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Questions and Answers
What is the primary role of opsonins in the immune response?
What is the primary role of opsonins in the immune response?
Which of the following correctly describes the characteristics of innate immunity?
Which of the following correctly describes the characteristics of innate immunity?
What is the role of dendritic cells in the immune system?
What is the role of dendritic cells in the immune system?
Which cell type matures in the thymus gland?
Which cell type matures in the thymus gland?
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What is the function of interferons in the context of innate immunity?
What is the function of interferons in the context of innate immunity?
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What is a primary function of the immune response?
What is a primary function of the immune response?
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Which of the following are considered infectious agents?
Which of the following are considered infectious agents?
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How do intracellular pathogens like some viruses replicate?
How do intracellular pathogens like some viruses replicate?
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What is the role of the inflammatory response in the immune system?
What is the role of the inflammatory response in the immune system?
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Which type of infection is associated with intracellular replication?
Which type of infection is associated with intracellular replication?
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What distinguishes extracellular pathogens from intracellular ones?
What distinguishes extracellular pathogens from intracellular ones?
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Which of these statements about the immune system is correct?
Which of these statements about the immune system is correct?
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What is the role of soluble factors like antibodies in the immune response?
What is the role of soluble factors like antibodies in the immune response?
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What is considered the most important first line of defense in the immune system?
What is considered the most important first line of defense in the immune system?
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Which of the following components does NOT contribute to the inflammatory response?
Which of the following components does NOT contribute to the inflammatory response?
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Which type of immunity is described as being natural or native and is ready for rapid response?
Which type of immunity is described as being natural or native and is ready for rapid response?
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Which of the following statements about phagocytes is true?
Which of the following statements about phagocytes is true?
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What role does the microbiome play in the immune system?
What role does the microbiome play in the immune system?
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Which of the following is NOT a characteristic of innate immunity?
Which of the following is NOT a characteristic of innate immunity?
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What type of cells are primarily involved in the migration during inflammation?
What type of cells are primarily involved in the migration during inflammation?
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Which of the following best describes opsonization?
Which of the following best describes opsonization?
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Study Notes
Defensive Strategies - Immune System (Part 1)
- The immune system's evolution is linked to endosymbiosis.
- Eukaryotes, like animals, have a multi-celled immune system.
- Immune system is crucial for the survival of these organisms.
- The complexities of the system highlight its importance in survival and have real-world benefits, e.g., vaccines.
- The notes are based on Campbell 12th Edition, Chapter 47.
- It discusses animal defenses against infection.
- Specific concepts within the chapter are 47.1, 47.2, and 47.3.
General Introduction 1
- The immune system includes external defenses, innate immunity, adaptive immunity (acquired immunity), and the inflammatory response.
- The system comprises of cells and soluble factors (secreted by cells).
General Introduction 2
- The primary function of the immune system is to identify and destroy invading pathogens (e.g., viruses, bacteria, protists, worms).
- It aims to minimize the damage these invaders inflict.
Immune System Response
- An immune response involves recognizing invaders (A) and mounting a reaction to eliminate them (B).
- This involves recognizing the invader and a subsequent reaction against it, to eliminate it.
- These concepts were noted by Roitt et al., 1998.
Infectious Agents-1
- Infectious agents are mainly microbes like viruses and bacteria.
- Worms, fleas, lice, and ticks are other infectious agents that can cause harm to host organisms.
- Viruses, such as influenza, HIV, COVID-19, measles, and mumps, are examples of infectious agents capable of causing harm or even death to their host.
Infectious Agents-2
- Examples of bacterial pathogens include typhoid, cholera, MRSA, E. coli, bubonic plague, and Lyme disease.
- Protozoa, such as malaria, sleeping sickness, and red water fever, are also categorized as infectious agents.
- Worms like liver flukes, tapeworms, and roundworms are included as infectious agents as well.
Infectious Agents-3
- All viruses and many bacteria and protists/protozoa only replicate within host cells.
- Cells provide a safe haven for pathogens.
- The cell’s plasma membrane presents a barrier against soluble factors like antibodies.
- The immune system's crucial role is to identify and destroy infected cells to eradicate pathogens and minimize damage.
Infectious Agents-4
- Other types of bacteria, protozoa, and parasites reside outside of host cells in body fluids and tissues, hence, requiring a different immune response compared to intracellular pathogens.
- A different immune response is required to handle these agents.
Types of Pathogens
- The immune system defends against four categories of pathogens:
- Extracellular bacteria, parasites, and fungi.
- Intracellular bacteria, parasites.
- Intracellular viruses.
- Parasitic worms (extracellular).
Inflammatory Response-1
- Pathogens trigger inflammation.
- Inflammation is characterized by increased blood supply to the affected area.
- Increased permeability of capillaries allows larger molecules and cells to escape the blood vessels.
- White blood cells migrate from the capillaries to the infected tissues.
Innate Immunity-1
- Innate immunity is a natural or native immunity present before infection.
- The immune response is "poised" and ready to fight infection.
- It uses physical barriers, cells, and soluble factors to respond to infectious agents.
- This response is non-specific and does not have memory. This response remains non-specific regardless of whether the agent has been encountered before.
Innate Immunity-2 Cells
- The myeloid cell line includes phagocytes.
- Phagocytes are categorized as granulocytes.
- They include neutrophils, eosinophils, mast cells, and basophils.
- Monocytes (macrophages and dendritic cells): All three categories of these cells function as antigen-presenting cells (APCs).
Hematopoiesis
- Pluripotent hematopoietic stem cells differentiate into myeloid or lymphoid stem cells.
- Myeloid and lymphoid stem cells are crucial in the production of immune system cells that differentiate to combat infection.
Origin of Immune System Cells
- Cells develop in the thymus, bone marrow, and other secondary lymphoid tissues.
- Mature T-cells develop in the thymus gland.
- Mature B-cells develop in the bone marrow.
- Cells recirculate through blood.
Innate Immunity-Soluble Factors
- The innate immune system has soluble factors comprising proteins and peptides.
- Examples of these factors include complement proteins and interferons.
- Complement proteins play roles like lysis, chemotaxis, and opsonization.
- Interferons protect cells from viral invasion.
- Cytokines and chemokines are other proteins that participate in the response.
Opsonization
- Opsonins (e.g. antibodies, complement component C3b) bind to the surface of pathogens.
- This enhances phagocytosis by increasing effectiveness.
- Phagocytes have surface receptors to recognize opsonins and enhance the pathogen ingestion process.
Phagocytosis
- Phagocytosis is the process of engulfing and digesting microorganisms by certain immune cells.
- Phagocytes use pseudopodia to surround and engulf particles.
- The engulfed material (phagosome) merges with a lysosome for digestion.
Antigen-Presenting Cells (APCs)
- Dendritic cells (DCs) are a heterogeneous family of immune cells.
- They are crucial for bridging innate and adaptive immunity.
- They phagocytose pathogens and present antigens to T-cells.
- Antigens are presented in the form of MHC molecules.
T-cell Antigen Recognition
- T cells recognize antigens presented by MHC molecules on the surface of infected cells or APCs.
- This recognition triggers T-cell responses.
Adaptive Immune Response
- The adaptive immune response develops in reaction to infection; it is pathogen-specific and has memory.
- Adaptive immunity has increased potency with repeated exposure to a pathogen.
- The initial response is slower than the innate immune response.
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Description
Explore the complexities of the immune system in this quiz based on Campbell's 12th Edition, Chapter 47. We will delve into the evolution of the immune system, its external defenses, and the various forms of immunity. Test your understanding of how these mechanisms protect against infections and their relevance to survival.
