5.4
Respuesta Inflamatoria I: Vascular y Celular
La respuesta inflamatoria es la defensa del cuerpo contra infecciones, lesiones o irritaciones por bacteria, trauma, toxinas o calor. La inflamación a…
La respuesta inflamatoria es un mecanismo de defensa del cuerpo contra infecciones, lesiones o irritaciones.
Puede ser aguda, que dura días o semanas, o crónica, que dura de varios meses a años.
La inflamación ayuda a identificar y destruir patógenos y elimina los elementos tisulares dañados para que el cuerpo pueda sanar.
Esta respuesta se observa a nivel vascular y celular. Ambos son componentes cruciales del proceso inflamatorio agudo.
En la etapa vascular, los pequeños vasos sanguíneos cerca del sitio de la lesión se contraen inicialmente para evitar la pérdida de sangre.
Las arteriolas y vénulas que suministran sangre a esa área se dilatan, aumentando el flujo sanguíneo y causando enrojecimiento y calor locales.
Además, la liberación de mediadores celulares, como histamina, bradicinina y prostaglandinas, en el área lesionada aumenta la permeabilidad vascular a los líquidos ricos en proteínas y células inmunitarias, lo que causa hinchazón, dolor y pérdida de la función.
Durante la etapa celular, los glóbulos blancos, o WBC, pasan a través de los vasos sanguíneos y se precipitan al sitio de la lesión, lo que provoca un aumento en el recuento general de leucocitos.
Los glóbulos blancos, al igual que los neutrófilos y los monocitos, engullen patógenos e ingieren restos celulares y materiales extraños. Como resultado de la fagocitosis del patógeno, se liberan pirógenos, causando fiebre.
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Q1: What is the inflammatory response and why does the body trigger it?
The inflammatory response is a defense mechanism against infection, injury, or irritation from bacteria, trauma, toxins, or heat. It helps locate and destroy pathogens while removing damaged tissue elements to promote healing. This response occurs at both vascular and cellular levels, with fluid, blood products, and nutrients migrating to the injured area, resulting in redness, heat, swelling, pain, and loss of function.
Q2: What happens to blood vessels during the vascular stage of inflammation?
During the vascular stage, small blood vessels near the injury site initially constrict to prevent blood loss. The arterioles and venules then dilate, increasing blood flow and causing local redness and heat. Cell mediators like histamine and bradykinin are released, increasing vascular permeability and allowing protein-rich fluids to flow into the area, causing swelling and pain.
Q3: How do white blood cells respond during the cellular stage of inflammation?
During the cellular stage, white blood cells, including neutrophils and monocytes, pass through blood vessels and rush to the injury site, increasing overall WBC count. These cells engulf pathogens through phagocytosis and ingest cell debris and foreign material. This phagocytic activity releases pyrogens from bacterial cells, which trigger fever as part of the systemic inflammatory response.
Q4: What role do cell mediators play in the inflammatory response?
Cell mediators such as histamine, bradykinin, and prostaglandins are released in the injured area during inflammation. These mediators increase vascular permeability, allowing protein- and immune-cell-rich fluids to escape blood vessels and enter surrounding tissue. This fluid accumulation causes the characteristic swelling, pain, and temporary loss of function associated with acute inflammation.
Q5: How long can inflammation last and what are the different types?
Inflammation can be acute, lasting days or weeks, or chronic, lasting several months to years. Acute inflammation is the initial response to injury or infection, characterized by vascular and cellular changes. Chronic inflammation represents a prolonged response when the body cannot fully resolve the initial insult, potentially leading to tissue damage and systemic complications.
Q6: What systemic signs indicate that inflammation is occurring throughout the body?
Systemic inflammation produces signs beyond the local injury site, including fever, increased white blood cell count, malaise, anorexia, nausea, and vomiting. Lymph node enlargement may also occur as lymphoid tissues respond to infection. In severe cases, organ failure can develop, indicating that the inflammatory response has become widespread and potentially harmful.
Q7: Why does fever develop as part of the inflammatory response?
Fever develops when white blood cells engulf pathogens through phagocytosis during the cellular stage of inflammation. This phagocytic activity releases pyrogens from bacterial cells, which are fever-inducing substances. Pyrogens circulate through the bloodstream and act on the body's temperature-regulating center, raising the set point and causing fever as part of the systemic inflammatory defense.