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Bo nauka nie musi być nudna!
I. Read the text and do the exercises below. Przeczytaj tekst i wykonaj ćwiczenia
Regrowing limbs
A salamander’s limbs are smaller and a bit slimier than those of most people, but otherwise
they are not that different from their human counterparts. The salamander limb is covered
with skin, and inside it is composed of a bony skeleton, muscles, ligaments, tendons, nerves
and blood vessels.
Yet a salamander’s limb is unique in the world of vertebrates in that it can regrow from a
stump after an amputation. An adult salamander can regenerate a lost arm or leg this way over
and over again, regardless of how many times the part is amputated. Frogs can rebuild a limb
during tadpole stages when their limbs are first growing out, but they lose this ability in
adulthood. Even mammalian embryos have some ability to replace developing limb buds, but
that capacity also disappears well before birth. Indeed, this trend toward declining
regenerative capacity over the course of an organism’s development is mirrored in the
evolution of higher animal forms, leaving the lowly salamander as the only vertebrate still
able to regrow complex body parts throughout its lifetime.
Humans have long wondered how the salamander does that. How does the regrowing part of
the limb “know” how much limb is missing and needs to be replaced? Why doesn’t the skin at
the stump form a scar to seal off the wound as it would in humans? How can adult salamander
retain the embryonic potential to build an entire limb multiple times? Biologists are closing in
on the answers to those questions. And if we can understand how the regeneration process
works in nature, we hope to be able to trigger it in people to regenerate amputated limbs, for
example, and transform the healing of other major wounds.
The human body’s initial responses to such a serious injury are not that different from those
of a salamander, but soon afterward the human and amphibian woundhealing strategies
diverge. Ours results in a scar and amounts to a failed regeneration response, but several signs
indicate that humans do have the potential to rebuild complex parts. The key to making that
happen will be tapping into our latent abilities so that our own wound healing becomes more
salamanderlike. For this reason, our research first focused on the experts to learn how it is
done.
Lessons from the Salamander
When the tiny salamander limb is amputated, blood vessels in the remaining stump contract
quickly, so bleeding is limited, and a layer of skin cells rapidly covers the surface of the
amputation site. During the first few days after injury, this socalled wound epidermis
transforms into a layer of signalling cells, which is indispensable for successful regeneration.
In the meantime, cells migrate across the amputation surface to meet at the centre of the
wound. There they proliferate to form an aggregation of cells that will become the new limb.
 Bo nauka nie musi być nudna!
Many years ago studies in the laboratory of our colleague Susan V. Bryant at the University
of California, Irvine, demonstrated that the cells are equivalent to the cells in the developing
limb of the salamander embryo. An important implication of this discovery was that the same
genetic program is involved in both situations, and because humans make limbs as embryos,
in principle we should already have the necessary programming to regenerate them as adults,
too. Now, as we watch a salamander grow back an arm, we are no longer quite as mystified
by how it happens. Soon humans might be able to harness this truly awesome ability
ourselves, replacing damaged and diseased body parts.
SCIENTIFIC AMERICAN
1.
Match the words from the text with their translations. Połącz wyrazy z tekstu z
ich tłumaczeniem
limbs
blizna
slim
cały
counterpart
dorosłość
ligament
kijanka
tendon
kikut
vessels
kończyny
vertebrates
kręgowce
stump
kurczyć się
tadpole
naczynia
adulthood
namnażać się
mammalian
naskórek
buds
niezastąpiony
capacity
niezwykły
declining
odpowiednik
seal
rozchodzić się
tissue
ścięgno
retain
ssaczy
entire
szczupły
trigger
tkanka
diverge
ujarzmić
scar
utajony
latent
warstwa
contract
wiązadło
epidermis
zachować
layer
zanikający
indispensable
zapoczątkować
proliferate
zasada
principle
zasklepić
harness
zawiązki
awesome
zdolność
Bo nauka nie musi być nudna!
2.
Read the text again and choose the best answers. Przeczytaj ponownie tekst i
wybierz właściwe odpowiedzi.
