immunity

• What is active immunity?

  Active immunity is acquired when an antigen enters the body triggering a specific immune response.
• How is active immunity naturally acquired?

  Active immunity is naturally acquired through exposure to microbes.
• How is active immunity artificially acquired?

  Active immunity is artificially acquired through vaccinations.
• What types of cells does the body produce in active immunity?

  The body produces memory cells and plasma cells in both types of active immunity.
• What is the significance of memory cells in active immunity?

  Memory cells provide long-term immunity to the person.
• How long does it take for antibody concentration to increase during the primary response in active immunity?

  It takes one to two weeks for antibody concentration to increase during the primary response.
• What happens during the secondary response to a pathogen in active immunity?

  During the secondary response, antibody concentration increases much faster and is higher than after the first infection or vaccination.
• If a person is vaccinated against a pathogen, what can be expected during a subsequent infection by the same pathogen?

  The antibody concentration will increase much faster during the secondary response.
• How does the antibody response differ between the primary and secondary responses in active immunity?

  The primary response takes longer to increase antibody concentration, while the secondary response is quicker and higher in concentration.
• What is passive immunity?

  Passive immunity is acquired without an immune response.
• Why are antibodies not produced by the infected person in passive immunity?

  Because the person's immune system has not been activated.
• What happens to memory cells in passive immunity?

  There are no memory cells that can produce antibodies in a secondary response.
• If a person is reinfected, what do they need in passive immunity?

  They need another infusion of antibodies.
• Why might passive immunity occur instead of active immunity?

  Because there may not be time to actively acquire immunity.
• What is artificial passive immunity?

  It occurs when people are given an injection or transfusion of antibodies.
• What are the two types of passive immunity?

  Artificial passive immunity and natural passive immunity.
• What is an example of artificial passive immunity in the case of tetanus?

  An injection of antitoxin collected from vaccinated individuals.
• How are antibodies collected for artificial passive immunity?

  They are collected from people whose immune system has been triggered by vaccination.
• What is natural passive immunity?

  It occurs when antibodies are transferred from mother to child.
• How do fetuses receive antibodies in natural passive immunity?

  Through the placenta from their mothers.
• What type of antibody do babies receive from colostrum?

  IgA antibodies.
• What are the key features of passive immunity?

  • Acquired without an immune response
  • No antibody production by the infected person
  • No memory cells for secondary response
  • Requires reinfusion of antibodies upon reinfection
  • Can occur artificially or naturally
• What is the definition of immunity?

  The capacity to recognize and remove foreign material from the body.
• How does the immune system respond to foreign material?

  It mobilizes cells and cell products to remove the foreign material quickly and effectively.
• What is a pathogen?

  A disease-causing micro-organism.
• What is a reservoir in the context of pathogens?

  The place where the pathogen is usually found.
• What does it mean for a disease to be endemic?

  It is always present at low levels in a specific area.
• How is an epidemic defined?

  When the number of cases of a disease increases significantly.
• What are vectors in relation to pathogens?

  Organisms that carry pathogens between other organisms.
• What does it mean for a disease to be infectious?

  It can be passed between hosts.
• What are commensals in the human body?

  Microorganisms that live in or on our bodies causing no harm and benefiting
• How do pathogens enter the human body?

  Through the skin or natural openings
• Why is the skin an effective barrier against microorganisms?

  Due to its thin continuous keratinised layer
• What happens to microorganisms on the skin?

  They can be washed off easily and skin can flake off
• What role does lysozyme play in the eyes?

  It breaks down bacterial cell walls
• When does invasion by pathogens occur?

  When the skin is broken
• How is immunity defined?

  As the capacity to recognize foreign material and mobilize cells to remove it
• What is a pathogen?

  A disease-causing microorganism
• What is a reservoir in the context of pathogens?

  The place where the pathogen is usually found
• What does endemic mean in terms of disease?

  A disease which is always present at low levels