In this lesson, you’re going to learn the fundamental facts about the three phases of wound healing.
These phases include inflammation, proliferation, and maturation. When you are through, take the quiz to see what you have learned.
What Is a Wound?
Whether it’s due to sports, or a medical problem, or maybe an accident like a fall down some steps, you might get a nasty wound. A wound is just an injury to an organ or tissue of the body that results in a disruption of the normal continuity of that organ or tissue. That’s a mouthful, but I know you can relate to this because you’ve certainly had a wound on your skin before. The skin is an organ of your body. The wound, let’s just say it was a cut, disrupted the normal cohesion or unity of the skin.
The skin was broken, and that’s what I mean by a disruption of normal continuity.That wasn’t hard to understand, was it? Probably not. In that case, let’s move on to the three phases of wound healing. I promise I’ll make it easy on you.
First Phase of Wound Healing
The first phase of wound healing is the coagulation/inflammatory phase. Sometimes, this phase is actually split into two separate phases.
However, it’s easier to combine it into one because both of the aspects of this phase start to occur at pretty much the same time.Coagulation is another word for clotting, and inflammation is a local protective response to an injury that helps to dilute, destroy, or wall off the injured tissue or the agent responsible for the injury.Important signs of inflammation include:
- In some instances, a loss of function of the area in question
What happens in this phase is as follows. After you cut your skin, the broken blood vessels of the skin begin to gush out blood. Not good. The body does not want to lose blood. That’s why platelets(cells that plug up holes in blood vessels) stick to the damaged blood vessels and initiate a cascade of steps that results in the clotting of blood.
The clotting of blood plugs up the holes in the broken blood vessels and the bleeding stops. Yay!The platelets, as well as other cells, also release chemicals that help attract inflammatory cells called white blood cells into the area. These guys are here to ensure that whatever agent, be it chemical or biological, which has caused the injury or entered into the body as a result of the injury is destroyed or walled off behind a jail-like compound. The white blood cells also release inflammatory compounds that cause you to experience the signs of inflammation I just went over.
Second Phase of Wound Healing
As the inflammation eventually subsides, the second phase of wound healing, the proliferative phase, begins.
The inflammatory cells that I mentioned before release compounds called growth factors. These growth factors are ultimately responsible for the formation of granulation tissue. This is a fancy term for tissue formed to repair soft tissue wounds. You can think of it as a natural patch or Band-Aid your body tries to create to protect and repair the wound.
Something else happens during this phase. Remember how I said the first phase can be split into two phases because of overlapping events? Well, pretty much all of these phases of wound healing overlap in some way or another. It’s one continuous and overlapping process.One key example of this is that of angiogenesis, the creation of new blood vessels, which begins in phase one but doesn’t really take off until phase two. That’s why I stuck it in this section.
Angiogenesis is super important. If a bunch of underwater pipes that water the grass on top of them burst, the grass will die without new pipes being installed, right? Well, the injury that took place burst and incapacitated a bunch of your body’s internal pipes (the blood vessels). If the injured area is to avoid dying off like the grass, the body grows new pipes (new blood vessels) to support wound healing. Why are these blood vessels important? It’s because they provide nutrients for cells to grow and repair the wound.
Third Phase Of Wound Healing
Once a normal blood supply has been re-established, the third phase of wound healing, the maturation (remodeling) phase can begin. Here, the wound is constantly altered in how it looks, the cells that make it up, and even its strength.This is the part of wound healing where you see scars appear. What’s important to remember about this phase is that remodeling proceeds slowly. This means that the strength of the newly deposited tissue increases slowly over a pretty long period of time – months to a couple of years.
In most cases, the wound does not recover the full strength of the original tissue after the remodeling phase is complete. Most wounds are about 20% weaker than the original tissue. However, some tissues like bones or the bladder may regain 100% of their original strength.
Let’s wind this wound lesson up. A wound is just an injury to an organ or tissue of the body that results in a disruption of the normal continuity of that organ or tissue.
Once you’ve been wounded, the first phase of wound healing, the coagulation/inflammatory phase, can begin. Coagulation is another word for clotting, and inflammation is a local protective response to an injury that helps to dilute, destroy, or wall off the injured tissue or the agent responsible for the injury. In this phase, bleeding stops and inflammation kills or tries to kill any harmful agent that may have entered your body.The second phase of wound healing, the proliferative phase, begins thereafter with the formation of granulation tissue, protective tissue that helps repair and protect the wound. This phase is also the one where angiogenesis, the creation of new blood vessels, is super important to support the granulation tissue.Finally, the third phase of wound healing, the maturation (remodeling) phase, occurs thereafter, as the wound changes slowly over time, and scar tissue may develop.