How does your skin repair itself?
Your skin is your largest organ, with a surface area of about 20 square feet in adults. Your skin is made up of the epidermis (the outer protective layer of skin) and the dermis (the layer of skin below the epidermis that contains blood vessels and nerves). When your dermis is injured, your skin repairs itself by triggering a four-stage wound healing process that includes the production of collagen.
Here’s a breakdown:
- Homeostasis. Red blood cells form a blood clot that stops the bleeding and provides a temporary barrier to prevent the open wound from becoming infected.
- Inflammation. When dermal tissue is pierced, your immune system springs into action. Macrophages (white blood cells) disinfect the wound, remove debris and increase blood flow to the wound area. The swelling and skin redness you see after an injury are signs of inflammation.
- Proliferation. This is when the repair process begins. The wound is re-built with new granulation tissue—a combination of collagen and other extracellular matrix materials. Several important processes occur during proliferation:
- Granulation. Fibroblasts (cells that make up most of the dermis) move to the wound area. Fibroblasts produce collagen and elastin in the wound site, forming connective skin tissue to replace the damaged tissue. Healthy granulation tissue is uneven in texture. It does not bleed easily and is pink or red in color.
- Revascularization. A new network of blood vessels develops to deliver the oxygen and nutrients your fibroblasts need during the reconstruction process.
- Remodeling. During the final stage, newly formed collagen is rearranged and converted from type III to type I. This type of collagen adds strength to the wound, and the process causes the dermis to contract by 40 to 80 percent, pulling the wound edges together and closing the wound. This is like a shrink-wrap effect that tightens the skin.