Prática de Shadowing: The Immune System Explained I – Bacteria Infection - Aprenda a falar inglês com vídeo
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Every second of your life you are under attack.
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Billions of bacteria, viruses and fungi are trying to make you their home.
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So our bodies have developed a super complex little army with guards, soldiers, intelligence, weapons factories and communicators to protect you from, well, dying.
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For this video, let's assume the immune system has 12 different jobs.
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For example, kill enemies, communicate, etc. And it has 21 different cells and two protein forces.
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These cells have up to four different jobs.
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Let's assign them.
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Here are the interactions.
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Now let's make this understandable.
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First of all, let's add colors to the jobs.
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Now let's illustrate the cells.
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The central color represents the main job of the cell, while the surrounding ones represent secondary duties.
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Now the immune system looks like this.
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Now the interactions.
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Isn't this complexity just awesome?
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For this video we will only talk about these cells and ignore the rest.
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So what happens in the case of an infection?
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It's a beautiful day when suddenly a wild rusty nail appears and you cut yourself.
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The first barrier of the immune system is breached, your skin.
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Nearby bacteria seize on the opportunity and enter your wound.
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They start using up the body's resources and double their numbers about every 20 minutes.
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At first they fly under the radar, but when a certain bacteria population is reached, they change their behavior and start to damage the body by changing the environment around them.
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The immune system has to stop them as fast as possible.
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First of all, your guard cells, known as macrophages, intervene.
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They are huge cells that guard every border region of the body.
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Most of the time, they alone can suffocate an attack, because they can devour up to 100 intruders each.
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They swallow the intruder hole and trap it inside a membrane.
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Then the enemy gets broken down by enzymes and is killed.
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On top of that they cause inflammation by ordering the blood vessels to release water into the battlefield so fighting becomes easier.
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You notice this as a very mild swelling.
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When the macrophages fight for too long they call in heavy backup by releasing messenger proteins that communicate location and urgency.
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Neutrophiles leave their patrol routes in the blood and move to the battlefield.
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The neutrophiles fight so furiously that they kill healthy cells in the process.
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On top of that, they generate barriers that trap and kill the bacteria.
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They are indeed so deadly that they evolved to commit suicide after five days to prevent them from causing too much damage.
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If this is not enough to stop the invasion, the brain of the immune system kicks in.
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The dendritic cell gets active.
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It reacts to the signals of the soldiers and starts collecting samples from the enemies.
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They rip them into pieces and present the parts on their outer layer.
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Now the dendritic cell makes a crucial decision.
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Should they call for antivirus forces that eradicate infected body cells or an army of bacteria killers?
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In this case, antibacterial forces are necessary.
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It then travels to the closest lymph node in about a day.
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Here billions of helper and killer T cells are waiting to be activated.
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When T cells are born, they go through a difficult and complicated training process, and only a quarter survives.
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The surviving cells are equipped with a specific setup.
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And the dendritic cell is on its way looking for a helper T cell with a setup that's just right.
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It's looking for a helper T cell
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that combines to the parts of the intruders which the dendritic cell has presented on its membrane.
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When it finally finds one, a chain reaction takes place.
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The helper T cell is activated.
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It quickly duplicates thousands of times.
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Some become memory two cells that stay in the lymph node and will make you practically immune against this enemy.
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Some travel to the field of battle to help out.
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And the third group goes on to travel to the center of the lymph node to activate a very powerful weapons factory.
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Like the T-cells, they're born with a specific setup, and when a B-cell and a T-cell with the same setup meet, hell breaks loose.
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The B-cell duplicates rapidly and starts producing millions of little weapons.
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They work so hard that they would literally die from exhaustion very fast.
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Here helper T cells play another important role.
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They stimulate the hard working factories and tell them don't die yet we still need you keep going.
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This also ensures that the factories die if the infection is over so the body doesn't waste energy or hurt itself.
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But what is produced by the B cells?
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You've heard of them of course antibodies.
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Little proteins that are engineered to bind to the surface of the specific intruder.
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There are even different kinds of antibodies that have slightly different jobs.
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The helper T cells tell the plasma cells which type is needed the most in this particular invasion.
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Millions of them flood the blood and saturate the body.
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Meanwhile, at the site of infection, the situation is getting dire.
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The intruders have multiplied in number and start hurting the body.
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Guard and attack cells fight hard, but also die in the process.
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Helper T cells support them by ordering them to be more aggressive and to stay alive longer.
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But without help, they can't overwhelm the bacteria.
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But now the second line of defense arrives.
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Billions of antibodies flood the battlefield and disable lots of the intruders, rendering them helpless or killing them in the process.
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They also stun the bacteria and make them an easy target.
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Their back is built to connect to killer cells so they can connect and kill the enemy more easily.
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are especially good at gnoming up the bacteria which antibodies have attached to.
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Now, the balance shifts.
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In a team effort, the infection is wiped out.
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At this point, millions of body cells have already died.
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No big deal, the losses are quickly replenished.
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Most immune cells are now useless and without the constant signals they commit suicide, so as not to waste any resources.
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But some stay behind, the memory cells.
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If this enemy is encountered ever again in the future, they will be ready for it and probably kill it before you even notice.
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This was a very, very simplified explanation of parts of the immune system at work.
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Can you Can you imagine how complex this system is?
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Even at this level, when we ignore so many players and all the chemistry.
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Life is awfully complicated, but if we take the time to understand it, we always encounter endless wonders and great beauty.
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This bird has magical powers.
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Let's see a demonstration.
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Bring in the latest scientific research.
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Wow, that's a lot of complicated stuff about the immune system and all its cells.
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How could someone possibly understand all of this?
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Incredible!
