סקירה כללית של חידוש ותיקון

Animal tissues frequently encounter damage due to accidental injuries and diseases, and also degenerate with aging.

Regeneration and repair are natural processes that help fix tissue damage and restore them to a certain extent.

Regeneration can physiologically restore damaged tissues and, in some animals, even complete organs, back to their fully-functional form.

For instance, some amphibians, such as salamanders, have extraordinary regeneration capabilities. They can fully regenerate their appendages, like limbs and tails; lower and upper jaws; and even the ocular tissues, including the retina and lens.

However, most animal tissues cannot regenerate fully. Instead, they heal through the repair mechanism, which can only reestablish the architecture of damaged tissue but not its complete function. Its main aim is to prevent blood loss and bacterial infection at the injury site.

For instance, injuries like burns and deep cuts in the skin are fixed by adding new connective tissues, mainly made up of cells and collagen, to the wound site; often, leaving behind a scar.