Immune System Overview Quiz
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Questions and Answers

What is the primary site of maturation for B lymphocytes?

Bone marrow

What two types of cells do activated B cells differentiate into?

Plasma B cells and Memory B cells

Which lymphoid organ is responsible for the maturation of T cells?

Thymus

Name one type of T cell and its function.

<p>Cytotoxic T cells; they destroy infected or cancerous cells.</p> Signup and view all the answers

What distinguishes memory B cells from plasma B cells?

<p>Memory B cells are long-lived and store immune memory, while plasma B cells are short-lived and secrete antibodies.</p> Signup and view all the answers

What is the role of the spleen in the immune system?

<p>The spleen filters blood and helps in the activation of lymphocytes.</p> Signup and view all the answers

What is the primary function of the 1st line of defense in the immune system?

<p>The primary function is to act as a physical barrier to block the entry of antigens.</p> Signup and view all the answers

List the four types of T cells mentioned.

<p>Cytotoxic T cells, Helper T cells, Memory cytotoxic T cells, Regulatory T cells.</p> Signup and view all the answers

How does the 2nd line of defense contribute to innate immunity?

<p>The 2nd line of defense contributes by utilizing nonspecific defenses like phagocytic cells and natural killer cells to block the spread of antigens.</p> Signup and view all the answers

Define adaptive immunity and its components.

<p>Adaptive immunity is a specific immune response characterized by the humoral response and cell-mediated response.</p> Signup and view all the answers

Define immunity in the context of B and T cells.

<p>Immunity is the ability of the immune system to recognize and eliminate pathogens via B and T cells.</p> Signup and view all the answers

What triggers the inflammatory response when the skin is cut?

<p>Damaged cells release chemical signals like histamine, which cause vasodilation and attract phagocytic WBCs.</p> Signup and view all the answers

What role do phagocytic WBCs play during the inflammatory response?

<p>Phagocytic WBCs ingest antigens through phagocytosis during the inflammatory response.</p> Signup and view all the answers

Describe a key feature of the 1st, 2nd, and 3rd lines of defense in the immune system.

<p>The 1st line provides physical barriers, the 2nd line features nonspecific defenses, and the 3rd line involves specific immune responses.</p> Signup and view all the answers

How do blood vessels change during the inflammatory response?

<p>Blood vessels dilate and become more permeable, allowing more blood flow and immune cells to reach the infected tissue.</p> Signup and view all the answers

What signals are released by damaged cells during an injury to initiate the immune response?

<p>Damaged cells release chemical signals like histamine and lymphokine.</p> Signup and view all the answers

What is immunity?

<p>Immunity is the body's ability to resist infections and diseases by recognizing and eliminating pathogens.</p> Signup and view all the answers

Describe the primary cell involved in the cell-mediated immune response.

<p>The primary cell involved is the T cell, specifically cytotoxic T lymphocytes, which destroy infected or cancerous cells.</p> Signup and view all the answers

What role do antibodies play in the humoral immune response?

<p>Antibodies bind to antigens on pathogens, neutralizing them and marking them for destruction by other immune cells.</p> Signup and view all the answers

What type of pathogens does the cell-mediated immune response primarily defend against?

<p>It primarily defends against intracellular pathogens, such as fungi, protozoa, and viruses.</p> Signup and view all the answers

Explain the concept of antigen-antibody interaction.

<p>Antigen-antibody interaction occurs when an antibody binds to a specific antigen, forming an antigen-antibody complex.</p> Signup and view all the answers

What is the primary function of plasma cells in the humoral immune response?

<p>Plasma cells produce antibodies that neutralize pathogens and assist in their elimination.</p> Signup and view all the answers

Which immune response is primarily responsible for defending against extracellular pathogens?

<p>The humoral immune response is primarily responsible for defending against extracellular pathogens.</p> Signup and view all the answers

What mechanism does the cell-mediated immune response use to destroy infected cells?

<p>The mechanism involves cytotoxic T cells binding to infected cells, leading to their lysis through apoptosis.</p> Signup and view all the answers

What is the primary role of cytotoxic T cells in adaptive immunity?

