How a wound heals itself - Sarthak Sinha

Kako se leče rane - Sartak Sinha (Sarthak Sinha)

Prevodilac: Mile Živković Lektor: Anja Saric

The largest organ in your body isn't your liver or your brain.

Najveći organ u vašem telu nije jetra ili mozak.

It's your skin, with a surface area of about 20 square feet in adults.

To je vaša koža, sa površinom od skoro 2 kvardatna metra kod odraslih.

Though different areas of the skin have different characteristics,

Iako različiti delovi kože imaju različite karakteristike,

much of this surface performs similar functions,

većina ove površine vrši slične funkcije,

such as sweating, feeling heat and cold, and growing hair.

poput znojenja, osećaja toplote i hladnoće, kao i rasta dlaka.

But after a deep cut or wound,

Ali nakon duboke posekotine ili rane,

the newly healed skin will look different from the surrounding area,

sveže zalečena koža će izgledati drugačije od okoline

and may not fully regain all its abilities for a while, or at all.

i možda neće neko vreme, ili uopšte, povratiti sve svoje sposobnosti.

To understand why this happens, we need to look at the structure of the human skin.

Kako bismo razumeli zašto se ovo dešava, moramo pogledati strukturu ljudske kože.

The top layer, called the epidermis,

Gornji sloj, epidermis,

consists mostly of hardened cells, called keratinocytes,

sastoji se većinom od stvrdnutih ćelija, keratinocita,

and provides protection.

i pruža zaštitu.

Since its outer layer is constantly being shed and renewed,

S obzirom da se njegov spoljašnji deo stalno guli i obnavlja,

it's pretty easy to repair.

prilično se lako oporavlja.

But sometimes a wound penetrates into the dermis,

Ali ponekad rana probije u dermis,

which contains blood vessels and the various glands and nerve endings

koji sadrži krvne sudove i razne žlezde i nervne završetke

that enable the skin's many functions.

koji omogućavaju mnoge od funkcija kože.

And when that happens, it triggers the four overlapping stages

Kada se to desi, pokreću se četiri faze

of the regenerative process.

regenerativnog procesa, koje se preklapaju.

The first stage, hemostasis, is the skin's response to two immediate threats:

Prva faza, hemostaza, je odgovor kože na dve neposredne pretnje -

that you're now losing blood

to što gubite krv

and that the physical barrier of the epidermis has been compromised.

i to što je fizička prepreka u vidu epidermisa sada ugrožena.

As the blood vessels tighten to minimize the bleeding,

Dok se krvni sudovi skupljaju kako bi smanjili krvarenje,

in a process known as vasoconstriction,

u procesu pod nazivom vazokonstrikcija,

both threats are averted by forming a blood clot.

obe pretnje se eliminišu tako što se stvara krvni ugrušak.

A special protein known as fibrin forms cross-links on the top of the skin,

Poseban protein zvani fibrin stvara veze na vrhu kože

preventing blood from flowing out and bacteria or pathogens from getting in.

i time sprečava krv da teče van a bakterije i patogene da uđu unutra.

After about three hours of this, the skin begins to turn red,

Nakon otprilike tri sata ovog procesa, koža počinje da crveni

signaling the next stage, inflammation.

i time najavljuje sledeću fazu, upalu.

With bleeding under control and the barrier secured,

Kada je krvarenje pod kontrolom i prepreka osirurana,

the body sends special cells to fight any pathogens that may have gotten through.

telo šalje posebne ćelije da se bore sa patogenima koji su možda prošli.

Among the most important of these are white blood cells,

Najbitnije među njima su bela krvna zrnca,

known as macrophages,

zvana makrofagi,

which devour bacteria and damage tissue through a process known as phagocytosis,

koja proždiru bakterije i oštećuju tkivo kroz proces zvani fagocitoza,

in addition to producing growth factors to spur healing.

pored proizvodnje faktora rasta kako bi se podstaklo zarastanje.

And because these tiny soldiers need to travel

A pošto ovi mali vojnici moraju da putuju kroz krv

through the blood to get to the wound site,

kako bi došli do mesta ranjavanja,

the previously constricted blood vessels now expand

do tada suženi krvni sudovi se šire

in a process called vasodilation.

u procesu zvanom vazodilatacija.

About two to three days after the wound,

Oko dva do tri dana nakon nastanka rane,

the proliferative stage occurs, when fibroblast cells begin to enter the wound.

dešava se faza proliferacije, kada fibroblasti kreću da ulaze u ranu.

In the process of collagen deposition,

U procesu taloženja kolagena,

they produce a fibrous protein called collagen in the wound site,

oni proizvode vlaknasti protein na mestu rane, zvani kolagen,

forming connective skin tissue to replace the fibrin from before.

i tako se stvara vezivno tkivo od kože kako bi se zamenio fibrin od pre.

As epidermal cells divide to reform the outer layer of skin,

Kako se ćelije epiderma dele da obnove spoljašnji sloj kože,

the dermis contracts to close the wound.

dermis se skuplja da zatvori ranu.

Finally, in the fourth stage of remodeling,

Konačno, u četvrtoj fazi preoblikovanja,

the wound matures as the newly deposited collagen is rearranged and converted

rana zri dok se sveže nataloženi kolagen raspoređuje i pretvara

into specific types.

u određene tipove.

Through this process, which can take over a year,

Kroz ovaj proces, koji može da traje preko godine,

the tensile strength of the new skin is improved,

zatezna čvrstoća nove kože se poboljšava

and blood vessels and other connections are strengthened.

i krvni sudovi i druge veze se ojačavaju.

With time, the new tissue can reach from 50-80%

Novo tkivo će vremenom dostići od 50 do 80%

of some of its original healthy function,

nekih od svojih normalnih funkcija,

depending on the severity of the initial wound and on the function itself.

u zavisnosti od težine prvobitne rane i same funkcije.

But because the skin does not fully recover,

Ali s obzirom da se koža ne oporavlja potpuno,

scarring continues to be a major clinical issue for doctors around the world.

ožiljci ostaju jedan od najvećih medicinskih problema za doktore u svetu.

And even though researchers have made significant strides

Iako su istraživači postigli znatne pomake

in understanding the healing process,

u razumevanju procesa lečenja,

many fundamental mysteries remain unresolved.

mnoge ključne misterije još nisu rešene.

For instance, do fibroblast cells arrive from the blood vessels

Na primer, da li fibroblasti dolaze iz krvnih sudova

or from skin tissue adjacent to the wound?

ili iz tkiva kože naspram rane?

And why do some other mammals, such as deer,

I zašto neki drugi sisari poput jelena

heal their wounds much more efficiently and completely than humans?

leče svoje rane mnogo efikasnije i potpunije nego ljudi?

By finding the answers to these questions and others,

Pronalazeći odgovore na ove i druga pitanja, jednog dana

we may one day be able to heal ourselves so well that scars will be just a memory.

ćemo možda moći da se izlečimo tako dobro da će ožiljci postati samo sećanje.