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This overview is delightful and easy to grasp, but still scientifically accurate.
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Let's make it a bit more difficult.
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Can she make all of evolution visible at a glance?
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This is brilliant!
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You can clearly see the relationships between species and how they evolved.
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And look at those illustrations!
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These posters are ready to be shared with the world.
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These very special pieces of Kurzgesagt are now available on our
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shop along with many other sciencey products all researched with care and created with love by the Burbs with magical powers.
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Every Kurzgesagt product you buy directly funds another moment we get to spend working on our videos.
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Thank you so much for being a part of our story and for making this channel possible.
📺 Mesmo canal
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Vocabulário e dicas de fala para esta lição
Esta aula de conversação de nível C1 usa o vídeo “The Immune System Explained I – Bacteria Infection”. As palavras que mais se repetem: cell, immune, bacteria, helper, intruder. Este vídeo tem 105 frases e 1286 palavras para praticar shadowing. A fala dura 7:33. O falante fala em ritmo natural, cerca de 170 palavras por minuto, próximo de uma conversa do dia a dia. Apenas 80% das palavras estão entre as 3.000 mais comuns do inglês, por isso o vocabulário é exigente.
Vocabulário principal deste vídeo
As 15 palavras mais avançadas do vídeo, com pronúncia e significado:
| Palavra | Pronúncia | Significado |
|---|---|---|
| bacterium substantivo | /bækˈtɪəɹ.ɪəm/ | bactéria |
| helper substantivo | /ˈhɛlpɚ/ | ajudante |
| intruder substantivo | /ənˈtɹudɚ/ | intruso |
| antibody substantivo | /ˈæn.tɪˌbɑ.di/ | anticorpo |
| dendritic adjetivo | /dɛndˈɹɪtɪk/ | dendrítico |
| lymph substantivo | /lɪmf/ | linfa |
| activate verbo | /ˈæktɪˌveɪt/ | ativar |
| battlefield substantivo | /ˈbætəlˌfiːld/ | campo de batalha |
| macrophage substantivo | /ˈmækɹɔʊː.feɪd͡ʒ/ | macrófago |
| duplicate verbo | /ˈd(j)uː.plɪˌkeɪt/ | duplicar |
| evolve verbo | /ɪˈvɑlv/ | desenvolver, elaborar |
| membrane substantivo | /ˈmɛm.bɹeɪn/ | membrana |
| antibacterial adjetivo | antibacteriano | |
| antivirus substantivo | /ˈantɪvʌɪrəs/ | antivírus |
| devour verbo | /dɪˈvaʊɚ/ | devorar |
Phrasal verbs que você vai ouvir
| Palavra | Significado |
|---|---|
| stay behind verbo | ficar para trás |
| wipe out verbo | aniquilar, exterminar |
Frases que vale a pena repetir
Frases curtas e completas do vídeo que você pode usar na conversa do dia a dia:
- First of all, let's add colors to the jobs.
- Isn't this complexity just awesome?
- You've heard of them of course antibodies.
- Let's make it a bit more difficult.
Gramática neste vídeo
As estruturas que o falante mais usa, com as palavras exatas do vídeo:
| Estrutura | No vídeo |
|---|---|
| Voz passiva be + particípio passado — o foco está no que acontece, não em quem faz | is breached · is reached · is killed |
| Present perfect have/has + particípio passado — uma ação passada que ainda importa agora | have developed · has presented · You've heard |
Pronúncia para ficar de olho
O falante usa 6 contrações e formas reduzidas, como can't, doesn't, don't. Diga-as na forma curta, do jeito que você ouve.
- Os sons de “sh” e “zh”: replenish /ɹɪˈplɛn.ɪʃ/, inflammation /ɪnfləˈmeɪ̯ʃən/, illustration /ˌɪləsˈtɹeɪ̯ʃən/, demonstration /dɛmənˈstɹeɪʃən/
- Palavras longas — acerte a sílaba tônica: antibody /ˈæn.tɪˌbɑ.di/, antivirus /ˈantɪvʌɪrəs/, communicator /kəˈmjuːnɪkeɪtə/, eradicate /əˈræd.əˌkeɪt/, furiously /ˈfjʊə̯ɹi.ə̯sli/
Sons difíceis para falantes de português:
- Consoante final — sem acrescentar um “i” depois: dendritic /dɛndˈɹɪtɪk/, activate /ˈæktɪˌveɪt/, node /noʊd/, battlefield /ˈbætəlˌfiːld/, duplicate /ˈd(j)uː.plɪˌkeɪt/
- /l/ final — a língua toca o céu da boca, não vira “u”: neutrophile /ˈnuː.tɹoʊ̯ˌfaɪ̯ɫ/, disable /dɪsˈeɪbəl/, swell /swɛl/
- /h/ — um sopro suave, diferente do “r”: helper /ˈhɛlpɚ/, helpless /ˈhɛlplɪs/
Como praticar com este vídeo
- Ouça o vídeo inteiro uma vez sem falar e anote as palavras que você não conhece.
- Comece na velocidade 0,75×, faça shadowing frase por frase e volte à velocidade normal quando ficar fácil.
- Grave a sua voz e compare com o original, prestando atenção a palavras como bacterium, helper, intruder.
O que é a Técnica de Shadowing?
Shadowing é uma técnica de aprendizado de idiomas com base científica, originalmente desenvolvida para o treinamento de intérpretes profissionais. O método é simples, mas poderoso: você ouve áudio em inglês nativo e repete imediatamente em voz alta — como uma sombra seguindo o falante com 1-2 segundos de atraso. Pesquisas mostram melhora significativa na precisão da pronúncia, entonação, ritmo, sons conectados, compreensão auditiva e fluência na fala.