<p>Cytotoxic T cells release perforin and secrete granzyme to attack and destroy infected cells.</p> Signup and view all the answers

Describe the function of plasma cells in the immune response.

<p>Plasma cells secrete antibodies that target specific antigens in the body.</p> Signup and view all the answers

What distinguishes memory B cells from other B cells?

<p>Memory B cells initiate the production of plasma cells upon re-encountering the same bacteria or antigen.</p> Signup and view all the answers

How do interleukin-1 and interleukin-2 contribute to immune function?

<p>IL-1 activates helper T cells to secrete IL-2, while IL-2 stimulates the growth and differentiation of B and cytotoxic T cells.</p> Signup and view all the answers

What are MHC proteins and their importance in the immune response?

<p>MHC proteins, found on cells, present self-antigens to immune cells, helping to distinguish between self and non-self.</p> Signup and view all the answers

Differentiate between Class I and Class II MHC proteins.

<p>Class I MHC proteins are found on most nucleated cells, whereas Class II MHC proteins are present on cells involved in immune responses like macrophages and B cells.</p> Signup and view all the answers

What triggers the secondary immune response?

<p>The secondary immune response is triggered by memory B cells upon re-encountering the same antigen.</p> Signup and view all the answers

What is the significance of the cytokine interleukin-2 in adaptive immunity?

<p>Interleukin-2 is crucial for stimulating the proliferation and differentiation of B cells and cytotoxic T cells.</p> Signup and view all the answers

What is the main type of antibody produced in a primary immune response?

<p>IgM</p> Signup and view all the answers

How does the lag phase of the primary immune response compare to that of the secondary immune response?

<p>The lag phase in the primary response is longer, lasting 3 to 6 days, while it is much shorter in the secondary response, lasting 1 to 3 days.</p> Signup and view all the answers

What are the long-term effects on antibody levels in a secondary immune response?

<p>Antibody levels tend to remain high for a longer time.</p> Signup and view all the answers

Define a vaccine.

<p>A vaccine is a harmless derivative of a pathogen that stimulates the immune system to defend against the harmful pathogen.</p> Signup and view all the answers

List two sources of antigens used in vaccine production.

<p>Inactivated bacterial toxins and killed or weakened pathogens.</p> Signup and view all the answers

What is the significance of vaccination in the immune response?

<p>Vaccination is crucial as it stimulates the immune system to produce antibodies and build memory against future pathogen exposure.</p> Signup and view all the answers

What characterizes the response duration of a secondary immune response compared to a primary response?

<p>The secondary immune response is long-lasting, while the primary response is short-lived.</p> Signup and view all the answers

Why is the amount of antibody produced in a primary immune response usually lower than in a secondary immune response?

<p>The primary immune response generally produces antibodies in smaller amounts because it takes longer to recognize the pathogen and activate B cells.</p> Signup and view all the answers

What type of cells does HIV primarily attack to suppress the immune system?

<p>HIV primarily attacks helper T cells (T4 lymphocytes).</p> Signup and view all the answers

How does the immune system functionally change as HIV progresses toward AIDS?

<p>As HIV progresses, the immune system becomes extremely compromised, eventually leading to AIDS.</p> Signup and view all the answers

What components make up the structure of the HIV virus?

<p>HIV consists of 2 identical single-stranded RNA, 2 reverse transcriptase, a capsid, and an envelope glycoprotein.</p> Signup and view all the answers

What receptor does HIV bind to in order to infect helper T cells?

<p>HIV binds specifically to the CD4 accessory protein to infect helper T cells.</p> Signup and view all the answers

In addition to helper T cells, what other types of cells can HIV infect?

<p>HIV can also infect macrophages and brain cells that have low levels of CD4.</p> Signup and view all the answers

What is meant by immune suppression in the context of HIV infection?

<p>Immune suppression refers to a loss of immune function, where the immune system cannot defend against foreign or abnormal cells.</p> Signup and view all the answers

Can HIV survive outside of living cells, and what does that imply for social interactions?

