How the cells are regenerated in the body
As part of the natural process of maintaining tissues and organs, all living things have the ability to regenerate. Some animals have extensive regenerative capabilities. For example, a small freshwater animal called Hydra can form two wholes after being cut in half. Absolutl or Mexican salamander is an animal with a spine that can regenerate the shape and function of almost any limb, organ, or other part of the body.
More complex animals, such as mammals, have limited regenerative capacity. These include:
Thick tissue and skin damage to promote healing of injured or amputation body parts.
Hair and skin are aging.
Heal fractures by using new tissue to hold bone fragments together.
Living things regenerate in different ways. Plants and some marine organisms, such as jellyfish, can replace the lost parts, extensively conditioning the remaining tissues. Some animals, such as crayfish, catfish and lizards, replace the missing parts by implanting the spores first. Germ cells divide rapidly to form skin, scales, muscle, bone, or cartilage, all needed to create missing limbs, fins, or tails. In some animals, which includes humans, organs such as the liver undergo what is known as compensatory hypertrophy. When part of the liver is removed or destroyed, the remaining part will grow to its original size and allow the liver to function as before. Some organs such as kidneys, pancreas, thyroid, adrenal glands, and lungs compensate for organ loss in a similar but limited way. Research organisms particularly useful for studying regeneration include blue-and-white striped zebrafish and plantar worms, a type of flatworm. Zebrafish can replace damaged or lost fins; They can also repair serious damage to the heart, pancreas, retina, brain and even the spinal cord.
Stem cells play an important role in regeneration because they can grow into many different types of cells in the body and renew themselves millions of times. This is something special cells such as neurons cannot do. The main function of stem cells is to maintain and repair the tissues they are in. Scientists are studying whether a person's stem cells can "grow" into replacement tissues that are not rejected by the body's immune system.
During an organism's life cycle, its cells regenerate. But as part of the process, this ability gradually diminishes. To better understand the changes that have taken place, scientists study animals that show few signs of aging during their life cycle. Sea urchins, for example, can reproduce and regenerate damaged parts during their lifetime.