Immune System Study Guide

Questions and Answers

What is the purpose of the destruction of pathogens in lymph nodes?

To prevent pathogens from travelling throughout the body

To produce antibodies that enhance inflammation

To enable the activation of T cells and other immune cells (correct)

To activate memory B cells only

What is a result of T-cells that incorrectly recognize 'self'?

Decreased immune response effectiveness

Autoimmune disease (correct)

Formation of memory B cells

Enhanced antibody production

Which option best describes the sequence of phases in the immune response?

Termination, Memory, Recognition, Amplification, Effector

Recognition, Amplification, Effector, Termination, Memory (correct)

Recognition, Memory, Amplification, Termination, Effector

Effector, Recognition, Amplification, Termination, Memory

What defines primary immunodeficiency?

Congenital deficits in T-cells, B-cells, or lymphoid tissue Signup and view all the answers

Which of the following is NOT a source of iatrogenic immunodeficiency?

Natural aging processes Signup and view all the answers

What is the primary function of innate immunity?

To eliminate pathogens rapidly and non-specifically Signup and view all the answers

What differentiates an immunogen from an antigen?

Immunogens provoke an immune response, antigens do not Signup and view all the answers

Which component of innate immunity is not classified as a cellular component?

Epithelial barriers Signup and view all the answers

What role do chemokines play in the immune response?

They induce migration of leukocytes to enhance inflammation Signup and view all the answers

Which statement about adaptive immunity is accurate?

It continuously develops throughout a person's lifetime Signup and view all the answers

What is the role of acute phase proteins in the immune system?

To promote pro-inflammatory effects and alter metabolism Signup and view all the answers

Which of the following best describes the relationship between innate and adaptive immunity?

Innate immunity mediates the initiation and development of adaptive immunity Signup and view all the answers

Interferons are primarily produced by which type of cells?

Cells that are infected with viruses Signup and view all the answers

What distinguishes active immunity from passive immunity?

Active immunity results from exposure to antigens, whereas passive immunity involves transfer of antibodies. Signup and view all the answers

Which immunoglobulin class is primarily involved in allergic reactions?

IgE Signup and view all the answers

What role does IgA play in the immune system?

It is predominant on mucus membranes and prevents pathogen adherence. Signup and view all the answers

What is the initial step in the process of cell-mediated immunity?

Macrophages and dendritic cells phagocytose antigens. Signup and view all the answers

Which statement about the structure of antibodies is true?

Antibodies consist of variable regions that allow antigen specificity. Signup and view all the answers

What is the relationship between IgG and immunity?

IgG offers long-lasting immunity and can be passed through the placenta. Signup and view all the answers

Which mechanism is primarily responsible for the rejection of tissue transplants?

Cell-mediated immunity involving T-cells. Signup and view all the answers

Which immunoglobulin class is the first to respond during an immune reaction?

IgM Signup and view all the answers

Study Notes

Immune System Overview

Innate immunity provides rapid, non-specific defense against pathogens and initiates adaptive immunity.
Adaptive immunity is pathogen-specific, develops memory, and provides long-lasting protection.

Key Components of Innate Immunity

Exterior Defenses: Include epithelial barriers, mucosa, and secretions.
Cellular Components: Comprised of leukocytes such as natural killer cells, neutrophils, monocytes/macrophages, eosinophils, basophils, mast cells, and platelets.
Soluble Mediators:
- Complement: A protein system that induces acute inflammatory responses and damages microbial membranes.
- Cytokines: Proteins that modify cellular behavior, influencing immune responses.

Types of Cytokines

Chemokines: Small cytokines that enhance inflammation and attract leukocytes by changing blood flow and increasing vascular permeability.
Interferons: Produced by virus-infected cells to boost resistance against viral replication.
Acute Phase Proteins: Pro-inflammatory cytokines that alter metabolism, blood flow, and produce other proteins.

Components of Adaptive Immunity

Humoral Immunity: Involves B cells and antibody production.
Cell-mediated Immunity: Involves T cells and direct cell interactions for pathogen elimination.

Antigens vs. Immunogens

Antigen: Any molecule that binds to an antibody or T-cell receptor.
Immunogen: A specific type of antigen that triggers an immune response, often enhanced by substances like adjuvants.

Active vs. Passive Immunity

Active Immunity: Long-lasting protection from exposure to antigens. Can be natural (e.g., virus exposure) or artificial (e.g., vaccination).
Passive Immunity: Temporary immunity obtained by transferring antibodies from an immune individual to a non-immune individual, either naturally (e.g., transplacental) or artificially (e.g., antibody inoculation).

Structure and Function of Antibodies

Produced by B lymphocytes, antibodies have an antigen-binding site for specificity and constant regions important for immune function.

Major Immunoglobulin (Ig) Classes

IgM: First responder antibody; activates complement.
IgG: Major antibody in the blood; provides lasting immunity and crosses the placenta.
IgA: Predominant in mucosal areas and bodily secretions; prevents pathogen adherence.
IgE: Associated with allergies and defense against parasites; found on mast cells and basophils.
IgD: Acts as an antigen receptor on mature B cells.

Clinical Relevance of Cell-mediated Immunity

Protects against intracellular pathogens and is involved in tissue transplant rejection and some autoimmune diseases.

Process of Cell-mediated Immunity

Macrophages and dendritic cells present antigens to T-cells after capturing them.
Activated T-cells undergo clonal expansion, optimizing pathogen destruction and initiating additional immune responses through B-cell activation.

Formation of T-lymphocytes

T-cells originate in the bone marrow, mature in the thymus, and develop T-cell receptors while eliminating self-reactive cells to prevent autoimmune diseases.

Formation and Maturation of B-lymphocytes

Matured cells express IgM and IgD in the bone marrow and produce specific antibodies upon activation. They can develop into plasma cells or memory B cells for secondary responses.

Phases of the Immune Response

The immune response consists of five phases: recognition, amplification, effector, termination, and memory.

Immunodeficiency Types

Primary Immunodeficiency: Congenital issues in T-cells, B-cells, or lymphoid tissue.
Secondary Immunodeficiency: Results from diseases that depress immune function.

Iatrogenic Sources of Immunodeficiency

Include treatment with cytotoxic drugs, corticosteroids, immunosuppressive drugs, radiation therapy, and surgical splenectomy.

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Description

This study guide explores the key functions of the immune system, focusing on the differences between innate and adaptive immunity. It highlights how innate immunity provides rapid, non-specific responses while adaptive immunity targets specific pathogens and develops immunological memory. Understanding these concepts is crucial for a deeper knowledge of human health and disease.