Immunology Chapter 2: Immune System Cells and Organs
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Questions and Answers

What is the primary role of primary lymphoid organs?

  • To facilitate lymphocyte development and maturation (correct)
  • To provide nutrients to immune cells
  • To store leukocytes
  • To filter pathogens from the bloodstream

Which of the following describes true pathogens?

  • Pathogens that only cause disease in compromised hosts
  • Organisms capable of causing disease in healthy individuals (correct)
  • Microorganisms that do not trigger an immune response
  • Pathogens that cannot survive outside a laboratory

What is the primary function of the thymus in lymphocyte development?

  • Site for B-cell maturation
  • Filtering pathogens from lymph
  • Production of red blood cells
  • Maturation of T lymphocytes (correct)

What does virulence refer to regarding pathogens?

<p>The intensity of the disease produced by pathogens (B)</p> Signup and view all the answers

Which primary lymphoid organ is responsible for the maturation of T lymphocytes?

<p>Thymus (C)</p> Signup and view all the answers

Which of the following statements regarding bone marrow is true?

<p>It produces various blood cells including plasma cells. (D)</p> Signup and view all the answers

What is the primary function of macrophages in the immune system?

<p>Engulf and destroy pathogens (D)</p> Signup and view all the answers

What occurs in secondary lymphoid organs (SLO)?

<p>Recognition and activation of lymphocytes by antigens (D)</p> Signup and view all the answers

Where is the spleen located?

<p>Left abdominal area (B)</p> Signup and view all the answers

What term refers to the ability of a pathogen to induce an immune response?

<p>Immunogenicity (A)</p> Signup and view all the answers

Which of the following statements about opportunistic pathogens is true?

<p>They cause disease when they inhabit atypical body locations. (A)</p> Signup and view all the answers

What does the presence of swollen and painful lymph nodes usually indicate?

<p>A reaction to an immune response (B)</p> Signup and view all the answers

What is hematopoiesis?

<p>The production of blood cells during fetal development (B)</p> Signup and view all the answers

Which of the following is NOT a primary lymphoid organ?

<p>Spleen (D)</p> Signup and view all the answers

What type of lymphocyte maturation occurs primarily in the bone marrow?

<p>B-cell maturation (A)</p> Signup and view all the answers

What role does the lymph node play in the immune response?

<p>It filters foreign pathogens and activates lymphocytes. (D)</p> Signup and view all the answers

What is one of the primary functions of the spleen?

<p>Production of immune cells to fight pathogens (B)</p> Signup and view all the answers

Which type of cells represents the majority in lymph and lymph nodes?

<p>Lymphocytes (B)</p> Signup and view all the answers

What role do tertiary lymphoid tissues play during an inflammatory response?

<p>They import lymphoid cells (B)</p> Signup and view all the answers

What is the characteristic shape of a monocyte's nucleus?

<p>Single lobed and kidney-shaped (D)</p> Signup and view all the answers

During fetal life, what function does the spleen serve?

<p>Production of blood cells (A)</p> Signup and view all the answers

What is the lifespan of circulating monocytes in the blood before they migrate to tissues?

<p>8 hours (D)</p> Signup and view all the answers

What are the main subpopulations of lymphocytes?

<p>T lymphocytes, B lymphocytes, natural killer cells (D)</p> Signup and view all the answers

Which cells differentiate from promonocytes after entering the bloodstream?

<p>Mature monocytes (A)</p> Signup and view all the answers

What is the function of enzymes in the innate immune system?

<p>They mark germs for detection and attract immune cells. (D)</p> Signup and view all the answers

Which statement correctly describes the adaptive immune system?

<p>It targets specific pathogens more accurately after initial exposure. (B)</p> Signup and view all the answers

What types of cells are involved in the adaptive immune response?

<p>T lymphocytes and B lymphocytes. (C)</p> Signup and view all the answers

What is the primary role of T helper cells in the adaptive immune system?

<p>To activate other immune system cells. (A)</p> Signup and view all the answers

How do memory T cells improve the adaptive immune response?

<p>They help the immune system remember specific pathogens. (A)</p> Signup and view all the answers

Natural killer cells are primarily responsible for which of the following?

<p>Identifying and destroying infected or tumorous cells. (D)</p> Signup and view all the answers

What is the main consequence of the immune response involving both germs and immune cells?

