Here are the important microbiology questions and answers from Chapter # 8 “Host defense” for exam preparation.

• What is the primary function of the skin in host defense against microbial pathogens?
  a) Temperature regulation
  b) Sensation
  c) Physical barrier
  d) Nutrient absorption
  Answer: c) Physical barrier
• Which of the following is an example of an innate immune response mechanism?
  a) Antibody production
  b) T-cell activation
  c) Phagocytosis
  d) Memory cell formation
  Answer: c) Phagocytosis
• Which type of white blood cell is primarily responsible for the ingestion and destruction of invading microbes?
  a) T cells
  b) B cells
  c) Neutrophils
  d) Platelets
  Answer: c) Neutrophils
• The complement system is a part of the:
  a) Innate immune system
  b) Adaptive immune system
  c) Both innate and adaptive immune systems
  d) None of the above
  Answer: a) Innate immune system
• Which of the following is an example of a specific (adaptive) immune response?
  a) Inflammation
  b) Fever
  c) Antibody production
  d) Skin barrier
  Answer: c) Antibody production
• Immunization with a vaccine primarily activates which branch of the immune system?
  a) Innate immune system
  b) Adaptive immune system
  c) Both innate and adaptive immune systems
  d) None of the above
  Answer: b) Adaptive immune system

• What is the primary function of antibodies in the immune system?
  a) Directly destroy pathogens
  b) Promote phagocytosis
  c) Inhibit complement activation
  d) Regulate cytokine production
  Answer: b) Promote phagocytosis
• Which of the following is an example of a cellular component of the immune system?
  a) Antibodies
  b) Interferons
  c) Natural killer cells
  d) Complement proteins
  Answer: c) Natural killer cells
• Mucous membranes in the respiratory and digestive tracts are part of the host defense mechanism primarily due to:
  a) Antibody secretion
  b) Coughing and sneezing reflexes
  c) Mucus production and ciliary action
  d) Enzyme secretion
  Answer: c) Mucus production and ciliary action
• Which of the following is a mechanism by which pathogens can evade host defenses?
  a) Activation of phagocytes
  b) Production of antibodies
  c) Antigen presentation
  d) Antigenic variation
  Answer: d) Antigenic variation

• What is the primary function of the spleen in the immune system?
  a) Blood clotting
  b) Red blood cell production
  c) Filtering and monitoring blood for pathogens
  d) Digestion of pathogens
  Answer: c) Filtering and monitoring blood for pathogens
• Which type of immune response is typically faster upon re-exposure to a previously encountered pathogen?
  a) Primary immune response
  b) Secondary immune response
  c) Tertiary immune response
  d) Innate immune response
  Answer: b) Secondary immune response
• Which of the following is an example of a chemical barrier in host defense?
  a) Skin
  b) Tears
  c) Lymph nodes
  d) Hair
  Answer: b) Tears
• The process by which immune cells recognize self from non-self is called:
  a) Antigen presentation
  b) Immune memory
  c) Self-tolerance
  d) Immunization
  Answer: c) Self-tolerance
• Which class of antibodies is most abundant in the bloodstream and is the first to be produced during an immune response?
  a) IgA
  b) IgE
  c) IgG
  d) IgM
  Answer: d) IgM
• What is the primary function of cytotoxic T cells in the immune system?
  a) Producing antibodies
  b) Phagocytosis of pathogens
  c) Directly killing infected cells
  d) Regulating inflammation
  Answer: c) Directly killing infected cells

• Which of the following is an example of passive immunity?
  a) Receiving a vaccination
  b) Producing antibodies after an infection
  c) Transferring antibodies from mother to child through breast milk
  d) Activation of T cells
  Answer: c) Transferring antibodies from mother to child through breast milk
• What is the role of the thymus in the immune system?
  a) Producing antibodies
  b) Filtering blood for pathogens
  c) Maturation of T cells
  d) Producing mucus
  Answer: c) Maturation of T cells
• Which of the following is a major function of the lymphatic system in host defense?
  a) Oxygen transport
  b) Nutrient absorption
  c) Drainage of interstitial fluid and transport of immune cells
  d) Regulation of body temperature
  Answer: c) Drainage of interstitial fluid and transport of immune cells
• Immunodeficiency disorders result in:
  a) Enhanced immune responses
  b) Weakened or compromised immune responses
  c) Overproduction of antibodies
  d) Autoimmune diseases
  Answer: b) Weakened or compromised immune responses

• Which of the following is NOT a component of the first line of defense in the immune system?
  a) Skin
  b) Mucous membranes
  c) Fever
  d) Saliva
  Answer: c) Fever
• Which type of white blood cell is primarily responsible for presenting antigens to T cells during an immune response?
  a) Neutrophils
  b) B cells
  c) Macrophages
  d) Natural killer cells
  Answer: c) Macrophages
• The process by which antibodies and complement proteins coat the surface of pathogens, making them easier to be recognized and phagocytosed, is called:
  a) Opsonization
  b) Antigenic variation
  c) Immunization
  d) Autoimmunity
  Answer: a) Opsonization
• Which of the following is an example of a physical barrier in host defense?
  a) Interferons
  b) Cytokines
  c) Cilia in the respiratory tract
  d) Antibodies
  Answer: c) Cilia in the respiratory tract
• Which class of antibodies is involved in allergic reactions and defense against parasites?
  a) IgA
  b) IgG
  c) IgE
  d) IgM
  Answer: c) IgE
• Which of the following is a function of the lymph nodes in the immune system?
  a) Filtering and monitoring blood
  b) Maturation of T cells
  c) Production of red blood cells
  d) Digestion of pathogens
  Answer: b) Maturation of T cells
• Which type of immunity is acquired through vaccination or exposure to a disease-causing pathogen?
  a) Innate immunity
  b) Passive immunity
  c) Natural immunity
  d) Active immunity
  Answer: d) Active immunity
• What is the primary role of helper T cells in the immune system?
  a) Directly kill infected cells
  b) Produce antibodies
  c) Coordinate immune responses
  d) Phagocytose pathogens
  Answer: c) Coordinate immune responses
• Which of the following is an example of a chemical mediator of inflammation?
  a) Antibodies
  b) Histamine
  c) Neutrophils
  d) T cells
  Answer: b) Histamine
• Autoimmune diseases occur when the immune system:
  a) Fails to respond to pathogens
  b) Attacks the body’s own tissues
  c) Is overactive in response to infections
  d) Produces too many antibodies
  Answer: b) Attacks the body’s own tissues

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