Immune System Overview

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Questions and Answers

Which type of antigen presenting cell (APC) is most efficient in initiating primary immune responses?

Helper T-cells

Dendritic cells (correct)

B-cells

Macrophages

What is the primary function of MHC molecules in antigen presentation?

To directly kill infected cells

To activate B-cells to produce antibodies

To display processed antigen fragments to T-cells (correct)

To engulf and digest pathogens

Which of the following is NOT a key feature of antigen presenting cells (APCs)?

They capture antigens from pathogens or damaged cells

They activate naïve T-cells to start a specific immune response

They present antigens to B-cells to activate antibody production (correct)

They process antigens into smaller fragments

Where are dendritic cells primarily found?

In tissues in contact with the external environment Signup and view all the answers

Which type of T-cell interacts with MHC Class I molecules on APCs?

Cytotoxic T-cells (CD8+) Signup and view all the answers

How do macrophages contribute to the immune response?

By presenting antigens to T-cells and phagocytosing pathogens Signup and view all the answers

What is the role of B-cells in antigen presentation?

To present antigens to helper T-cells for antibody production Signup and view all the answers

Which of the following is NOT a characteristic of adaptive immunity?

Fast response time Signup and view all the answers

What is an antigen primarily responsible for in the immune system?

Inducing the production of antibodies Signup and view all the answers

What characterizes innate immunity compared to adaptive immunity?

It is rapid and non-specific Signup and view all the answers

How do vaccines function within the immune system?

They stimulate the adaptive immune system's memory function Signup and view all the answers

What role do granulocytes play in the immune system?

Providing a rapid, non-specific defense against infections Signup and view all the answers

What differentiates 'self-antigens' from 'non-self antigens'?

Self-antigens are recognized as part of the body Signup and view all the answers

Which type of immune response is characterized by a slower reaction to pathogens?

Adaptive immune response Signup and view all the answers

What type of substances are often considered antigens?

Proteins, peptides, and polysaccharides Signup and view all the answers

What defines the granules found in granulocytes?

They contain enzymes and substances to combat pathogens Signup and view all the answers

What is the primary function of antigen presenting cells (APCs)?

Capture and display antigens to T-cells Signup and view all the answers

Which of the following describes the innate immune response?

Is the first line of defense against infections Signup and view all the answers

Which type of lymphocyte is responsible for humoral immunity?

B lymphocytes Signup and view all the answers

Which component is NOT part of the innate immune response?

Cytotoxic T-cells Signup and view all the answers

What role do cytotoxic T-cells play in the immune response?

They kill virus and tumor cells Signup and view all the answers

How do the innate and adaptive immune responses interact?

Innate responses can prime the adaptive response Signup and view all the answers

Which cell type is NOT classified as a lymphocyte?

Macrophages Signup and view all the answers

What is a characteristic feature of the adaptive immune system?

Production of antibodies and immunological memory Signup and view all the answers

Which of the following is a component of the innate immune response?

Physical barriers Signup and view all the answers

What is the primary role of cytokines in the immune response?

Activate phagocytes to kill ingested microbes Signup and view all the answers

Study Notes

Immune System Cells & Tissues

The immune system is triggered by antigens, which are toxins or foreign substances that induce an immune response.
Antigens, often proteins, peptides, or polysaccharides, can originate from within the body (self-antigen) or from the external environment (non-self).
Vaccines are antigens that can trigger the adaptive immune system to produce memory to a specific disease, inducing immunity to it.

Immune Response Branches

The immune response has two main branches: innate and adaptive.
The innate response is the first line of defense, providing an immediate, non-specific response to pathogens.
Adaptive immunity develops over time, providing long-lasting immunity with high specificity for certain antigens.

Innate Immunity

Components of innate immunity include physical barriers (skin, mucous membranes), chemical barriers (enzymes, stomach acid), and immune cells (natural killer cells, macrophages, neutrophils).
The innate response is non-specific, but responds to a broad range of pathogens.
The response is extremely fast—occurring within minutes or hours of exposure to pathogens.
Innate immunity has no immunological memory; the response is the same each time a pathogen is encountered.
The innate immune system relies on pattern recognition receptors (e.g., TLRs) that find pathogen-associated molecular patterns (PAMPs).

Adaptive Immunity

The adaptive immune response relies on B-cells (which produce antibodies) and T-cells (helper and cytotoxic) for defense against a specific pathogen.
The adaptive immune response is highly specific, targeting specific antigens.
The response typically takes several days or more to fully develop, with a key aspect being the development of immune memory for future encounters.
Adaptive immunity relies on receptors that can be somatically recombined from existing diversity to detect specific antigens.

Antigen-Presenting Cells (APCs)

APCs, like dendritic cells, macrophages, and B cells, capture antigens from pathogens or damaged cells, process them, and display them on their surface to T-cells.
APCs play a critical role in initiating the adaptive immune response by presenting antigens to T-cells.
Antigen presentation involves the uptake of antigens, their processing into smaller fragments, loading these fragments onto major histocompatibility complex (MHC) molecules, and displaying these MHC-antigen complexes on the cell surface.
This presentation triggers the activation of specific T-cells.

Lymphocytes

Lymphocytes (B and T cells) are key players in adaptive immunity.
B cells mediate humoral immunity, producing antibodies targeting pathogens.
T cells mediate cell-mediated immunity, targeting infected or cancerous cells.
Several types of T cells exist, with different functions (e.g., Cytotoxic T cells, Helper T cells).
Different classes of T cells and NK cells require specific activation cues to respond to infection.

Effector Cells

Effector cells (T cells, macrophages and granulocytes) eliminate antigens
They function by directly attacking and killing infected or abnormal cells
Several different types of granulocytes have different roles in immunity.

Immune System Tissues and Organs

Generative lymphoid organs (Bone Marrow and Thymus) are where immune cells are made and mature.
Secondary lymphoid organs (Lymph nodes and the Spleen) play a critical role in activating immune responses (specifically, adaptive).
Mucosal-associated lymphoid tissue (MALT) protects mucosal surfaces.
These tissues work together to facilitate the encounter and activation of immune cells.

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Description

This quiz covers essential concepts of the immune system, including the roles of different immune cells and tissues. Explore the mechanisms behind innate and adaptive immunity, and learn how antigens trigger immune responses. Perfect for biology students seeking to strengthen their understanding of immunology.