¿Cómo funciona el Sistema Inmunológico? | Videos Educativos Aula365

Summary

This educational script delves into the human immune system's defense mechanisms against external and internal threats, such as pathogens and tumors. It explains the innate immune response involving cells like granulocytes and monocytes, which transform into macrophages. The adaptive immune response, featuring B and T lymphocytes, is highlighted, detailing how they target specific antigens and provide immunity against future infections. The script also addresses the recurrence of illnesses like the flu, which mutates and evades immunity, unlike diseases like measles that confer lifelong protection after one infection.

Takeaways

• 🛡️ The immune system defends the body against external threats like microorganisms and internal issues such as tumors.
• 🚫 The body's first line of defense includes natural barriers like skin, mucous membranes, and substances like tears and saliva that may contain antibiotics.
• 🔍 If a pathogen bypasses the natural barriers, it encounters innate immune cells that can neutralize and destroy it.
• 🔥 Inflammation and increased temperature at the site of infection can trigger both innate and adaptive immune responses.
• 🧬 Adaptive immune responses are specific and generated for a particular microorganism, preventing future infections from the same pathogen.
• 🔬 Lymphocytes B and T, originating from embryonic cells in the bone marrow, have different functions in the immune response.
• 🔄 Lymphocyte B activation leads to the production of antibodies through plasma cells, which is part of the humoral immune response.
• 🌐 Lymphocyte T activation is responsible for the cellular immune response, requiring direct cell contact and involving helper and cytotoxic T cells.
• 🤒 Some diseases, like measles or rubella, result in lifelong immunity after the first infection, while others like the flu can recur due to antigenic changes.
• 💉 Vaccines provide immunity by introducing a harmless form of the pathogen, allowing the body to prepare a defense without causing the disease.

Q & A

What is the primary function of the immune system?

The immune system's primary function is to defend the body against external and internal threats, such as invading microorganisms and tumors.

What are the natural barriers that the body uses to protect itself from pathogens?

The body's natural barriers include the skin, mucous membranes, and substances like tears and saliva that may contain antibiotics.

How does the non-specific immune response work?

The non-specific immune response involves cells that attack any foreign substance, object, or microorganism that does not belong to the body. This includes cells like granulocytes and monocytes that transform into macrophages in the presence of a pathogen.

What triggers a specific immune response?

A specific immune response is triggered when there is inflammation at the site of infection, which is caused by the swelling and the presence of the pathogen.

How do adaptive immune responses protect against future infections?

Adaptive immune responses, also known as specific immune responses, help prevent future infections by recognizing and remembering specific pathogens, thus providing immunity against them.

What is the origin of lymphocytes B and T, and how do they differ in function?

Both lymphocytes B and T originate from embryonic cells in the bone marrow. If they reach the thymus, they differentiate into T lymphocytes; otherwise, they become B lymphocytes. B lymphocytes are involved in the humoral immune response by producing antibodies, while T lymphocytes are responsible for the cellular immune response, requiring direct cell-to-cell contact.

What happens when a B lymphocyte encounters a pathogen?

Upon encountering a pathogen, a B lymphocyte recognizes and phagocytoses it. If the pathogen is foreign, it triggers an immune response where the B lymphocyte activates, enlarges, and differentiates into plasma cells and memory cells.

What is the role of plasma cells in the immune response?

Plasma cells are responsible for the humoral immune response. They multiply and produce thousands of clones that release protein complexes known as antibodies into the body's fluids.

How do T helper lymphocytes assist in the immune response?

T helper lymphocytes play a crucial role by assisting other lymphocytes. They help activate B cells to produce antibodies and stimulate cytotoxic T cells to kill infected cells.

What is the difference between diseases that cause illness only once and those that can cause illness multiple times?

Diseases that cause illness only once, like measles or rubella, do so because they leave behind memory B cells that recognize the virus, providing immunity. In contrast, diseases like the flu can cause illness multiple times due to antigenic variation, where small changes in the antigen are recognized as a new pathogen, requiring the immune system to start the response anew.