1.
The limbs of people and salamanders
a.
differ greatly
b.
are identical
c.
are not very different
2.
Salamanders’ limbs are unique because
a.
they are covered with skin
b.
they can grow back only ones
c.
they can grow back many times
3.
Frogs’ limbs have the same ability as salamanders’
a.
all life
b.
at the beginning of life
c.
at the end of life
4.
Scientists study this phenomenon
a.
to regenerate amputated limbs of humans
b.
to preserve salamanders
c.
to produce skin
5.
Susan V. Bryant found
a.
that humans already have the necessary potential to regrow limbs
b.
that humans grow limbs as embryos
c.
how to regenerate limbs in adult humans
II. Idioms with parts of the body
1.
Match the idioms with their meanings. Połącz idiomy z ich znaczeniami
to turn a blind eye to something
to be clumsy
to be all fingers and thumbs
to be feeling depressed
to be all ears
to be very busy
to keep a straight face
to feel so emotional that you can’t speak
to be run off one’s feet
to get scared
to give someone a hand
to help someone
to pull someone’s leg
to listen carefully
to be down in the mouth
to pretend not to see something
to have a lump in one’s throat
to tease someone
to get cold feet
to try not to laugh
Bo nauka nie musi być nudna!
2.
Complete the sentences with the correct idioms. Uzupełnij zdania właściwymi
idiomami
1.
Sarah couldn’t do her homework but her mother
………….. her a hand
2.
After his wife’s death Tom is a bit
down in ……………..
3.
I would help you to wash the dishes but I’m afraid I would break it all as
I’m all
……………………………
4.
She talked such nonsense during the lecture that it was difficult to
keep a ………. face
5.
He wanted to ask Kate to marry him but he
got ………………..
just before the dinner
6.
If you want to explain yourself
I’m …………………
7.
I can’t help you with that right now! Can’t you see that I’m
run off ……………..
8.
I
had a lump …………………
when I saw my son perform in the nursery school
9.
She always
turns a ……………….
to whatever problems her beloved son causes
10.
Don’t believe everything he tells you, most of the times he is just
pulling …………..
Key
I.
1.
limbs
kończyny
slim
szczupły
counterpart
odpowiednik
ligament
wiązadło
tendon
ścięgno
vessels
naczynia
vertebrates
kręgowce
stump
kikut
tadpole
kijanka
adulthood
dorosłość
mammalian
ssaczy
buds
zawiązki
capacity
zdolność
declining
zanikający
seal
zasklepić
tissue
tkanka
retain
zachować
entire
cały
Bo nauka nie musi być nudna!
trigger
zapoczątkować
diverge
rozchodzić się
scar
blizna
latent
utajony
contract
kurczyć się
epidermis
naskórek
layer
warstwa
indispensable
niezastąpiony
proliferate
namnażać się
principle
zasada
harness
ujarzmić
awesome
niezwykły
2.
1.
c
2.
c
3.
b
4.
a
5.
a
II.
1.
to turn a blind eye to something
to pretend not to see something
to be all fingers and thumbs
to be clumsy
to be all ears
to listen carefully
to keep a straight face
to try not to laugh
to be run off one’s feet
to be very busy
to give someone a hand
to help someone
to pull someone’s leg
to tease someone
to be down in the mouth
to be feeling depressed
to have a lump in one’s throat
to feel so emotional that you can’t speak
to get cold feet
to get scared
2.
11.
Sarah couldn’t do her homework but her mother
gave her a hand
12.
After his wife’s death Tom is a bit
down in the mouth
13.
I would help you to wash the dishes but I’m afraid I would break it all as
I’m all
fingers and thumbs
14.
She talked such nonsense during the lecture that it was difficult to
keep a straight face
15.
He wanted to ask Kate to marry him but he
got cold feet
just before the dinner
16.
If you want to explain yourself
I’m all ears
17.
I can’t help you with that right now! Can’t you see that I’m
run off my feet
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