<p>Formation of pus due to decaying cells. (C)</p> Signup and view all the answers

What feature do T cells possess that allows them to identify pathogens?

<p>They have surfaces with unique detection features. (D)</p> Signup and view all the answers

What initiates the multiplication of T cells?

<p>Attachment of a pathogen to a matching T cell (D)</p> Signup and view all the answers

What is the primary role of B cells once activated?

<p>To produce antibodies (D)</p> Signup and view all the answers

Which cells are responsible for recognizing self and non-self entities in the immune system?

<p>Lymphocytes (C)</p> Signup and view all the answers

What do secondary lymphoid organs primarily provide?

<p>Sites for lymphocyte activation (C)</p> Signup and view all the answers

What is a beneficial effect of the immune system?

<p>Protection from invaders (C)</p> Signup and view all the answers

Which type of cells have greater killing power but a shorter lifespan compared to macrophages?

<p>Polymorphonuclear neutrophilic leukocytes (C)</p> Signup and view all the answers

What transformation occurs to some activated B cells after their role in an immune response?

<p>They become memory cells (D)</p> Signup and view all the answers

What type of pathogens do the immune system primarily protect against?

<p>Both intracellular and extracellular pathogens (C)</p> Signup and view all the answers

What is a primary immunological function of macrophages?

<p>Phagocytosis (C)</p> Signup and view all the answers

Which change occurs during the differentiation of monocytes into macrophages?

<p>Increase in phagocytic ability (C)</p> Signup and view all the answers

What defines the role of eosinophils in the immune response?

<p>They kill large parasites through hydrolytic enzymes (B)</p> Signup and view all the answers

Which type of cell is involved in antigen presentation during the primary immune response?

<p>Dendritic cells (D)</p> Signup and view all the answers

What characterizes the nucleus of neutrophils?

<p>Multilobed (B)</p> Signup and view all the answers

Which function is NOT associated with basophils?

<p>Phagocytosis (B)</p> Signup and view all the answers

Which of the following accurately describes granulocytic cells?

<p>Include neutrophils, eosinophils, and basophils (C)</p> Signup and view all the answers

How do monocytes contribute to the adaptive immune response?

<p>By presenting antigens to T cells (D)</p> Signup and view all the answers

Flashcards

Primary Lymphoid Organs

The sites where lymphocytes develop and mature.

Lymphocytes

Immune cells that play key roles in the body's defense against pathogens.

Thymus

An organ where T cells mature.

Bone Marrow

Where both B and some T cells originate.

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Lymphoid Tissue

Tissue containing lymphocytes and other cells of the immune system.

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Macrophages

Cells that engulf and destroy pathogens.

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Natural Killer Cells

Immune cells that kill infected or cancerous cells.

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Pathogens

Microorganisms that can cause disease.

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Lymphocyte Development

Lymphocytes originate from lymphoid stem cells, multiply, and mature into immuno-competent cells.

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Primary Lymphoid Organs (PLO)

The bone marrow and thymus are responsible for lymphocyte maturation.

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Thymus Function

The thymus is an organ in the upper chest that helps T lymphocytes mature.

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Bone Marrow Function

The bone marrow produces red blood cells, plasma cells, various white blood cells, and other immune cells.

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Secondary Lymphoid Organs (SLO)

Organs such as lymph nodes and spleen sustain and initiate immune responses.

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Lymph Node Function

Lymph nodes filter and kill foreign pathogens in the lymphatic system.

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Spleen Function

The spleen is an SLO found in the left abdomen that helps fight infection.

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Lymphocyte Activation

Mature lymphocytes are activated when they encounter specific antigens in SLOs, multiplying and differentiating to combat the invaders.

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Spleen's primary function

Filtering blood, capturing antigens, and reacting to infections by producing immune cells, removing particulate matter and aged blood cells, and producing blood cells during fetal development.

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Immune cells production

The spleen creates immune cells (like antibodies) that fight pathogens or their antigens.

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Phagocytic cells

Cells like monocytes and macrophages that consume and eliminate harmful substances and dead cells.

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Monocytes

A type of white blood cell (leukocyte) that differentiates into macrophages in tissues.

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Tertiary Lymphoid Tissues

Areas with fewer immune cells than other lymphoid organs, that can import immune cells during inflammation.

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Lymphatic system

A network of vessels that collect fluid escaped from capillaries and return it to blood.

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Antibodies in spleen

The spleen produces antibodies in its white pulp. These antibodies eliminate pathogens and antibody-coated blood cells via lymph nodes and blood.