Why is prevention better than cure according to the script?

Prevention is better than cure because it avoids the need to engage the immune system in a potentially harmful and resource-intensive process of fighting off infections. It also reduces the risk of contracting diseases that can have severe or chronic effects.

Outlines

00:00

🛡️ Immune System Defense

The script introduces the immune system and its dual role in defending the body against external threats like microorganisms and internal issues such as tumors. It explains the body's first line of defense, including physical barriers like skin and mucous membranes, and the presence of substances like tears and saliva that have antibacterial properties. If a pathogen breaches these barriers, it encounters innate immune cells like granulocytes and monocytes, which transform into macrophages to neutralize and destroy the invader. The script then delves into the adaptive immune response, highlighting the roles of B and T lymphocytes. B lymphocytes recognize and phagocytize pathogens, leading to the production of antibodies through plasma cells, which is part of the humoral immune response. T lymphocytes are responsible for the cell-mediated response, with helper T cells aiding other lymphocytes and cytotoxic T cells chemically destroying infected cells. The script also touches on the concept of immunity and how some diseases, like measles, confer lifelong immunity after the first infection, while others, like the flu, can recur due to antigenic mutations in the virus.

05:03

🧬 Understanding Recurrent Infections

This section of the script explores why some diseases result in lifelong immunity after the first infection, while others, such as the flu, can cause recurrent infections. It emphasizes the role of memory B lymphocytes in recognizing previous viral infections, thus preventing reinfection with the same virus. The script explains that the flu virus can mutate its antigens, which are the parts of the virus recognized by the immune system. Even a minor change in the antigen can be perceived as a new pathogen, triggering a new immune response. The segment concludes with a reminder of the importance of prevention and encourages viewers to share their body care routines on the Aula365 app.

Keywords

💡Immune System

The immune system is a complex network of cells, tissues, and organs that work together to defend the body against harmful invaders, such as bacteria, viruses, and other pathogens. In the video, it is highlighted as the body's primary defense mechanism, protecting against both external threats like pathogens and internal threats like tumors. The script explains how the immune system is the first line of defense against diseases, initiating responses to protect the body's health.

💡Innate Response

The innate response is a non-specific defense mechanism that the body uses to combat pathogens. It includes physical barriers like skin and mucous membranes, as well as cellular responses from cells like granulocytes and monocytes that can transform into macrophages. The video script mentions that this type of response is the body's first reaction to an invader, attacking any foreign substance that does not belong to the body.

💡Inflammation

Inflammation is part of the body's immune response to harmful stimuli, such as pathogens or damaged cells. It is characterized by redness, heat, swelling, and often pain. In the script, inflammation is described as a localized response that occurs at the site of infection, involving an increase in temperature and swelling, which helps to recruit immune cells to the area and facilitate the healing process.

💡Adaptive Response

The adaptive response, also known as the specific immune response, is a highly specialized and targeted defense mechanism. It involves the production of specific antibodies that can recognize and neutralize particular pathogens. The video explains that adaptive responses are crucial for long-term immunity, as they 'remember' pathogens and can mount a faster and more effective response upon subsequent exposures.

💡Lymphocytes

Lymphocytes are a type of white blood cell that plays a central role in the immune system. They include B cells and T cells, both of which originate from stem cells in the bone marrow. The video script describes how B cells and T cells, despite having the same origin, have different functions in the immune response: B cells are involved in the humoral response by producing antibodies, while T cells are involved in cell-mediated immunity.

💡Antigens

Antigens are molecules, usually proteins or polysaccharides, found on the surface of pathogens that can trigger an immune response. In the video, antigens are described as the parts of a pathogen that are recognized as foreign by the immune system, leading to the activation of lymphocytes and the production of a targeted immune response.

💡Plasma Cells

Plasma cells are a type of B cell that, upon activation, differentiate into antibody-producing factories. They are responsible for the humoral immune response, as described in the script, where they multiply and release large amounts of specific antibodies into the bloodstream to neutralize pathogens.

