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There are a lot of things that can harm us.

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There are many organisms around our world that can come inside our body and kill us.

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Why do not die straight ahead after we are born?

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Because we have ways of defending ourselves. Let's go into study them.

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There could be some artificial way to defend ourselves, like the science of medications,

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but our body has its own defensive system. Let's see it.

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Number two, how the body defends itself.

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We have studied many different systems and organs in our body.

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We have studied the digestive system, respiratory system, nervous system, endocrine system, respiratory system.

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Now we're going to study another one related with the defense of our body, immune system.

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Get ready to copy the definition.

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Immune system, set of defense mechanisms that provide human body with resistance to infections caused by pathogens

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There are two ways that the immune system has to defend ourselves

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The first one we are going to study is the innate immunity

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This innate immunity is the immunity that we have from birth

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before we are born and when we are given birth we develop this innate immunity in this innate

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immunity there are external defenses that we have already studied most of them we started with our

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skin we said that our skin was the outer part of our body that was the first way of defending

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our body. We have a way, the different layers of skin, which are going to be a barrier against

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external microorganisms. We have also mucous membrane. When we talk, for example, about the

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trachea, we say that it has some mucous surrounding it and that prevents the infection from getting

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inside our body bodily secretion tears mucus those secretions are going to help when it comes to

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a way to get inside our body we for example we get some dust inside our eye we're going to cry

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and these tears are going to get the things out of the eye and natural bacterial flora for example

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we say that inside the large intestine we have some bacteria that were very important for the

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digestion and to help us with making the feces and with the defense of that part of our body

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but also on our skin there are millions trillions of bacteria that are going to help to maintain it

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healthily do you know for example that when we are born we get the bacteria from our mothers

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when we have a natural birth not a cesarean natural birth we get the bacteria from the vagina

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and those bacteria from our mother are going to get inside our body and they are going to be the

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first bacteria that are going to colonize us and they are going to help with the defense of the

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the body also with the breastfeeding the babies are going to get these bacteria healthy and are

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going to have less infections there are also some cells which their duty is to eat rubbish basically

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which are called the phagocytes in spanish we call it macrophagos and they are white blood

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cells that are going to take all the different bacteria all the different viruses that are

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inside our body, cells which are, for example, dangerous cells because they are cancerous cells

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or tumoral cells, and they are going to take them out of the body. So, what are the phagocytes?

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Copy definition, white blood cells that capture pathogens by means of pseudopedia and digestion.

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One important reaction in this innate immunity is the inflammatory reaction.

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Why? Imagine that we get a cut and we start bleeding.

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All the different processes that are taking place on our skin are part of the inflammatory response.

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You have a drawing in the aula virtual which you have to make here.

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underneath this information, no you cannot print it and just glue it, no you can copy it but do not

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print it and write all the information related to the inflammatory response here. The acquired

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immunity comparing with innate immunity is an immunity that we get throughout our life and it's

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very very specific to the microorganism that is going to infect us this specific reaction is

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taking place by the lymphocytes lymphocytes are also white blood cells but these white cells are

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very very specific to the virus or the bacteria that is inside to our body and they develop the

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humoral immune response that to understand this humoral immune response you are going to

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make a couple of drawings that appear in the aula virtual remember do not print it okay just

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you can copy it but do not print and glue so make the drawings underneath here

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and we'll explain it later in class this is how the body defends itself as you can see there are

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very different elements involved in this situation remember to make good drawings with all the

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the different information there with different colors and see you next day