Secondary non-specific defences

• How do excretions help to remove pathogens from the body?

  They trap pathogens in mucus and expel them through coughing and sneezing.
• What is the inflammatory response?

  It is a local response to pathogens or damage that causes pain, redness, and swelling.
• What causes pain and redness during inflammation?

  Histamines and cytokines are released, causing blood vessels to dilate.
• What role do cytokines play in the inflammatory response?

  Cytokines cause swelling and pain by increasing blood flow and permeability.
• What can cause a whole body rash?

  Widespread infections can cause a whole body rash.
• Why do many creams to soothe insect bites contain antihistamines?

  Antihistamines suppress the non-specific inflammatory response and prevent swelling.
• What maintains the body temperature of 37°C?

  The hypothalamus maintains the body temperature of 37°C.
• What triggers a fever in the body?

  Cytokines stimulate the brain to raise the body temperature when pathogens invade.
• Why is a fever beneficial?

  A fever inhibits pathogen reproduction by creating an unfavorable environment.
• When does a fever stop being useful and become dangerous?

  When body temperature exceeds 40°C, it can damage cells and enzymes.
• What is the role of phagocytes in the immune response?

  Phagocytes engulf and destroy pathogens that invade the body.
• What are the main types of phagocytes?

  • Macrophages/Monocytes
  • Neutrophils
• What are the different types of white blood cells?

  • Neutrophils
  • Macrophages/Monocytes
  • B lymphocytes
  • T lymphocytes
• Where are B and T lymphocytes made?

  B and T lymphocytes are made in the bone marrow.
• What happens to monocytes in the immune response?

  Monocytes mature into macrophages.
• What is the function of neutrophils?

  Neutrophils are responsible for engulfing and destroying pathogens.
• What is the significance of the inflammatory response?

  The inflammatory response helps to isolate and eliminate pathogens from the body.
• What is chemotaxis in the context of the immune response?

  It is the movement of phagocytes to the site of infection/pathogen
• What is the function of a phagosome?

  It contains enzymes to break down materials/microbes
• What occurs in a phagolysosome?

  It is the fusion of phagosome and lysosome where breakdown of pathogens occurs
• What is the primary function of capillaries in the immune response?

  Rapid action against pathogens
• What are the stages of phagocytosis?

  1. Chemotaxis and adherence of microbe to phagocyte
  2. Ingestion of microbe by phagocyte
  3. Formation of a phagosome
  4. Fusion of the phagosome with a lysosome to form a phagolysosome
  5. Digestion of ingested microbe by enzymes
  6. Formation of residual body containing indigestible material
• What is chemotaxis in the context of phagocytosis?

  The movement of phagocytes towards the site of infection
• What occurs during the ingestion stage of phagocytosis?

  The microbe is engulfed by the phagocyte
• What is formed when a phagosome fuses with a lysosome?

  A phagolysosome is formed
• What is the role of digestive enzymes in phagocytosis?

  They digest the ingested microbe
• What is contained in the residual body formed during phagocytosis?

  Indigestible material
• What is the significance of discharging waste materials in phagocytosis?

  It helps to eliminate indigestible substances from the phagocyte
• How long does it take a neutrophil to engulf and destroy a bacterium?

  10 minutes
• Why does it take macrophages longer to engulf and destroy a bacterium compared to neutrophils?

  Because they undergo a more complex process
• What is the major histocompatibility complex (MHC)?

  It is a complex that combines antigens from pathogens with special glycoproteins in the cytoplasm
• What happens when a macrophage has digested a pathogen?

  It combines antigens from the pathogen's surface membrane with special glycoproteins in the cytoplasm
• What is an antigen-presenting cell?

  It is a cell that moves pathogen antigens to the macrophage's surface membrane
• What is the process that macrophages undergo after digesting a pathogen?

  • Digestion of the pathogen
  • Combination of antigens from the pathogen's surface with glycoproteins
  • Presentation of the MHC complex on the macrophage's surface
• What is the first step in forming an antigen-presenting cell (APC)?

  The macrophage digests a pathogen.
• What does the macrophage combine with the pathogen's antigens during the formation of an APC?

  The macrophage combines the antigens with a special glycoprotein called the major histocompatibility complex (MHC).
• What is the role of the major histocompatibility complex (MHC) in the formation of an APC?

  MHC moves pathogen antigens to the macrophage's own surface membrane.
• What happens to the macrophage after it presents the antigens on its surface?

  The macrophage becomes an antigen-presenting cell (APC).
• How do the antigens presented by the APC affect the immune system?

  The antigens stimulate other cells involved in the specific immune system response.
• What is the overall process of phagocytosis and the formation of an antigen-presenting cell?

  1. Macrophage digests a pathogen.
  2. Antigens from the pathogen combine with MHC.
  3. MHC moves antigens to the macrophage's surface.
  4. Macrophage becomes an antigen-presenting cell (APC).
  5. Antigens stimulate specific immune system response.