Oxygen’s surprisingly complex journey through your body - Enda Butler

Prevoditelj: Irma Komljenović Recezent: Ivan Stamenković

You breathe in about 17,000 times per day.

Udahneš oko 17 000 puta dnevno.

It's a process you rarely think about,

To je proces o kojem rijetko razmišljaš,

no iza scene odvija se ogroman koordinirani rad.

but behind the scenes, a huge coordinated effort is playing out.

Your vital organs,

Tvoji vitalni organi,

the gut,

želudac,

brain,

mozak,

bones,

kosti,

pluća,

lungs,

blood,

krv

and heart

i srce

work together to sustain your life

zajedno rade kako bi te održali na životu

by delivering oxygen to tissues throughout your body.

raznošenjem kisika do tkiva po cijelom tvom tijelu.

Most of our cells need oxygen

Većini naših stanica potreban je kisik

because it's one of the key ingredients of aerobic respiration.

jer je jedan od ključnih sastojaka staničnog disanja.

That's the process that produces a molecule called ATP,

To je proces u kojem se stvara molekula ATP-a,

which our cells use to power their many incredible functions.

koju naše stanice koriste za pokretanje svojih mnogih iznimnih funkcija.

But getting oxygen throughout our bodies is a surprisingly difficult task.

No, dobivanje kisika po cijelom tijelu iznenađujuće je težak zadatak.

Gas enters cells by diffusing in from their surroundings.

Plin ulazi u stanice difuzijom iz okoline,

And that only happens efficiently over tiny distances.

a to se uspješno događa samo preko malih udaljenosti.

So for oxygen to reach the cells within our bodies,

Kako bi kisik dospio do stanica u našem tijelu,

it needs a transportation network.

potrebna mu je prometna veza.

This is where our 20 trillion red blood cells come in.

Ovdje u igru ulazi oko 20 bilijuna naših crvenih krvnih stanica.

Each one contains about 270 million oxygen-binding molecules of hemoglobin,

Svaka od njih sadrži oko 270 milijuna molekula hemoglobina, koji veže kisik

which is what gives blood its scarlet hue.

i krvi daje njenu grimiznu boju.

To make these cells, the body uses raw materials

Kako bi napravilo te stanice, tijelo koristi sirove materijale

that become available from the food we eat.

koje dobivamo iz hrane koju jedemo.

So in some ways, you could say that oxygen's journey through the body

Na neki način, moglo bi se reći da putovanje kisika kroz tijelo

really begins in the gut.

zapravo počinje u želucu.

Here, in an amazing display of mechanical and chemical digestion,

Ovdje, kroz procese kemijske i mehaničke razgradnje,

food gets broken down into its smallest elements,

hrana biva razgrađena na najsitnije elemente

like iron, the building block of hemoglobin.

poput željeza, sastavnice hemoglobina.

Iron is carried through the cardiovascular system

Željezo krvožilnim sustavom biva prenošeno

to the body's hematopoietic tissue.

do hematopoetskog tkiva tijela.

This tissue is the birthplace of red blood cells,

Iz tog tkiva nastaju crvene krvne stanice,

and it can be found enclosed within our bone marrow cavities.

a može ga se naći u šupljinama za koštanu srž.

Bubrezi reguliraju našu razinu crvenih krvnih stanica

The kidneys regulate our levels of red blood cells

through the release of erythropoietin,

lučenjem eritropoetina,

a hormone which causes marrow to increase production.

hormona zbog kojega koštana srž povećava proizvodnju.

Our bodies churn out roughly 2.5 million red blood cells per second,

Naša tijela stvaraju oko 2.5 milijuna crvenih krvnih stanica po sekundi,

a number equivalent to the entire population of Paris,

broj jednak broju stanovnika Pariza,

so that oxygen that makes it to the lungs will have ample transportation.

kako bi kisik koji dospijeva do pluća imao dostatan prijevoz.

But before oxygen can even reach the lungs,

Prije no što kisik može dospjeti do pluća,

the brain needs to get involved.

mozak se mora uplesti.

