagen, proteoglycans, and fibronectin. It can regulate a cell’s behavior by communicating with a cell through integrins.