💡Memory Cells

Memory cells are a special type of lymphocyte that 'remembers' previous encounters with pathogens. They allow for a faster and more effective immune response upon subsequent exposures to the same pathogen. The video script uses the example of having had chickenpox to illustrate how memory B cells can provide long-lasting immunity against future infections.

💡Helper T Cells

Helper T cells are a subset of T cells that play a crucial role in the immune response by coordinating and enhancing the activity of other immune cells. They are mentioned in the script as being responsible for assisting other lymphocytes, which is essential for a robust immune response against pathogens.

💡Cytotoxic T Cells

Cytotoxic T cells are a type of T cell that can directly kill infected or abnormal cells. They are highlighted in the script as part of the cell-mediated immune response, where they destroy cells that are infected with pathogens, such as viruses, thus protecting the body from disease.

💡Antibodies

Antibodies, also known as immunoglobulins, are proteins produced by plasma cells that can recognize and bind to specific antigens. The video script explains that antibodies are a key component of the humoral immune response, where they neutralize pathogens and mark them for destruction by other immune cells.

Highlights

The immune system constantly works to protect the body from external and internal threats.

External threats include invasion by microorganisms, while internal threats can be tumors.

Natural barriers such as skin, mucous membranes, and substances like tears and saliva contain antibiotics.

If a pathogen passes the natural barrier, it encounters cells that try to neutralize and destroy it.

Innate immune responses are non-specific and attack any foreign substance or microorganism.

Granulocytes and monocytes transform into macrophages in the presence of a pathogen.

Specific immune responses are generated against a particular microorganism and are part of the adaptive immune system.

Adaptive immune responses prevent future infections and provide immunity against diseases.

Lymphocytes B and T have the same origin but different modes of action.

Lymphocytes differentiate in the bone marrow and either become B cells in the spleen or T cells in the thymus.

B lymphocytes recognize and phagocytose pathogens, triggering an immune response.

The part of the cell or capsid recognized as foreign by the lymphocyte is called an antigen.

After phagocytosis, B lymphocytes activate, differentiate into plasma cells and memory cells.

Plasma cells produce and release antibodies, which are part of the humoral immune response.

T lymphocytes are responsible for the cellular immune response, requiring direct cell contact.

Helper T lymphocytes assist other lymphocytes, while cytotoxic T lymphocytes chemically destroy infected cells.

Some diseases are suffered only once due to the body's memory of the antigen.

The flu can be recurrent because the virus's antigen mutates, making it a new pathogen.

Prevention is better than cure, emphasizing the importance of health care and awareness.

Transcripts

¿Recuerdas las última vez que te enfermaste?

Tu cuerpo, todo el tiempo, trata de protegerte.

Mira cómo.

La clase pasada hicimos una introducción al sistema inmune.

¿Recuerdan qué importancia tiene este sistema?

Nos defiende de agresiones externas e internas.

Por ejemplo, externas puede ser la invasión de un microorganismo...

...e interna, de tumores.

¡Muy bien!

Supongamos que un microorganismo patógeno quiere invadir nuestro cuerpo.

Primero se encuentra con barreras naturales como la piel, las mucosas y cierta sustancias,

como las lágrimas o la saliva que pueden tener antibióticos.

¿Y si logra pasar esta barrera natural?

Si puede pasar, se encuentra con células que intentarán neutralizarlo y destruirlo.

Este tipo de respuesta es inespecífica...

...porque estas células atacarán a cualquier sustancia, objeto o microorganismo que no pertenezca al propio cuerpo.

También se las conoce como innatas, y están producidas por varios tipos de células,

como los granulocitos y los monocitos, que en presencia del patógeno se transforman en macrófagos.

¿Cuando la respuesta es específica?

Luego, en el lugar de la infección se forma una inflamación con aumento de temperatura,

mientras esto ocurre, la hinchazón y la presencia del propio microorganismo patógeno desdencadenan, además, otro tipo de respuesta...