<p>HIV does not survive outside living cells, implying that ordinary social contact poses no risk of infection.</p> Signup and view all the answers

What are the long-term implications of untreated HIV infection for an individual?

<p>Untreated HIV infection can lead to a severely compromised immune system and eventually develop into AIDS.</p> Signup and view all the answers

Flashcards

Immunity

The body's ability to resist infection and disease.

Innate Immunity

A type of immunity that is non-specific and present from birth. It provides a general defense against a wide range of pathogens.

Adaptive Immunity

A type of immunity that is specific to a particular pathogen. It develops after exposure to the pathogen and involves the immune system's ability to recognize and target specific antigens.

1st Line of Defense

The first line of defense against pathogens. It includes physical barriers like skin, mucous membranes, and secretions that prevent the entry of pathogens.

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2nd Line of Defense

The second line of defense against pathogens. It includes non-specific defenses like phagocytic cells, natural killer cells, and inflammatory responses that help to contain and eliminate pathogens that have entered the body.

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3rd Line of Defense

The third line of defense against pathogens. It involves specific defenses like humoral and cell-mediated immunity, which target specific pathogens and provide long-lasting protection.

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Inflammatory Response

A localized inflammatory response triggered by injury or infection. It involves a series of events that help to contain and eliminate pathogens.

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Phagocytosis

A process by which certain types of white blood cells engulf and destroy pathogens. It's a key component of both innate and adaptive immunity.

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Interleukin-1 (IL-1)

A type of cytokine that activates helper T cells (TH cells) to secrete IL-2.

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Interleukin-2 (IL-2)

A type of cytokine that stimulates the growth and differentiation of B cells and cytotoxic T cells.

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Major Histocompatibility Complex (MHC) Class I

Proteins found on the surface of most nucleated cells, responsible for presenting antigens to the immune system.

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Major Histocompatibility Complex (MHC) Class II

Proteins found on the surface of immune cells like macrophages, B cells, and dendritic cells, responsible for presenting antigens to helper T cells.

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Cell-Mediated Immune Response

An immune response that relies on T cells to directly destroy infected cells.

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Humoral Immune Response

An immune response that involves antibodies produced by B cells to neutralize pathogens.

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What is immunity?

The ability of an organism to resist disease caused by pathogens.

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What is a B cell?

A type of lymphocyte that matures in the bone marrow. They are responsible for producing antibodies, which are proteins that can bind to and neutralize pathogens.

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What is a T cell?

A type of lymphocyte that matures in the thymus. They help in recognizing and killing infected cells or cancer cells.

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What is a plasma B cell?

A type of B cell that lives for a short time and secretes antibodies to fight off infections.

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What is a memory B cell?

A type of B cell that lives for a long time and remembers previous encounters with pathogens. They are important for initiating a faster and stronger immune response during future infections.

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What is a cytotoxic T cell (TC)?

A type of T cell that directly kills infected cells or cancer cells.

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What is a helper T cell (TH)?

A type of T cell that helps to activate other immune cells, such as B cells and cytotoxic T cells.

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What is a regulatory/suppressor T cell?

A type of T cell that helps to regulate the immune response, preventing it from becoming too strong or attacking healthy cells.

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Cell-mediated immunity

The cell-mediated immune response involves T lymphocytes, particularly cytotoxic T cells (TC cells), which directly destroy infected cells or cancer cells.

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Humoral immunity

The humoral immune response involves B lymphocytes, which produce antibodies that bind to antigens, neutralizing or destroying pathogens.

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Antigen-antibody interaction

Antigen-antibody interactions occur when an antibody binds to its specific antigen, forming an antigen-antibody complex.

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Neutralization (Antigen-antibody interaction)

Neutralization occurs when an antibody binds to a pathogen and blocks its ability to infect a host cell.

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Opsonization (Antigen-antibody interaction)

Opsonization occurs when an antibody coats a pathogen, making it more easily recognized and destroyed by phagocytes.

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Complement activation (Antigen-antibody interaction)

Activation of the complement system occurs when an antibody binds to an antigen, triggering a cascade of events that leads to the destruction of the pathogen.

