The main difference between repair and regeneration is that repair is the restoration of tissue architecture and function after an injury whereas regeneration is a type of healing in which new growth completely restores portions of damaged tissue to their normal state.
Repair and regeneration are two types of processes initiated after a tissue injury, reconstructing the damage. Repair takes place via two events: regeneration and replacement. Regeneration occurs through the proliferation of cells in the tissue while eplacement is a type of healing which occurs through scarring.
Key Areas Covered
1. What is Repair
– Definition, Process, Significance
2. What is Regeneration
– Definition, Process, Significance
3. What are the Similarities Between Repair and Regeneration
– Outline of Common Features
4. What is the Difference Between Repair and Regeneration
– Comparison of Key Differences
Key Terms
Cell Proliferation, Continuously-dividing Tissue, Permanent Tissue, Regeneration, Repair, Replacement, Scarring, Tissue Healing
What is Repair
Repair is one of the two tissue healing processes responsible for the healing major types of tissue injury. It restores both the structure and the function of the tissue after injury. In addition, the two processes involved in repair are regeneration and replacement. Regeneration causes the new growth of the tissue, occurring through the proliferation of the cells of the tissue. Moreover, it can restore minor types of tissue damages with no permanent damages remain. Therefore, regeneration alone can be considered as a process of tissue healing.
Figure 1: Tissue Repair
Furthermore, replacement is a unique process of tissue healing by repair. It only involves the repair of severely damaged tissues or damages with non-regenerable tissues. It is also responsible for the tissue repair by laying down of connective tissue. Therefore, this process is known as scarring. For example, a scar formed in the healing of myocardial infarction. However, this scar formation may result in structural abnormalities, which lead to the impairments of organ function. Nevertheless, a repair can restore some of the structures of the damaged tissue such as epithelial layers.
What is Regeneration
Regeneration is the second process responsible for tissue healing. It mainly involves restoring the main types of damages. Moreover, it is capable of completely restoring the portion of damaged tissue to the normal state. Generally, regeneration mainly occurs through the proliferation of cells of the damaged tissue. Here, the degree of regeneration depends on the type of tissue. Some tissues that are more capable of cellular proliferation are highly regenerable. And, this type of tissues is known as continuously-dividing tissues or liable tissues. Epithelia including skin, gastrointestinal epithelium, and salivary gland tissue and hematopoietic tissues are the examples of continuously-dividing tissues containing pools of stem cells that are self-renewable and proliferative.
Figure 2: Hematopoiesis
However, some tissues known as quiescent or stable tissues contain cells that normally exist in the non-dividing state. These cells can reenter a dividing phase upon a stimulus such as a cell injury. Parenchymal cells of the liver, kidney, and pancreas, mesenchymal cells including fibroblasts and smooth muscle cells, endothelial cells, and lymphocytes are examples of such cells. However, our body has permanent tissues that have left the cell cycle permanently. As an example, cardiac and skeletal muscles are unable to undergo regeneration upon an injury. Therefore, these tissues always leave permanent evidence of injury, such as a scar.
Similarities Between Repair and Regeneration
- Repair and regeneration are two types of processes initiated after tissue injury.
- They are the two components of the tissue healing process.
- Moreover, they are responsible for the reestablishment of the structure and the function of the injured tissue.
- Also, both processes are carried out by receptor-mediated signal transduction.
- Different types of growth factors mediate the signal transduction process.
Difference Between Repair and Regeneration
Definition
Repair refers to the restoration of tissue architecture and function after an injury while regeneration is a type of healing in which new growth completely restores portions of damaged tissue to their normal state. Thus, this is the main difference between repair and regeneration.
Significance
Moreover, repair takes place through two events – regeneration and replacement, while regeneration occurs through the proliferation of cells in the tissue.
Type of the Damage
Also, another difference between repair and regeneration is that repair heals major types of damages while regeneration heals minor types of damages.
Scarring
Scarring is also a difference between repair and regeneration. Repair involves the formation of scar tissues while regeneration does not involve the formation of scar tissues.
Result in
Although repair may restore some of the original structures of the damaged tissue, it may also result in structural abnormalities that impair organ function. However, regeneration is capable of healing the damage with no permanent impairment.
Conclusion
Repair is a type of tissue healing involved in healing major damages. It occurs through two processes: regeneration and replacement. In regeneration, stem cells or specialized cells in a tissue undergo proliferation to restore dead or damaged cells. It can heal minor tissue damages. In replacement, the non-regenerable tissues are repaired by laying a connective tissue layer. Although repair may remain some structural abnormalities, regeneration restores the original tissue. Thus, the main difference between repair and regeneration is the process and result.
References:
1. Krafts, Kristine P. “Tissue repair: The hidden drama.” Organogenesis vol. 6,4 (2010): 225-33. doi:10.4161/org.6.4.12555.
Image Courtesy:
1. “417 Tissue Repair” By OpenStax College – Anatomy & Physiology, Connexions Web site. Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia
2. “Hematopoiesis simple” By Mikael Häggström and A. Rad – Image:Hematopoiesis (human) diagram.png by A. Rad (CC BY-SA 3.0) via Commons Wikimedia
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