CHAPTER 14

• How many ways does the animal body defend itself?

  Five ways
• What is the first line of defense in the animal body?

  Skin
• What role do mucous membranes play in defense?

  They trap and expel harmful particles
• What are some additional physical barriers in animals?

  Scales, feathers, and fur
• What is innate immunity?

  Non-specific defenses present at birth
• What are phagocytes?

  White blood cells that engulf foreign particles
• What is the inflammatory response?

  Localized reaction to tissue damage
• What do natural killer cells do?

  Destroy infected or cancerous cells
• What are interferons?

  Proteins produced in response to viral infections
• What is genetic resistance?

  Natural resistance to diseases due to genetic variation
• What do macrophages do?

  Present antigens to T cells
• What is humoral immunity?

  Involves production of antibodies
• What do B lymphocytes (B cells) do?

  Produce antibodies in response to antigens
• What happens when a lymphocyte encounters an antigen?

  It becomes activated and divides
• What do plasma cells do?

  Produce large amounts of antibodies
• What are memory B cells?

  Cells that respond quickly to re-encountered antigens
• What do cytotoxic T cells (CTLs) do?

  Directly kill infected and cancer cells
• What is the role of helper T cells (Th cells)?

  Activate other immune cells
• How do lymphocytes contribute to tissue repair?

  They release chemicals promoting healing
• What is immunological tolerance?

  Distinguishing between "self" and "non-self" antigens
• How long do B cells typically live?

  A few weeks
• Why is it important to maintain a healthy lifestyle for the immune system?

  It helps the immune system adapt to threats
• What are some natural barriers to infection?

  Skin and self-cleaning processes
• What are self-cleaning processes?

  Coughing, sneezing, and mucous flow
• What is the function of normal flora?

  Protect against harmful pathogens
• How do secretions like sweat and sebum contribute to defense?

  They create a low pH and are bactericidal
• What is opsonization?

  Targeting particles for phagocytosis
• What is chemotaxis?

  Cell migration toward attracted particles
• What occurs during ingestion in phagocytosis?

  Cell engulfs the particle within cytoplasm
• What happens during digestion in phagocytosis?

  Particles are digested by lysosomal enzymes
• Which cells perform phagocytosis?

  Macrophages and neutrophils
• What are nonspecific defenses?

  Defenses that do not discriminate between threats
• What are specific defenses?

  Protect against particular threats
• What are examples of non-specific defenses?

  Physical barriers and phagocytes
• What is inflammation?

  Localized tissue response to injury
• What are the goals of inflammation?

  Repair tissue and prevent pathogen entry
• What sensations are associated with inflammation?

  Pain, redness, swelling, and heat
• What triggers inflammation?

  Destruction of cells by various stimuli
• What is the complement system?

  A series of proteins that destroy pathogens
• How does the complement system function?

  Activates other immune cells and promotes inflammation