Immunology Overview Quiz

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Questions and Answers

What is the primary focus of the specific immune response?

Natural resistance to most pathogens

Recognition and defense against distinct invaders (correct)

Immediate response to any pathogen

Physical barriers such as skin and mucous membranes

Which of the following mechanisms is NOT part of the innate defense system?

Phagocytosis

Inflammation

Microbial antagonism

Memory functions (correct)

What role do lymphocytes play in the immune system?

They carry out phagocytosis of invaders

They form physical barriers against pathogens

They are responsible for the specific immune response (correct)

They produce signaling molecules like cytokines

How do specific defenses develop over time?

By 'teaching' immune cells to differentiate between foreign and self Signup and view all the answers

Which statement correctly describes the second line of defense in immune response?

It involves phagocytosis and inflammation Signup and view all the answers

What is an epitope?

A specific region of a molecule with antigenic properties Signup and view all the answers

Which of the following components is NOT part of the lymphatic system?

Erythrocytes Signup and view all the answers

How can antigens enter the body?

Via organ transplants or skin grafts Signup and view all the answers

Which type of immune response is primarily associated with B cells?

Humoral immune response Signup and view all the answers

What type of T cell is primarily responsible for directing the specific immune response?

T helper cells (CD4) Signup and view all the answers

What triggers apoptosis in infected or cancerous cells?

T cytotoxic cells (CD8) Signup and view all the answers

Where do T cells mature in the human body?

Thymus Signup and view all the answers

What is the primary role of memory T cells?

To provide long-term immunity Signup and view all the answers

Which of the following is a common intracellular pathogen recognized by T cells?

Viruses Signup and view all the answers

What is required for T cells to respond to an antigen?

Establishment of safeguard signals with an antigen-presenting cell Signup and view all the answers

What is the primary action of perforin in the immune response?

To penetrate and destroy targeted cells Signup and view all the answers

What mechanism prevents T cells from attacking the body's own tissues?

Safeguard signals through antigen recognition Signup and view all the answers

What is the primary function of lymphatic vessels?

To transport lymph from tissues to lymph nodes Signup and view all the answers

Where do B-cells mature and arise from?

Red bone marrow Signup and view all the answers

What role do lymph nodes primarily serve in the lymphatic system?

Housing leukocytes to attack foreign antigens Signup and view all the answers

Which organ filters bacteria, viruses, and toxins from the blood?

Spleen Signup and view all the answers

What is the significance of memory cells in the lymphatic system?

They facilitate immediate responses to the same antigen in future encounters. Signup and view all the answers

Which of the following tissues is not part of the mucosa-associated lymphoid tissues (MALT)?

Bone marrow Signup and view all the answers

Clonal deletion is important for which aspect of lymphocyte maturation?

Eliminating self-reactive B and T-cells Signup and view all the answers

What type of fluid is lymph most similar to?

Blood plasma Signup and view all the answers

What process eliminates self-reactive lymphocytes in the immune system?

Clonal Deletion Signup and view all the answers

Where do B cells originate from?

Bone Marrow Signup and view all the answers

What types of cells do activated B cells differentiate into?

Plasma cells and memory cells Signup and view all the answers

What is the main function of antibodies in the immune response?

To bind to antigens Signup and view all the answers

How many antigen-binding sites does each antibody molecule have?

Two Signup and view all the answers

Which class of antibody is primarily involved in mucosal immunity?

IgA Signup and view all the answers

What type of bonds hold the polypeptide chains of antibodies together?

Covalent bonds Signup and view all the answers

Which of the following is NOT a class of antibodies?

IgP Signup and view all the answers

What determines the class of antibody involved in an immune response?

The type of foreign antigen Signup and view all the answers

What is the role of memory B cells?

To ensure a faster response upon re-exposure to the same antigen Signup and view all the answers

Which function is NOT associated with the activation of complement in the immune response?

Secretion of cytokines Signup and view all the answers

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

Producing only antibodies complementary to specific antigens Signup and view all the answers

What characterizes memory B cells compared to plasma B cells?

They remain in lymphoid tissue and can respond to the same antigen later Signup and view all the answers

Which statement is accurate regarding antigen binding to B cells?

Antigens are typically presented by Antigen Presenting Cells (APC) Signup and view all the answers

What are the main components involved in the humoral immune response?

B cell activation and clonal selection Signup and view all the answers

What causes the activation of B cells during the immune response?

Chemical signals from T helper cells Signup and view all the answers

How do memory B cells respond to recurring infections?

