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Questions and Answers
Which granulocyte is primarily responsible for the initial response to infections and wound healing?
Which granulocyte is primarily responsible for the initial response to infections and wound healing?
What is the primary function of macrophages after monocytes migrate into tissues?
What is the primary function of macrophages after monocytes migrate into tissues?
Which type of immune cell is classified as the most potent phagocytic cell in tissues?
Which type of immune cell is classified as the most potent phagocytic cell in tissues?
What type of cell is primarily involved in defending against parasitic infections?
What type of cell is primarily involved in defending against parasitic infections?
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Which of the following cells express MHC class II molecules for antigen presentation?
Which of the following cells express MHC class II molecules for antigen presentation?
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What is the primary function of the thymus gland in the immune system?
What is the primary function of the thymus gland in the immune system?
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Which of the following is NOT classified as a peripheral or secondary lymphoid organ?
Which of the following is NOT classified as a peripheral or secondary lymphoid organ?
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What do B lymphocytes require in order to become plasma cells capable of producing antibodies?
What do B lymphocytes require in order to become plasma cells capable of producing antibodies?
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Which molecules are specifically produced by T lymphocytes to help direct the immune response?
Which molecules are specifically produced by T lymphocytes to help direct the immune response?
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What is the role of Major Histocompatibility Complex (MHC) in the immune system?
What is the role of Major Histocompatibility Complex (MHC) in the immune system?
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Which component is primarily responsible for hematopoiesis?
Which component is primarily responsible for hematopoiesis?
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What type of immune cells are produced and mature in the bone marrow?
What type of immune cells are produced and mature in the bone marrow?
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What primarily activates cytotoxic T cells?
What primarily activates cytotoxic T cells?
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Which cytokines are produced by Th2 T-helper cells?
Which cytokines are produced by Th2 T-helper cells?
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What is the primary function of regulatory T cells (Treg)?
What is the primary function of regulatory T cells (Treg)?
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Which type of T-cell carries the CD8 glycoprotein marker?
Which type of T-cell carries the CD8 glycoprotein marker?
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Natural killer (NK) cells are defined by their ability to kill without what?
Natural killer (NK) cells are defined by their ability to kill without what?
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What primarily determines NK cell activation?
What primarily determines NK cell activation?
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What function do memory T cells serve in the immune response?
What function do memory T cells serve in the immune response?
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Which T-cell type is specifically characterized by the presence of CD4 markers?
Which T-cell type is specifically characterized by the presence of CD4 markers?
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What triggers the activation of cytotoxic T cells besides antigen binding?
What triggers the activation of cytotoxic T cells besides antigen binding?
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How does the activation of toxic NK cells typically occur?
How does the activation of toxic NK cells typically occur?
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Study Notes
Immune System Overview
- The immune system is a collection of cells, tissues, organs, and molecules that protect against microorganisms, microbial toxins, and tumor cells.
- Lymphoid tissue and organs are divided into central (primary) and peripheral (secondary).
Central Lymphoid Organs
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Bone Marrow: Located within the central cavity of all bones, responsible for blood cell production (hematopoiesis) and development of myeloid and lymphoid cells.
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Thymus Gland: A small gland behind the sternum, facilitating the development and proliferation of T lymphocytes (T cells), differentiating them into cytotoxic or helper T cells.
Peripheral Lymphoid Organs
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Lymph Nodes: Filter lymph, crucial for immune responses.
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Spleen: Filters blood, involved in immune responses to blood-borne pathogens.
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Mucosa-associated lymphoid tissues (MALT): Including tonsils, adenoids, Peyer's patches, and appendix, these tissues are crucial for defending mucosal surfaces.
Immune System Molecules
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Antibodies (immunoglobulins): Proteins produced by B lymphocytes (plasma cells) that specifically target antigens.
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Lymphokines: Cytokines secreted by T lymphocytes, influencing immune responses through signaling between immune cells.
Immune System Cells
Lymphocytes
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B lymphocytes: Produced and mature in the bone marrow, expressing unique antigen-binding receptors (B cell receptors). Upon antigen exposure and cytokine stimulation, most B cells become plasma cells, which produce antibodies. Some become memory B cells for future encounters.
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T lymphocytes: Produced in bone marrow but mature in the thymus, not producing antibodies. They recognize antigens through cell surface MHC receptors.
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Cytotoxic T cells (CD8+): Recognize antigens presented on MHC I molecules, primarily on virus-infected cells and kill them.
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Helper T cells (CD4+): Crucial for both humoral and cellular immune responses. Recognize antigens presented on MHC II molecules and secrete cytokines to activate B cells and other immune cells.
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Two major types:
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Th1 cells: Produce IFN-γ to activate cytotoxic T cells.
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Th2 cells: Produce IL-4 and IL-5 to activate B cells.
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Regulatory T cells (Treg): Suppress immune responses to prevent overactivity.
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Memory T cells: Recognize antigens from previous encounters, initiating rapid responses upon re-exposure.
Other Cells
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Natural Killer (NK) cells: Large granular lymphocytes capable of killing virus-infected cells or tumor cells without prior sensitization. NK cell activity depends on a balance between activating and inhibitory signals.
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Granulocytes (e.g., neutrophils): First responders to infections, possessing bactericidal activity. Neutrophils accumulate at sites of inflammation and form pus. Eosinophils are involved in parasitic infections, Basophils are involved in allergic reactions.
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Monocytes/Macrophages: Migrate into tissues and differentiate into macrophages, performing phagocytosis and presenting antigens to T cells, essential for initiating specific immune responses.
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Dendritic Cells: Phagocytose antigens and present them to T lymphocytes, facilitating the initiation of adaptive immunity, located in tissues and lymphatic areas.
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Antigen-presenting cells: Macrophages, Dendritic cells, and B cells are crucial for initiating adaptive immunity by capturing, processing, and presenting antigens to T cells.
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Description
Explore the complex structure and function of the immune system, focusing on both central and peripheral lymphoid organs. This quiz covers essential topics such as bone marrow, thymus gland, lymph nodes, and the spleen. Test your knowledge on how these components work together to defend the body against pathogens.