...esta vez, la específica, ya que es una respuesta generada para ese microorganismo en particular.

¿Y qué función tienen las respuestas específicas?

Este tipo de respuestas específicas, también conocidas como respuestas adaptativas,

en realidad son las verdaderas respuestas inmunes.

Las mismas previenen futuras infecciones contra muchas de las enfermedades que padecemos.

Es decir, nos inmuniza contra ataques futuros de estas enfermedades.

Este tipo de respuestas tienen como protagonistas a dos tipos celulares que tienen el mismo origen pero distinta forma de acción.

Los linfocitos B y los linfocitos T.

¿Cómo es que tienen el mismo origen pero trabajan de manera diferente?

Ambos tipos de linfocitos provienen de células embrionarias en la médula ósea.

Si estas células llegan al timo, se diferenciarán en linfocitos T, de lo contrario, serán linfocitos B.

¿Y qué hace cada uno de estos linfocitos?

Si un linfocito B se encuentra con uno de un organismo patógeno lo reconoce y lo fagocita.

Recorren el cuerpo constantemente monitoreando cada una de estas células.

Si encuentra que alguna de las células no presenta las proteínas que le son propias,

o alguna parte de su membrana o cápside no son reconocidas como propias, se desencadena la respuesta inmune.

A esta parte de la célula extraña o cápside que el linfocito reconoce como extraña se le llama antígeno.

¿Qué sucede si el linfocito logra fagocitar al cuerpo extraño?

Una vez que el linfocito fagocitó al cuerpo extraño comienza su activación,

es decir que de desarrolla en tamaño y se diferencia en dos tipos de células.

Unas llamadas plasmocitos y otras células de memoria.

Los plasmocitos, a su vez, se dividen repetidas veces creando miles de clones que liberan unos complejos proteínicos llamados anticuerpos.

A este tipo de respuesta inmune, en donde la acción se ejerce liberando anticuerpos a los humores del organismo,

se la llama respuesta humoral.

¿Y qué sucede con los linfocitos T?

Los linfocitos T son responsables de la respuesta celular, porque necesitan el contacto directo entre células.

Hay linfocitos T helper, que se encargan de ayudar a otros linfocitos.

También están los linfocitos T citotóxicos, que destruyen químicamente a las células que estén infectadas.

Profe, ¿o sea que alguanas enfermedades sólo las sufrimos una vez?

Exacto, Aulis. Pero otras como la gripe pueden ser recurrentes.

No sé qué me sucede, pero es la tercera vez en el año que estoy con gripe.

Pero, ¿por qué te preocupa? La gente puede engriparse varias veces.

Eso no es algo raro.

Lo que me preocupa es que la gripe es una enfermedad causada por un microorganismo.

Cuando un organismo extraño entra en nuestro cuerpo hay un sistema de defensa.

Claro, el sistema inmune responde y trata de eliminarlo.

Pero resulta que hay enfermedades que sólo se dan una vez, no se repiten, como las paperas o la rubéola.

Hace unos meses Santiago se enfermó de paperas, yo sí pude ir porque mi mamá me dijo que había tenido paperas,

y no había riesgo de que me contagiara.

Yo tenía linfocitos B de memoria que recordaban que había tenido en mi organismoe el mismo virus,

pero tú no habías tenido y podrías enfermarte.

Entonces, la pregunta es ¿por qué en algunos casos te enfermas una y otra vez, y en otros sólo una vez?

Con la gripe no pasa lo mismo porque tiene diferente antígeno.

Es el mismo virus de la gripe pero su antígeno cambiado por mutaciones.

¡Muy bien, Mati! ¡Eso es!

Un cambio, por pequeño que sea en el antígeno, es reconocido como un nuevo patógeno,

y de vuelta todo el proceso de nuevo.

Siempre es mejor prevenir que curar.

No te olvides de descargar la app de Aula365 y respóndenos en los comentarios:

¿De qué manera cuidas tu cuerpo?

¡Adiós!