Odds are that you’ve gotten hurt at some point. Cuts, scrapes, burns, and the occasional broken bone – these are all a normal part of life, and for the most part, they heal up pretty nicely with a little TLC.
But… how exactly does it happen? What’s going on under your band-aid to help your skin knit itself back together? Well, as a certified comic book expert and a nerd-king of pop culture mountain, I’d like to present Exhibit A.
Yes, the world’s first and greatest Canadian Super Hero: Wolverine. Ol’ Logan has been put through the wringer time and time again, and manages to come out unscathed every time (except for when he gets cut by evil magical katanas, or when a sentient virus from the multiverse shuts down his healing factor, but those are edge cases.) For Wolverine, getting a leg cut off is a minor inconvenience – he can take an aspirin, sit down for a day, and be back to sprinting tomorrow.
However, we non-mutants don’t have it quite as easy. It takes a lot of time and energy for a body to put itself back together, even after relatively minor injuries. Despite the speed at which it takes place, the process behind the healing of wounds is really something spectacular all on its own.
Step One: Clotting
The first job your body has when reacting to an injury is stopping you from bleeding out, so closing the wound takes priority. First, your blood reacts to the disruption. Tiny, specialized blood cells called Platelets react to the wound and “activate,” making them seek out and latch onto other platelets and proteins in your blood to form a blood clot.
The activated platelets continue grabbing onto each other to form a protective shield around the injury, which has the double bonus of keeping your blood from leaving your body, and keeping bacteria and viruses from getting in.
When blood fails to clot properly, the healing process can’t begin in earnest, which is why Hemophilia, a group of genetic conditions that affect the ability of specific proteins in the blood to form clots, is such a dangerous condition. A hemophiliac’s wounds are slower to heal, which leaves them much more susceptible to disease and blood loss.
The two most common types of diseases that affect clotting are Type A Hemophilia and a similar illness called Von Willebrand’s disease (or Pseudohemophilia). Type A Hemophilia occurs in around 1 in 5,000 males, and Von Willebrand’s Disease occurs in about 1% of the population. Other types of Hemophilia that affect different clotting proteins are far less common, but can still lead to similar problems of varying degrees of severity.
Depending on the percentage of clotting proteins affected by a person’s inherited genes, Hemophilia can be classified as mild, moderate or severe. Typically, a person will only notice a real difference in amount of bleeding if their clotting proteins operate below 50% efficiency. Between 40% and 6% clotting factor efficiency is a “Mild” case of Hemophilia, which is typically only a problem with serious injuries or after surgery. Between 5% and 1% clotting factor is considered “Moderate,” and less than 1% is “Severe.”
Because Hemophilia hampers the body’s natural ability to heal, it often increases the mortality rate associated with lots of other conditions in the body. For example, even minor surgeries that need to be completed in the future have a higher risk of complication due to the increased blood loss suffered by hemophiliacs.
Because of the increased risk of death that comes with any level of Hempohilia, health-dependent businesses and services like life insurance carriers tend to be very stringent towards Hemophilia sufferers. Even mild Type A Hemophilia will result in an automatic downgrade to standard life insurance rates in most cases, with increases in severity and the presence of complicating factors pushing you well into table rating territory.
Hemophilia doesn’t mean that your blood can’t form protective clots, it just means that your body is slower at forming those protective barriers, which can increase the length of time it takes for wounds to heal.
Cuts and Scrapes
For surface wounds, the protective blood clot takes the form of a scab, which seals up the injury and allows the reconstruction process to begin in earnest. After you stop bleeding, your body releases antibodies and white blood cells to the area of the cut to mop up any bacteria or viruses that have made their way into your system while the wound was open to the world.
As your natural defenses fight off infection, your body increases blood flow to the wound and increase the amount of raw materials it needs in order to repair the damage. This increase in traffic is why wounds heat up and become inflamed during the healing process.
At the same time, Macrophages, the body’s cleanup crew, enter the wound site and get rid of any debris like dirt and dust, broken skin and muscle particles that entered the body, and even bone fragments, if the wound is deep enough. Think of them as microscopic Matter Eater Lads patrolling your body and eating anything that isn’t supposed to be there.
After everything’s cleaned up, red blood cells kick into high gear and create a fibrous layer of collagen beneath the wound, which acts like a foundation that the new flesh and skin can be built upon.
Up at the surface of the injury, cells called Miyofibroblasts work at a cellular level to help pull the existing skin back towards its natural resting point by pulling the edges of a wound together. When the existing skin is pulled as tightly as possible, any remaining space is taken up by granulation tissue – the bumpy, pinkish skin that covers the majority of the healing wound.
This temporary skin is full of microscopic blood vessels that help ferry Macrophages around to clean up the unnecessary scaffolding and tools the body uses in order to heal completely. After the cleanup is complete, the rest of the unnecessary cells undergo a process called apoptosis, which is a pre-programmed disintegration of unnecessary cells. The destroyed cells are then absorbed back into the body.
Depending on the size of the wound, the bumpy granulation tissue might need to be larger and sturdier in order to allow for healing to take place, which is why big wounds leave scars – the stronger, more tightly packed portion of skin is just built on the infrastructure that was left behind during the healing process.
With a skeleton covered in adamantium, Wolverine hasn’t had to deal with broken bones too much over the course of his career. Before the Weapon X program got ahold of him, however, he broke his bones just as easily as the rest of us. Thankfully, his healing factor also helped him dodge the weeks-long healing process.
The first steps in the healing of a bone are actually pretty similar to the process for flesh wounds. As soon as a bone breaks, blood rushes into the area and forms a protective clot before carrying phagocytes into the area to clean up any loose bone fragments that would get in the way of the bone healing properly.
Next, a group of cells called Chondroblasts creates a “Callus” around the break made of soft collagen. The collagen matrix is only a little bit denser than the cartilage that forms the bridge of your nose, so the limb still isn’t sturdy enough to bear weight. However, it does allow the longest portion of the healing process to begin in earnest.
Once everything is wrapped up tight by the collagen callus, new bone begins to form. Starting from the broken edges of the existing bone, cells called osteoblasts are released into the callus to spin a web of osteoid, a sponge-like type of bone that serves as a foundation. Then, your body ferries minerals like calcium to the wounded area and deposits them into the holes in the osteoid, which forms solid bone.
That process involves slow, steady growth from your bone’s “Ossificaton Centers,” which are centrally located points in your bones that serve as starting points for bone repair. Small bones, like the ones in your hands, normally have ossification centers located in the dead center of the bone, while longer bones have evenly-spaced ossification centers throughout – for arm and leg bones, one is located on each end, with a third in the center.
From top to bottom, the process of healing a broken bone takes around 6 to 12 weeks to reach a solid level of stability, leaving a dense “knot” of new bone in the place where the callus was located. Over the next 3 to 9 years, your bone will be “remodeled,” as cells called Osteoclasts (not to be confused with Osteoblasts) break down the extra bone and fill in any gaps. After that process is complete, your bone will be as good as new!
While we can’t heal quite as fast as a comic book hero, there’s nothing boring about the way our bodies work. In all honesty, Wolverine’s healing ability actually does mirror some of the basic concepts of biology, and might be one of the most believable powers in comics. Well, aside from Clock King’s time-telling abilities, that is.
Header Photo Credit to Daniel Lobo
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