Definition of Fibroblasts

Learning Objective:

Upon completion of this module, students should be able to:

1. Define and describe the anatomical characteristics and cellular structure of fibroblasts, with a focus on their spindle-shaped structure and rough endoplasmic reticulum.
2. Understand and explain the physiological roles of fibroblasts, particularly their role in the synthesis of the extracellular matrix and their function in maintaining tissue structural integrity.
3. Describe the process of wound healing and the transformation of fibroblasts into myofibroblasts, demonstrating an understanding of the importance of fibroblasts in tissue repair and regeneration.
4. Discuss the relevance of fibroblasts in the field of kinesiology, including their influence on the function of muscles, tendons, and ligaments.
5. Appraise the potential pathological roles of fibroblasts and evaluate the need for further research into fibroblast biology and their roles in various diseases.

By achieving these objectives, students will gain a comprehensive understanding of the multifaceted role of fibroblasts in human anatomy and physiology, and their significance in medical and health-related research.

Fibroblasts are the most common type of cells found in connective tissue in animals (Alberts et al., 2002). They play a pivotal role in the production of the extracellular matrix, contributing to the structural integrity of most tissues and playing a key role in wound healing (Sorrell & Caplan, 2009).

Anatomically, fibroblasts have a unique structure that makes them well suited for their role in the body. They are typically spindle-shaped, with a nucleus rich in DNA at the center of the cell (Alberts et al., 2002). This shape and internal structure allow fibroblasts to stretch and change shape, which is important for their role in the movement and resilience of connective tissues.

The cytoplasm of fibroblasts is rich in rough endoplasmic reticulum (rER), a network of membranes involved in protein and lipid synthesis (Alberts et al., 2002). The rER appears "rough" because it is studded with ribosomes, the molecular machines that synthesize proteins. The high quantity of rER in fibroblasts is indicative of their high rate of protein synthesis, particularly of collagen, a major component of the extracellular matrix (Shoulders & Raines, 2009).

Physiologically, fibroblasts are central to the maintenance and repair of bodily tissues. As key producers of the extracellular matrix, fibroblasts help to provide a supportive framework for other cells and tissues, maintaining their shape and strength (Kadler et al., 2007). When tissue damage occurs, fibroblasts are able to proliferate rapidly, migrate into the wound area, and begin producing the proteins necessary to repair the damage. During this process, they can differentiate into myofibroblasts, specialized cells that contribute to the contraction of wound edges, promoting healing and reducing scar size (Darby et al., 2014).

Understanding the anatomy and physiology of fibroblasts provides crucial insights into their role in kinesiology. As key contributors to the structure and resilience of connective tissues, fibroblasts play a critical role in the function of muscles, tendons, and ligaments. Further research into the functions and pathological roles of fibroblasts is needed to fully understand their potential as therapeutic targets in a range of diseases, including fibrosis and cancer.

References:

• Alberts, B., Johnson, A., Lewis, J., et al. (2002). Molecular Biology of the Cell. Garland Science.
• Sorrell, J. M., & Caplan, A. I. (2009). Fibroblasts-a diverse population at the center of it all. International Review of Cell and Molecular Biology, 276, 161–214.
• Shoulders, M. D., & Raines, R. T. (2009). Collagen Structure and Stability. Annual Review of Biochemistry, 78, 929–958.
• Kadler, K. E., Baldock, C., Bella, J., & Boot-Handford, R. P. (2007). Collagens at a glance. Journal of Cell Science, 120(12), 1955–1958.
• Darby, I., Skalli, O., & Gabbiani, G. (1990). Alpha-smooth muscle actin is transiently expressed by myofibroblasts during experimental wound healing. Laboratory investigation, 63(1), 21–29.