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Complement system

The complement system is a complex series of proteins that act as a protective mechanism against pathogens by directly killing cells, activating phagocytes, and recruiting other immune cells.

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How HIV Affects the Immune System

HIV attacks and destroys helper T cells, which are crucial for activating other immune cells. This weakens the immune system, making the body vulnerable to infections.

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HIV (Human Immunodeficiency Virus)

A virus that infects and weakens the immune system, leading to AIDS.

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AIDS (Acquired Immunodeficiency Syndrome)

The stage of HIV infection where the immune system is severely compromised, making the body susceptible to various opportunistic infections.

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Viral Integration

The process by which a virus's genetic material is incorporated into the host cell's DNA.

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gp120

The main protein on the surface of HIV that binds to CD4 receptors on the surface of helper T cells, allowing the virus to enter the cell.

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CD4

A protein on the surface of helper T cells that HIV binds to, allowing the virus to enter the cell.

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HIV Targets Other Cells

HIV can also infect macrophages and brain cells, which have lower levels of CD4.

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Primary Immune Response

The initial immune response upon encountering a pathogen for the first time. It's characterized by a slower response, primarily IgM antibody production, and a shorter duration.

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Secondary Immune Response

The immune response after a second or subsequent exposure to the same pathogen. It's faster, more robust, primarily IgG antibody production, and longer-lasting due to memory cells.

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Vaccine

A substance that stimulates the immune system to produce antibodies against a specific pathogen, without causing disease.

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Inactivated Bacterial Toxins (Vaccines)

Inactive toxins produced by bacteria. They are used in vaccines to stimulate immunity against the toxins without causing disease.

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Killed or Weakened Pathogens (Vaccines)

Pathogens that have been killed or weakened so they can't cause disease but still trigger an immune response.

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Genes Encoding Microbial Protein (Vaccines)

Pieces of genetic material from pathogens, usually DNA or RNA, that encode for specific proteins. These proteins can stimulate an immune response.

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Vaccination

The process of introducing a vaccine into the body to induce immunity against specific diseases.

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Study Notes

Chapter 11: Immunity

  • Immunity is the body's ability to recognize and protect itself from foreign substances that can cause disease.
  • Pathogens include viruses, bacteria, and soluble toxin proteins.

11.1 Immune Response

  • Immunity types include innate and adaptive.
  • Innate immunity represents non-specific defenses present at birth.
  • Adaptive immunity represents specific defenses acquired through exposure to pathogens.

11.1 (b) Types of Immunity

  • Immunity types include inherited/inborn, innate, and acquired.
  • Innate immunity is further divided into natural and artificial immunization.
  • Natural immunity includes active (contact with disease) and passive (placenta, mother's milk).
  • Artificial immunization includes active (vaccine) and passive (serum).

11.1 (b) Lines of Defense

  • The first line of defense includes physical barriers like skin and mucous membranes.
  • The second line of defense involves blocking pathogen spread using phagocytic cells, natural killer cells, and inflammation.
  • The third line of defense, the immune system, includes humoral and cell-mediated responses.

11.1 (b) First Line of Defense: Skin

  • Skin acts as a physical barrier against pathogens.
  • Chemicals and pathogens are kept on the opposite side of the skin surface.

11.1 (b) Second Line of Defense

  • Damaged cells release chemical signals (histamine, lymphokine).
  • Blood vessels dilate (vasodilation), becoming more permeable.
  • Blood clotting is stimulated.
  • Phagocytic white blood cells (WBCs) are attracted to the infected tissue.
  • Pathogens are ingested by phagocytosis.
  • Response includes heat, swelling, pain, and redness (inflammation).

11.2 Antibody

  • Antibodies, also known as immunoglobulins (Ig), are proteins produced by plasma cells.
  • Antibodies bind to specific antigens.

11.2 (a) Antibody Structure

  • Antibodies are Y-shaped proteins.
  • They consist of four polypeptide chains: two identical light chains and two identical heavy chains.
  • Each chain has a constant region (C) and a variable region (V).
  • Variable regions combine to make the antigen-binding site.
  • Disulfide bridges hold the chains together.

