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Questions and Answers
What role do white blood cells play in the immune system?
What role do white blood cells play in the immune system?
Which of the following is NOT considered a first line of defense in the immune system?
Which of the following is NOT considered a first line of defense in the immune system?
What organelles are used by phagocytes to break apart foreign particles?
What organelles are used by phagocytes to break apart foreign particles?
Which of the following components contributes to the physiological barriers of the immune system?
Which of the following components contributes to the physiological barriers of the immune system?
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What is the main function of phagocytes within the immune system?
What is the main function of phagocytes within the immune system?
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What role does interferon play in the body's defense against viruses?
What role does interferon play in the body's defense against viruses?
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Which of the following describes the primary lymphoid organs involved in the immune system?
Which of the following describes the primary lymphoid organs involved in the immune system?
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What happens during the inflammatory response triggered by injured body cells?
What happens during the inflammatory response triggered by injured body cells?
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What is the primary function of natural killer (NK) cells in the immune response?
What is the primary function of natural killer (NK) cells in the immune response?
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What is the significance of the thymus in the immune system?
What is the significance of the thymus in the immune system?
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What is the primary function of the skin in the immune response?
What is the primary function of the skin in the immune response?
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Which statement about IgM is correct?
Which statement about IgM is correct?
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What role does IgG play in the immune response?
What role does IgG play in the immune response?
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What characterizes the function of memory B cells?
What characterizes the function of memory B cells?
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What is one function of fever in the immune response?
What is one function of fever in the immune response?
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What is the primary role of colostrum in the respiratory tract?
What is the primary role of colostrum in the respiratory tract?
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Which type of T lymphocyte is responsible for activating other immune cells?
Which type of T lymphocyte is responsible for activating other immune cells?
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What distinguishes active immunity from passive immunity?
What distinguishes active immunity from passive immunity?
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Which T cell subtype produces lymphokines that dampen immune responses?
Which T cell subtype produces lymphokines that dampen immune responses?
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In what way do memory T cells enhance the immune response?
In what way do memory T cells enhance the immune response?
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What is the mechanism of action for cytotoxic T cells?
What is the mechanism of action for cytotoxic T cells?
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What is the purpose of a vaccine in relation to active immunity?
What is the purpose of a vaccine in relation to active immunity?
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How does active immunity typically develop?
How does active immunity typically develop?
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Study Notes
The Immune System
- What is the immune system? The body's defense against disease-causing organisms, malfunctioning cells, and foreign particles.
- Components of the immune system: White blood cells (WBCs), phagocytes and lymphocytes, bone marrow, lymph nodes, tonsils, thymus, and spleen.
- First line of defense: Anatomical barriers (skin, mucus membranes), physiologic barriers (pH, fever, enzymes), and the complement system.
White Blood Cells
- Phagocytes: Eat foreign particles by engulfing them.
- Lysosomes: Organelles within phagocytes that break down engulfed particles.
Interferon
- Virus-infected cells release interferon: Interferes with the ability of viruses to attack other body cells.
NK Cells
- Natural killer cells (NK cells): Recognize and attack infected human cells and cancer cells.
Inflammatory Response
- Injured cells release histamine: Leads to capillary dilation, pyrogen release (fever), pain receptor activation, and WBC migration to the infected area.
Immune System Divisions
- Innate Immunity: Inborn, non-specific, poor memory.
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Adaptive Immunity: Acquired (due to exposure), specific, good memory, self-limiting.
- Humoral Immunity: B-cells target bacteria and protozoa.
- Cell-Mediated Immunity: T-cells target viruses and cancer cells.
Organs of the Immune System
- Primary Lymphoid Organs: Where immune cells are produced and mature (bone marrow and thymus).
- Secondary Lymphoid Organs: Where immune cells function (lymph nodes and spleen).
Bone Marrow
- Hematopoiesis: Production of naive B and T cells, other blood cell types (phagocytes, erythrocytes, platelets), and site of B cell maturation.
Thymus
- Bilobed organ: More prominent in younger children.
- Site of T cell maturation: Naive T cells become helper T cells and cytotoxic T cells.
- DiGeorge Syndrome: Congenital absence of the thymus.
Non-Specific Immune Response
- Anatomical barriers: Skin prevents bacterial growth (low pH). Mucosal membranes can be ciliated (e.g., respiratory tract) to expel foreign particles.
- Fever: Has bacteriostatic function and inactivates bacterial enzymes.
Specific Immune Response
Humoral Immunity
- B Lymphocytes: Produced in bone marrow and become plasma cells when activated by a specific antigen.
- Antibodies (Immunoglobulins): Specific shapes allow them to bind to specific molecules (antigens).
- Memory B cells: Provide a faster response to the same pathogen upon re-exposure.
Antibody Types
- IgG: Most common antibody type; crosses the placenta; important in secondary immune responses.
- IgM: First antibody produced in an acute infection.
- IgA: Secretory Ig; found in saliva and mucus membranes (e.g., GIT, respiratory tract), and breast milk.
- IgD: Role unclear.
- IgE: Involved in allergic reactions.
Cell-Mediated Immunity
- T Lymphocytes: Originate in bone marrow, mature in the thymus, and mediate cellular immunity.
T Lymphocyte Types
- Helper T cells (T4 cells): Recognize antigens and activate other immune cells.
- Cytotoxic T cells (Killer T cells): Destroy cells infected by viruses, tumor cells, and transplanted tissues.
- Suppressor T cells: Dampen the immune response.
- Memory T cells: Respond more quickly to previously encountered antigens.
Immunity
- Resistance to disease-causing organisms or harmful substances.
- Natural Immunity: Inherited or inborn.
- Acquired Immunity: Developed after exposure to a pathogen or vaccine.
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Active Immunity: The body produces its own antibodies
- Exposure to the actual disease-causing agent: The body remembers the antigen.
- Vaccination: Deliberate exposure to a killed or weakened form of the antigen, resulting in immunity.
Passive Immunity
- Antibodies are transferred from another source: Short-lived.
- Examples: Antibodies passed from mother to fetus through the placenta or in breast milk.
Vaccine
- A weakened or killed form of a pathogen: Deliberately introduced to the immune system to stimulate an immune response.
- Eradicated or limited many diseases: Such as polio and smallpox.
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Description
Test your knowledge on the immune system, its components, and functions. This quiz covers topics including white blood cells, interferon, NK cells, and the inflammatory response. Perfect for students studying biology or health sciences.
