The lizard can regenerate not only its leg but can regenerate the lower jaw, tail, large parts of its brain, parts of the heart, and other internal organs such as the pancreas and the kidney. Regeneration is the best method of asexual reproduction in certain protozoans, sponges, coelenterates, and echinoderms. The organism develops from the lost worn-out parts. Members of the kingdom fungi and simple parts such as algae reproduced through unique reproductive structures.
Starfish can regenerate arms, and certain lizards can grow back severed tails. Some flatworms can recreate their entire body from a single adult cell. Also, human skin will grow back together after a paper cut on some level of little regeneration.
How do lizards regrow their tails?
Scientists have figured out how lizards regrow their tails, and that’s good news. By understanding the secret of how lizards regenerate their tails, researchers may be able to develop a way to stimulate the regeneration of limbs in humans. To regrow its tail lizard need to release its tail also. This is done by a process known as autotomy. Lizard’s tail contains three stages for regeneration of their tail.
- Wound healing.
Autotomy is also called self-amputation. In this process, some lizard detaches their tail from their body. It is a self-defense program done by lizards to protect their predators. When lizard uses their tail, they detach it from the vertebra present in the tail. The vertebra is the 13 individual interlocking bones from the spinal cord.
The tail lives from itself near the vertebra after the detachment. Animals such as womb salamander and spiders can also do autotomy. Spiders do autotomy when stung in a leg by a vest or bees. Then spider leaves their leg by splitting their venom on their leg to save their life.
To reduce the blood, lizards use a process known as wound healing. Wound healing means the replacement of dead or damaged tissues by new tissue. Every living organism does it. During wound healing in lizards, reticulocyte and epidermal epithelium cells around the worm site cover the wound. The epidermal cell closes to the world. In humans, four steps of wound healing take place.
- First, hemostasis is also known as blood clotting.
- Second inflammation, third low reformation, and fourth maturation.
Hemostasis is when the blood begins to stick to the injured to make it easier for wound healing. This blood also acts as a kind of glue. Then inflammation takes place. In this process, damaged and dead cells are cleared out with waste cells. Proliferation means new tissue made on the wound. When all this process is done, then final maturation takes place. After the wound healing process, the unnecessary cells of the body are deleted.
The wound epidermis activates a wave of chemical instructions to the cells below. The nerves in the stump begin to grow again. Mature muscle and tissue cells revert to their immature states before specialized cells. They then start streaming toward the wound, forming a mass called a blastema. These undifferentiated cells are like stem cells or embryonic cells during development before a gene is activated.
That tells them what they’re going to be like a liver or a heart or a skin cell. But these undifferentiated cells were mature. They have a terrific memory of what they used to be, like a muscle cell in a four-limb or a cartilage cell in a leg joint. This is how they take up their specific positions and form new muscle connective tissue cartilage and bone until the animal has a whole shiny new leg/tail.
Now the part is regeneration. After wound healing, a lot of fibroblasts are blastema. Blastema cell goes to make a new tail. What is a blastema cell? To know that, we need to understand stem cells. In the human body, there are organs like the heart and intestine. These intestines contain intestine cells, and these cells are constantly dying. So there are stem cells that become intestine cells. It happens in all bodies.
Stem cells contain such power that they can become any cell they want, like stem cells can become nerve cell muscle cells. These cells can become only intestine cells if they are present in the intestine. If the stem cell is in the liver, it cannot become bone or muscle cells. They have to become liver cells. Stem cells reproduce with mitosis. Mitosis is a process where a single cell divides into two identical daughters. But stem cells divide into two cells.
Number one cell is called a stem cell, and number two is the cell it wants to become like a blood cell or any other cell. Stem cells also help in many diseases like Alzheimer’s, heart diseases, stroke, burns, cancer, osteoarthritis, etc. After the bone healing process, these stem cells become muscle fibers. So on cells, skeletons make cartilage and bone.
During regeneration, stem cells become only the group of cells known as fibroblasts. Fibroblasts appear to play an essential role in bone healing. The group of fibroblasts now makes another cell known as blastema. This blastema now creates a new tail because blastema contains every cell needed to make a tail, and this is how a new tail forms.
- Stem cells make fibroblasts, fibroblasts make blastema, and blastema cells make a new tale.
Lizard’s tail experiment
Once a scientist named Emler Butler did a very remarkable experiment. Salamander can regrow its whole arm using the whole same process of regeneration. So the scientist has tried an exciting experiment in which he had cut the rest of the salamander and struck it back into the body.
Also, this made a connection of limb with the body. Then he cut the elbow, which means now it has two hands. And his two-hand will grow properly using bone healing and regeneration. It was a very remarkable experiment.
Researchers have recently pinpointed a cell that seems to be responsible for salamander’s remarkable regeneration capabilities. All animals have a kind of repair cell called macrophages. They rush into a wound site and eat up dead cells and pathogens while triggering the release of other immune cells.
Mammals also used them to repair muscle which got Dr. James Godwin of the Australian region of Medicine Institute. Godwin and his colleagues reduce the number of macrophages at a salamander wound site. They found that regeneration took much longer.
When they removed all the macrophages, the poor guys could no longer regrow limbs but instead ended up with a lot of scar tissue. So regeneration is possible because those macrophage cells release some vital chemical signal that might trigger the undifferentiated cells to come in and do their thing.
Frequently asked questions
Why can’t humans regrow a new limb?
In humans, regeneration takes a lot of energy. Our body doesn’t want to give a lot of energy. Instead of providing the energy, they make a habit of using one hand.
Why do lizards lose their tails?
Lizards lose their tail to defend themselves. When they feel attacked or fear, they remove their tail quickly. It makes a distraction to the predator and gives some time to escape.
Which animals regrow their body parts?
Many animals can regrow their body parts like Starfish, Deer, Axolotl, Spiders, Sea stars, Skinks, Worms, Conch, Crayfish, Zebrafish, etc.
Does it hurt when lizards lose their tails?
No, losing the tail does not feel hurt. It is a willingness and safety process. Also, it is like a game with a predator!
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Emberts, Z.; Escalante, I.; Bateman, P. W., “The ecology and evolution of autotomy.” Biological Reviews.
Congdon, J.D.; Vitt, L.J.; King, W.W., “Geckos: adaptive significance and energetics of tail autotomy.”