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Monocyte function

Monocytes help process and present antigens, and release cytokines.

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Macrophage development

Monocytes transform into macrophages in tissues, increasing in size, granule count, and phagocytic ability to fight pathogens.

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Macrophage immune function

Macrophages engulf pathogens (phagocytosis), present antigens to T cells, regulate inflammation, and produce immune factors.

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Neutrophil function

Neutrophils are the first responders in inflammation and are highly phagocytic.

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Eosinophil function

Eosinophils target large parasites and participate in allergic responses.

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Basophil function

Basophils release substances involved in allergic reactions.

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Dendritic cell function

Dendritic cells are antigen-presenting cells, crucial in initiating immune responses.

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Innate/Adaptive Immune System

The immune system is composed of innate (general responses) and adaptive (specific responses) components that defend the body from infection.

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What does pus indicate?

Pus forms during an immune response when both germs and immune system cells die and decay.

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What do enzymes do in the innate immune response?

Enzymes in the innate immune system mark germs for destruction, attract other immune cells, kill bacteria, and fight viruses.

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What are natural killer cells?

Natural killer cells are immune cells that specialize in identifying and destroying virus-infected or cancerous cells.

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When does the adaptive immune system take over?

The adaptive immune system takes over when the innate immune system fails to destroy pathogens.

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Adaptive Immune System: Speed vs. Accuracy

The adaptive immune system is slower than the innate system, but it is more accurate and can remember pathogens.

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What are T helper cells?

T helper cells are a type of T lymphocyte that activates other immune cells to start the adaptive immune response.

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What are cytotoxic T cells?

Cytotoxic T cells are T lymphocytes that kill infected or cancerous cells.

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What are memory T cells?

Memory T cells are T helper cells that remember a pathogen after an infection is defeated, allowing for a faster immune response next time.

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T cell activation

When a T cell encounters its matching pathogen, it starts to multiply, creating more specialized T cells to fight that specific pathogen.

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B cell activation

B cells are activated by T helper cells that recognize the same pathogen. This prompts B cells to multiply and transform into plasma cells.

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Plasma cell role

Plasma cells produce and release large amounts of antibodies into the bloodstream to target specific pathogens.

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Antibody specificity

Only B cells that match the invading pathogen are activated, ensuring that only the precise antibodies needed are produced.

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Memory B cells

Some activated B cells become memory B cells, forming part of the adaptive immune system's memory to quickly recognize and fight the same pathogen in the future.

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Immune system benefits

The immune system protects us from invaders like pathogens and eliminates altered or damaged cells within the body.

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Immune system downsides

The immune system can sometimes cause discomfort and collateral damage during inflammation or accidentally attack the body's own cells (autoimmunity).

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Polymorphonuclear neutrophils (PMNs)

Short-lived white blood cells with strong killing power, important for fighting off infections.

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Study Notes

Chapter Two: Organs and Cells of Immune System

  • The immune system is composed of various organs and tissues throughout the body
  • Learning Objectives: describe cells and organs of the immune system, lymphoid tissue, cells produced and key roles, morphology, source, and roles of macrophages, natural killer cells, cytotoxic, helper, suppressor, B lymphocytes and plasma cells.
  • Discuss the role of surface markers in cells involved with immunity, differentiating between T and B lymphocytes
  • Outline: Organs of the immune system and Cells of the immune system

Organs of the Immune System

  • The immune system responds to infections through coordinated activities of innate and adaptive immune components. This approach detects, contains, kills, or expels infectious agents
  • Tertiary lymphoid tissues contain fewer lymphoid cells than secondary lymphoid organs, and can import lymphoid cells during inflammatory responses. Cutaneous-associated lymphoid tissues (CALT) are a prominent example
  • Primary lymphoid organs (PLO): provide appropriate microenvironments for lymphocyte development and maturation. Examples include thymus, bone marrow, and fetal liver
  • Secondary lymphoid organs (SLO): maintain and initiate adaptive immune responses. Examples include spleen and lymph nodes