They rapidly divide to form new clones of the same specific B cells Signup and view all the answers

What role do T helper cells play in the humoral immune response?

They provide signals that stimulate B cell activation Signup and view all the answers

Study Notes

Defense Mechanisms Overview

Innate defenses provide natural resistance to pathogens.
Nonspecific defenses include the first line (skin, mucous membranes, microbial antagonism) and second line (phagocytosis, inflammation, fever, signaling molecules).
Specific defenses involve lymphocytes and antibodies (specific immune response).

Third Line of Defense

Specific immunity allows the body to recognize and defend against specific invaders and their products.
This is a "smart" system with memory for faster responses to later exposures.
It's developed over time as immune cells learn to differentiate between foreign and self-substances.

Antigens

Antigens are molecules or fragments triggering a specific immune response.
They include components of bacterial cell walls, capsules, pili, flagella, viral proteins, fungal and protozoan proteins.
Epitopes are specific regions of a large molecule with antigenic properties.
Antigens enter the body through various routes like breaks in skin and mucous membranes, injections, or organ transplants.

Lymphatic System

A network of organs, vessels, and cells that screens body tissues for foreign antigens.
Lymphatic vessels collect lymph (liquid similar to blood plasma) from tissues.
Lymph nodes, spleen, tonsils, and mucosa-associated lymphoid tissues (MALT) are key components.

Lymphatic System Components

Lymphoid cells (lymphocytes, including T-cells and B-cells) are important components.
These cells develop from stem cells in the red bone marrow.
Lymph nodes house leukocytes combatting foreign antigens using lymph.
Lymph nodes are concentrated in key areas of the body.

Lymphocytes (Overview)

Lymphocytes (T cells and B cells) originate from red bone marrow or thymus.
Primarily found in spleen and lymph nodes, with some circulating in blood.
Stimulation by a specific antigen triggers cell division to create memory cells and active cells .

Lymphocyte Editing by Clonal Deletion

This crucial process ensures the immune system doesn't attack the body's own cells.
Immune cells (B cells and T cells) are edited to eliminate self-reactive cells.

Characteristics of B-cells

B cells originate from stem cells in bone marrow.
B cells that react to self-antigens are typically inactivated (clonal deletion).
Each cell displays two matching receptors, crucial for antigen specificity.
Activated B cells differentiate into plasma cells that produce antibodies.
Memory cells await restimulation by the same antigen.

Antibodies (Immunoglobulins)

Antibodies are soluble proteins that circulate in blood and lymph.
They are secreted by plasma cells (activated B cells) and are part of the humoral immune response.
Each antibody has two antigen-binding sites.

Structure of Antibodies

Antibodies are composed of four polypeptides (two heavy chains and two light chains) with a characteristic Y shape.
Each antibody has antigen-binding sites and a constant region.

Classes of Antibodies

Antibodies are classified into five main types: IgA, IgD, IgE, IgG, and IgM.
Each class has specific functions and roles in the immune response.

Antibody Function

Antibodies bind to specific antigens through complementary antigen-binding sites.
This binding triggers various immune responses, including complement activation and inflammation.

Humoral Immune Response

This response is mounted against exogenous pathogens.
Pathogens are targeted by antibodies in bodily fluids (e.g., blood, lymph).
Components include antigen-specific B cell activation, clonal expansion, and plasma cell formation.

Cell-Mediated Immunity

T cells (T helper cells/cytotoxic T cells) are key components in this response targeting intracellular pathogens.
T helper cells help other cells of the immune system; cytotoxic T cells directly attack infected or cancerous cells.

Type T Lymphocytes (T cells)

T cells develop in red bone marrow and mature in the thymus.
They must recognize MHC ("Major Histocompatibility Complex") molecules to correctly target pathogens.
T cells circulate in lymph and blood, migrating to key lymphoid areas.

Cell-Mediated Immune Response

The response targets intracellular pathogens.
These include viruses, and abnormal body cells (cancer).
Activation involves displaying pathogens on the cell membrane, activating T helper cells, and triggering a T cell response.
Memory cells are also created in this response

Regulation of Cell-Mediated Response

Careful regulation is needed to avoid attacking the body's own cells (autoimmune responses).
T cells require specific stimulation by antigen-presenting cells to activate and respond efficiently.

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Description

Test your knowledge on the immune system, including innate and specific defenses, the role of lymphocytes, and the nature of antigens. This quiz covers the fundamental concepts behind the body's defenses against pathogens and the mechanisms involved in immune memory.