Name: 【TED-Ed】How do scars form? - Sarthak Sinha
Uploaded: 2014-11-30T12:52:36.000Z
Duration: 3 min 42 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Remember the time you fell off your bike or bumped your head on a sharp corner?

Childhood injuries are things we'd often like to forget,

but our bodies often carry the memories in the form of scars.

So what are these unwanted souvenirs  and why do we keep them for so long

after that unintended vacation to the emergency room?

The most common place we see scars are on our skin,

a patch that looks slightly different from the normal skin around it.

Often, this is considered an unfortunate disfigurement,

while other times, deliberate  scarification has been used

in both traditional and modern cultures to mark a right of passage

When we look at healthy skin tissue under a microscope,

we see the cells that perform various functions

connected by an extra cellular matrix, or ECM.

This is composed of structural proteins, like collagen,

secreted by specialized fibroblast cells.

Well-arranged ECM allows for transportation of nutrients,

cell to cell communication, and cell adhesion.

But when a deep wound occurs, this arrangement is disrupted.

During the process of wound healing, collagen is redeposited at the wound site,

but instead of the basket-weave formation found in healthy tissue,

the new ECM is aligned  in a single direction,

impeding inter-cell processes, and reducing durability and elasticity.

To make matters worse,  the healed tissue contains

a higher proportion of ECM than before, reducing its overall function.

In the skin, the overabundance of collagen interferes with its original functions,

like producing sweat, controlling body temperature and even growing hair.

The scar tissue is fragile, sensitive to changes in temperature and sensation,

and should be kept in moist environments to maximize healing.

This presence of excessive fibrous connective tissue in an organ

is known as fibrosis, and if that term sounds familiar,

it's because our skin is not the only organ vulnerable to scarring.

Cystic fibrosis is a genetic disorder that causes scarring of the pancreas,

while pulmonary fibrosis is a scarring of the lungs,

Scarring of the heart and the buildup of ECM following a heart attack

can inhibit its beating, leading to further heart problems.

is that although it retains some of the original functions,

the scar tissue formed after a wound is inferior to the native tissue it replaces.

Medical researchers are now studying what causes fibroblast cells

and how we can recruit  the body's other cells

in regenerating and repopulating the damaged tissue.

By learning how to better control wound healing and the formation of scar tissue,

we can utilize the multi-billion dollar budgets currently used to address

the aftermath of wounding in a much more efficient manner,

and help millions of people live better and healthier lives.

But until then, at least some of our scars

can help us remember to avoid the sorts of things that cause them.