Fibroblasts: Definition

Fibroblasts are a type of cell normally found in connective tissue. They play an important role in maintaining the structural framework of tissues and organs in the body. They are one the most common types of cells found in connective tissue and are primarily involved in producing and secreting the extracellular matrix, which provides structural support and a framework for various tissues.

What is the function of fibroblasts?

Functions of fibroblasts include:

• Extracellular matrix production: Fibroblasts are responsible for producing and secreting proteins such as collagen, elastin, and glycoproteins, which form the extracellular matrix. This matrix contributes to the strength, elasticity, and structure of tissues.
• Wound healing: These cells are vital in the process of wound healing and tissue repair. After an injury, they travel to the site of damage, proliferate (by undergoing a process called mitosis), and produce extracellular matrix components to aid in the formation of scar tissue.
• Tissue maintenance: Fibroblasts contribute to the ongoing maintenance and remodeling of tissues. They continuously produce and modify the extracellular matrix to ensure the integrity and functionality of tissues.
• Regulation of inflammation: These cells play a role in regulating immune responses and inflammation by producing and secreting chemicals that signal immune cells about changes within tissues.

Where are fibroblasts normally found?

Fibroblasts are found throughout the body in various connective tissues, including:

• Dermis of the skin: Fibroblasts are abundant in the dermal layer of the skin, where they contribute to the strength and elasticity of the skin.
• Tendons and ligaments: These cells are present in tendons and ligaments, where they help maintain the structural integrity of these tissues.
• Bone marrow: In the bone marrow these cells are involved in the production of the stromal framework that supports blood cell formation.
• Organs: Fibroblasts are found in the stroma of various organs, providing structural support and contributing to the overall architecture of tissues.
• Connective tissue throughout the body: Fibroblasts are dispersed in connective tissues surrounding blood vessels, nerves, and other organs, ensuring their structural integrity.

What do these cells look like under the microscope?

Fibroblasts, when examined under the microscope, appear as elongated, spindle-shaped cells with a fusiform or stellate morphology, often featuring tapered or branched ends. Their relatively large, oval, or cigar-shaped nuclei contain prominent nucleoli, while a moderate amount of pale cytoplasm surrounds the nucleus. Fibroblasts commonly exhibit cellular extensions or processes that contribute to their distinctive spindle or stellate appearance.

Are fibroblasts found in tumours?

Cells that resemble fibroblasts are found in many different types of tumours, both benign (noncancerous) and malignant (cancerous). Pathologists often refer to these cells as fibroblastic or showing fibroblastic differentiation. Fibrosarcoma is a type of cancer made up entirely of fibroblastic cells.