Veterinary Histology and Embryology

REPAIR AND REGENERATION OF ADULT TISSUES

• Epithelium: In contrast to the more highly differentiated tissues like the nerve cells and skeletal muscle fibres epithelium has a capacity for cell division and repair if the injury is not very extensive.
• Connective tissue proper has the greatest powers for regenerations and repair and is the tissue involved in the healing process of wounds and the regenerating tissue is known as granulation tissue is known as granulation tissue. Regeneration of cartilage is a slow process and possibly does not occur at all in many instances. Osseous tissue has powers of regeneration and repair.
• Smooth muscle has limited powers of regeneration that of skeletal muscle is restricted, while the regenerative capacity of adult heart muscle is very slight.
• In nervous tissue in the adult, when nerve cell body dies, there will be no regeneration or replacement by mitotic division of existing cells. But when the cell body is intact the nerve fibre or axon alone is injured distal to the injury there is degeneration leading to complete break down and disappearance of the portion of the nerve fibre including its terminal arborization (Wallerian or secondary degeneration). But proximal to the injury, after certain initial degenerative processes, regeneration occurs leading to a new growth from the injured end. Changes in the nerve cell body (e.g) Chromatolysis also occur and fibre regeneration occurs only if the cell body survives, it depends also on the type of neuron, nature and location of the site of injury etc.