Cells of the Immune System

  • Lymphocytes: small, round cells found in peripheral blood, lymph nodes, lymphoid organs, and tissues. Represent 20-45% of total cells in peripheral blood and 99% of cells in lymph nodes
    • Lymphocytes are divided into T cells, B cells, and natural killer cells.
  • Phagocytic cells: monocytes and macrophages - mononuclear phagocytic cells
    • Granulocyte-monocyte progenitor cells differentiate into promonocytes and neutrophils
    • Promonocytes leave the bone marrow, enter the bloodstream, and mature into monocytes. Monocytes circulate in the blood for approximately 8 hours before entering tissues and differentiating into macrophages and dendritic cells.
    • Monocytes are single-lobed with kidney-shaped nuclei, measuring 12-15µm in size.
    • Macrophages: monocytes that migrate to tissues and differentiate
    • Differentiation involves cell enlargement 5-10 fold, increased intracellular granules, increased phagocytic ability, and production of higher levels of hydrolytic enzymes and cytokines
    • Macrophages have immunological functions like phagocytosis, antigen presentation to T cells, secretion of granulocyte-monocyte colony stimulating factors, secretion of lymphokines to activate inflammatory responses
  • Granulocytic cells:
    • Include neutrophils, eosinophils, and basophils
    • Neutrophils: 11-14µm in diameter, multilobed nuclei, prominent granules; constitute 50-70% of circulating leukocytes; phagocytic role in acute inflammatory response
    • Eosinophils: 11-15µm, heavily granulated, bilobed nucleus; contain hydrolytic enzymes that kill parasites too large to be phagocytized by neutrophils; involved in allergic inflammation
    • Basophils: non-phagocytic cells with prominent basophilic granules containing histamine, heparin, serotonin, and hydrolytic enzymes; function in providing anaphylactic allergic reactions
  • Dendritic cells: have long cytoplasmic extensions resembling nerve cell dendrites, highly pleomorphic, small central bodies, and needle-like processes. Function as antigen-presenting cells in primary immune response and have little role in phagocytosis

Innate and Adaptive Immune Response

  • The immune system reduces harmful impacts of infectious agents through coordinated activities of innate and adaptive immune components
  • Innate responses detect, target, contain, kill, or expel infectious agents
  • Immune resistance helps minimize the amount of dysfunction imposed by infection on host tissues

Innate Immune System

  • Innate is the body's first line of defense to invading germs. It responds to germs quickly in the same way to all pathogens.
    • Protection offered by skin and mucous membranes.
    • Protecting outer/inner body surfaces as a physical barrier to germs.
    • Chemical barriers like acid, enzymes, or mucus inhibit germs from foothold
    • Germ movements stopped through hair-like structures or body fluids like sweat or tears
    • Immune cells move to the pathogens. This causes the pathogen site to swell; heat up; and redden
    • Blood vessels expand which brings immune cells to the infection; phagocytic cells; natural killer cells
    • Phagocytic cells engulf and digest germs. Adaptive immune system recognizes these digested remains.
    • Immune system cells and proteins release substances to cause the death of both germs and immune cells. This forms pus.

Adaptive Immune System

  • The adaptive immune system takes over if the innate immune system fails to destroy pathogens. It targets specific pathogens.
    • It is slower than innate immunity.
    • Can remember pathogens (meaning the response is faster upon a subsequent infection by the same germ)
    • T lymphocytes
    • B lymphocytes
    • Antibodies (found in the blood and body fluids)

Summary of Immune System Cells and Organs

  • Lymphocytes are the key cells for the immune system, displaying specificity, diversity, memory, and self/non-self recognition.
  • Primary lymphoid organs are sites where lymphocytes mature and become antigenically committed
  • Secondary lymphoid organs capture antigens and provide sites for lymphocyte activation by interaction with antigens.

Function of the Immune System

  • Protection from pathogens (intracellular—viruses, some bacteria, parasites and extracellular—most bacteria, fungi, parasites)
  • Elimination of altered self.

Effects of Immune System

  • Beneficial: protection from invaders and elimination of altered self
  • Detrimental: discomfort and collateral damage, and damage to self

Immune Cell Development

  • Diagrams depicting various stages of development from stem cells to mature immune cells, along with the different types of white blood cells (leukocytes) This information is for study purposes only and does not substitute medical advice from a qualified medical practitioner.

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Chapter 2 Organs and Cells of Immune System PDF

Description

Explore the intricate world of the immune system in Chapter Two, focusing on the various organs and cells that play vital roles in immunity. This quiz will assess your understanding of lymphoid tissue, macrophages, lymphocytes, and the functions they perform. Delve into the differentiation of T and B lymphocytes and the significance of surface markers in immune responses.

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