The brainstem initiates breathing

Moždano deblo inicira disanje

by sending a message through your nervous system,

slanjem poruke kroz tvoj živčani sustav,

all the way to muscles of the diaphragm and ribs.

sve do mišića rebara i dijafragme.

This causes them to contract,

To uzrokuje njihovo skupljanje,

thus increasing the space inside the rib cage,

povećavajući prostor u prsnom košu,

which allows the lungs to expand.

zbog čega se pluća mogu proširiti.

That expansion drops your lungs internal air pressure,

Zbog tog proširenja pada unutarnji tlak tvojih pluća,

making air rush in.

zbog čega zrak može ući.

It's tempting to think of our lungs as two big balloons,

Primamljivo je pluća zamišljati kao dva velika balona,

but they're actually a lot more complicated than that.

no ona su puno složenija od toga.

Here's why.

Evo zašto.

Crvene krvne stanice u žilama unutar tvojih pluća

The red blood cells in the vessels within your lungs

can only pick up oxygen molecules that are very close to them.

mogu pokupiti samo molekule kisika koje su im jako blizu.

If our lungs were shaped like balloons,

Da su nam pluća oblikovana kao baloni,

air that was not in direct contact with the balloon's inner surface

zrak koji nije u direktnom kontaktu s unutarnjom površinom balona

couldn't diffuse through.

ne bi mogao difundirati preko nje.

Luckily, our lungs' architecture ensures that very little oxygen is wasted.

Srećom, arhitektura naših pluća osigurava vrlo maleno traćenje kisika.

Their interior is divided into hundreds of millions

Njihova je unutrašnjost podijeljena na stotine milijuna

of miniature balloon-like projections called alveoli

minijaturnih nastavaka sličnih balonima, alveola,

that dramatically increase the contact area

koji drastično povećavaju dodirnu površinu

to somewhere around 100 square meters.

do oko 100 kvadratnih metara.

The alveolar walls are made of extremely thin flat cells

Stijenke alveola napravljene su od iznimno tankih plosnatih stanica

that are surrounded by capillaries.

koje su okružene kapilarama.

Together, the alveolar wall and capillaries make a two-cell thick membrane

Stijenke alveola i kapilare zajedno čine membranu debelu dvije stanice

that brings blood and oxygen close enough for diffusion.

koja krv i kisik zbliži dovoljno za difuziju.

These oxygen-enriched cells are then carried from the lungs

Ove su kisikom obogaćene stanice onda prenesene do pluća

through the cardiovascular network,

krvožilnim sustavom,

a massive collection of blood vessels that reaches every cell in the body.

ogromnom skupinom krvnih žila koje dospijevaju do svake stanice u tijelu.

If we laid this system out end to end in a straight line,

Kad bismo poredali taj sustav od kraja do kraja u ravnu liniju,

the vessels would wrap around the Earth several times.

žile bi se mogle nekoliko puta omotati oko Zemlje.

Propelling red blood cells through this extensive network

Za pokretanje crvenih krvnih stanica kroz taj dugački sustav

requires a pretty powerful pump,

potrebna je prilično snažna pumpa,

and that's where your heart comes in.

pa tu u igru ulazi tvoje srce.

The human heart pumps an average of about 100,000 times per day,

Ljudsko srce pumpa krv prosječno 100 000 puta dnevno,

and it's the powerhouse that ultimately gets oxygen where it needs to go,

što omogućuje kisiku da dospije gdje treba stići,

completing the body's team effort.

upotpunivši timski rad tijela.

Just think - this entire complex system is built around the delivery

Samo razmisli - cijeli je ovaj složeni sustav izgrađen zbog raznošenja

of tiny molecules of oxygen.

sićušnih molekula kisika.

If just one part malfunctioned, so would we.

Kada bi se samo jedan dio pokvario, i mi bismo.

Breathe in.

Udahni.

Your gut, brain, bones, lungs, blood, and heart

Tvoj želudac, mozak, kosti, pluća, krv i srce

are continuing their incredible act of coordination that keeps you alive.

nastavljaju svoj iznimni koordinirani rad koji te održava na životu.

Breathe out.

Izdahni.