Our skin helps to keep countless bacteria, fungi and other foreign material from getting to our vital insides. So when we get wounded, it’s very important that our skin repairs itself. What happens when a wound heals?

Did You Know?
The skin is our largest organ. It serves as a waterproof coating, its sweat glands control our body temperature and it helps us perceive the sensation of touch.

Chances are, if you are cut, you’ll start bleeding because the vessels that supply the skin with blood has also been damaged. The first thing that happens is the injured vessel narrows to minimize the loss of blood. Next, cells that make up the blood vessels “call out” to tiny particles whizzing by in the circulatory system. These particles, known as platelets,will stop at the site of injury by clinging to the damaged vessel wall and triggering a complex clotting process known as the coagulation cascade. The result is the formation of a fibrin clot or “scab”, which stops the flow of blood.

Since the skin is cut, there is a chance it may get infected. Therefore, the immune system is called into action and white blood cells known as phagocytes, or “eating cells”, gobble up any intruders and digest them.

Did You Know?
When an infection is present you may see a white paste around the wound. This is an exudate (or pus) consisting of dead microbes and cell debris.

Underneath the protective scab, new blood vessels are created and the cells that form the epidermis and dermis layers of your skin multiply in numbers to form new sheets of skin. Fibroblasts are the cells that give the new skin its structure. These cells receive a signal to wake up out of their normally dormant state when their neighbours are wounded. They mainly produce proteins known as collagens to help close the wound.

When all of these processes are complete, the scab falls off to reveal the newly repaired skin.

When a cut or wound is really large or deep, scars can form. If this happens, it’s because the fibroblasts become overwhelmed by the large space they must help to seal. They will enter a state of “repair overdrive” to create extra amounts of collagen and other related sealants that form scars. Both surgical stitching and even skin grafting are commonplace to heal large wounds and prevent the majority of scarring.

Learn more!



Article first published March 2, 2011.

Photo credit:http://kerryosborne.oracle-guy.com/files/2009/06/band-aid-ko2.jpg

Kevin Donato

- Currently a Scientific Evaluator at the Marketed Pharmaceuticals and Medical Devices Bureau, Health Canada
  • Investigates suspected adverse reactions from medicines, and the ways to communicate and minimize the risk of these adverse events

- PhD, University of Toronto, Department of Laboratory Medicine and Pathobiology (2010)

  • research focused on studying the ways in which life-threatening bacteria and beneficial probiotics interact with our digestive tract 

- Has a passion for teaching science to diverse audiences, from kindergarteners to professionals, and has applied this interest during his
experiences as a science tutor and as a product development consultant

- Enjoys sailing, travelling, and culinary arts, when outside the office

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