11.2 (a) Antibody Structure (Continued)

  • Amino acid sequences in the variable region vary significantly between antibodies.
  • The variable region of both heavy and light chains combines to form the antigen-binding site.
  • The antigen-binding site binds to specific antigens.

11.2 (b) Antibody Classes

  • Five classes of antibodies exist based on constant region differences on heavy chains: IgG, IgE, IgM, IgA, and IgD.
  • Each class has specific functions in immune responses.

11.3 Lymphocyte Development

  • Lymphocytes, including B cells and T cells, are produced in bone marrow.
  • B cells mature in bone marrow, while T cells mature in the thymus gland.

11.3 (a) Blood Cells

  • Blood cells include erythrocytes, leukocytes (granulocytes: neutrophils, eosinophils, basophils), and leukocytes (agranulocytes: monocytes and lymphocytes).
  • Lymphocytes include B cells and T cells.
  • Neutrophils, eosinophils and basophils are granulocytes.
  • Monocytes and lymphocytes are agranulocytes.
  • Lymphocytes make up the immune system.
  • Macrophages remove foreign material from the body.

11.3 (a) B Cells

  • B lymphocytes are produced and mature in bone marrow.
  • B lymphocytes differentiate into plasma cells and memory B cells.
  • Plasma cells secrete antibodies.
  • Memory B cells store memory of previous exposures to pathogens for faster responses during future infections.

11.3 (a) T Cells

  • T lymphocytes are produced in bone marrow but mature in the thymus gland.
  • Types of T cells include cytotoxic T cells (Tc), helper T cells (Th), memory cytotoxic T cells, regulatory/suppressor T cells (Ts).

11.3 (a) Types of T Cells (Continued)

  • Cytotoxic T cells recognize and kill infected cells by secreting perforin and granzymes.
  • Helper T cells secrete interleukin-2 to activate both B cells and cytotoxic T cells.
  • Regulatory T cells help end the immune response and prevent autoimmunity.
  • Memory T cells persist after an infection and produce a rapid response on subsequent exposure to the same antigen.

11.3 (b) Lymphoid Organs

Lymphocytes migrate to lymphoid organs for maturation and function

  • Thymus
  • Bone marrow
  • Lymph nodes
  • Spleen
  • Tonsils

11.4 Development of Adaptive Immunity

Adaptive immunity involves responses to specific antigens.

  • Cell-mediated immunity involves cytotoxic and helper T cells defending against intracellular pathogens and cancerous/infected cells.
  • Humoral immunity involves B cells that produce antibodies to defend against antigens.

11.4 (c) Antibody Interactions

  • Neutralization: Antibodies bind to pathogens preventing them from interacting with host cells.
  • Opsonization: Antibodies bind to pathogens to increase their uptake by phagocytes like macrophages or neutrophils.
  • Complement System Activation: Antibodies activate the complement system, leading to pore formation in pathogen membranes and pathogen lysis.

11.4 (d) Primary and Secondary Immune Responses

  • Primary response is the immune reaction to a pathogen for the first time.
  • Secondary response is the immune reaction upon subsequent exposure to the same pathogen.
  • Primary and secondary immune responses differ in time taken and effectiveness.
  • Primary response initially produces IgM, while secondary response is faster and primarily produces IgG antibodies, thereby neutralizing pathogens more effectively.

11.5 Immunization

  • A vaccine is a harmless derivative of a pathogen used to create an immune response.
  • Sources include inactivated bacterial toxins, killed or weakened pathogens, and genes encoding microbial proteins (DNA, RNA, and proteins).
  • Autoimmune diseases include Systemic Lupus Erythematosus (SLE), multiple sclerosis, and type I diabetes.
  • HIV infection causes immune suppression by attacking helper T cells, disrupting immune function and leading to AIDS.

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Topic 11 Immunity PDF

Description

Test your knowledge on the key components and functions of the immune system, including B and T cell maturation, types of immune responses, and the role of different lymphoid organs. This quiz covers concepts related to innate and adaptive immunity, as well as the body's first, second, and third lines of defense.

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