Immune System 3rd Line of Defense Flashcards

Questions and Answers

What does the 3rd Line of Defense refer to?

Non-specific immunity

Natural immunity

Passive immunity

Specific immunity (correct)

What are the two features of the 3rd Line of Defense?

Specificity and Memory

The specificity of the 3rd Line of Defense allows for a response to multiple pathogens.

False

How do T cells recognize pathogens in Cellular Immunity?

APC identifies antigen of the enemy cell and displays its epitopes. Signup and view all the answers

What is the role of T helper cells (Th cells)?

They secrete interleukins to attract other immune cells. Signup and view all the answers

Which of the following is NOT a way the 3rd Line attacks pathogens?

Physical barriers Signup and view all the answers

Define Memory in Cellular Immunity.

Tm cells retain the ability to combat the particular enemy if there is re-exposure. Signup and view all the answers

Match the following types of immunity with their definitions:

Natural Active Immunity = Makes antibodies following natural exposure to antigens Artificial Active Immunity = Injecting antigens to stimulate an immune response Natural Passive Immunity = Temporary acquisition of antibodies from another person Artificial Passive Immunity = Temporary acquisition of antibodies via blood transfusion or serum Signup and view all the answers

What is a common characteristic of Type I Hypersensitivity?

Immediate response Signup and view all the answers

HIV attacks Th cells, macrophages, and dendritic cells.

True Signup and view all the answers

How is antivenom created?

By injecting venom into a horse to build up immunity, extracting blood, and using the serum. Signup and view all the answers

Study Notes

Immune System Overview

The 3rd line of defense refers to specific immunity, which targets and destroys foreign materials.
Features of the 3rd line include specificity (targeted response to specific pathogens) and memory (ability to remember previous infections).

Specificity

The immune response is tailored to specific pathogens, leading to the development of unique antibodies for each virus.
Limited cross-reactivity exists, where similar pathogens may induce a response due to shared characteristics.

Memory

After initial exposure to a pathogen, memory cells are generated that can recognize and respond rapidly upon re-exposure.
Tm cells coordinate a swift immune response, often neutralizing the pathogen before symptoms appear.

Mechanisms of Pathogen Attack

The immune system employs two main strategies: Cellular Immunity (T cells) and Humoral Immunity (B cells and antibodies).

Cellular Immunity

T cells play a critical role by directly attacking foreign cells, cancer cells, and infected host cells.
Recognition involves Antigen Presenting Cells (APCs) that process and display foreign antigens to T cells, activating them through the Major Histocompatibility Complex (MHC).

Types of T Cells

T Helper (Th) cells stimulate immune responses by attracting other immune cells through interleukins.
Cytotoxic T (Tc) cells carry out direct attacks on pathogen-infected cells using toxic chemicals.

Humoral Immunity

B cells mediate humoral immunity by producing antibodies that neutralize or mark pathogens for destruction.
Responses follow the recognition of an antigen, leading to B cell activation and proliferation into Plasma Cells producing large amounts of antibodies.

Antibody Functions

Antibodies can neutralize pathogens, fix complements, agglutinate enemies, or precipitate immune complexes for removal.
The diversity in antibody types arises from processes like Somatic Hypermutation and Somatic Recombination.

Memory in Humoral Immunity

Elevated antibody titers are maintained post-infection, providing long-term immunity.
B memory cells (Bm cells) enable rapid responses upon re-exposure, enhancing immune efficiency.

Types of Immunity

Natural and Artificial forms exist: Active immunity (long-term) derives from natural exposure or vaccinations, while Passive immunity (temporary) comes from maternal transfer or serum injections.

Antigen Recognition

Antigens trigger immune responses and can be classified into free molecules or cellular antigens based on their association with cells.
Major Histocompatibility Complex (MHC) is crucial for distinguishing self from non-self antigens.

Hypersensitivity Reactions

Hypersensitivity occurs when the immune response is excessive, leading to conditions like allergies, autoimmunity, or alloimmunity (tissue rejection).
Autoimmunity involves the production of autoantibodies targeting self-tissue, often triggered by molecular mimicry or abnormal exposure to antigens.

Immunodeficiency Disorders

Primary immunodeficiencies, like SCID, result from genetic defects affecting immune cell development.
Secondary immunodeficiencies, such as those caused by HIV/AIDS, severely compromise the immune system, increasing vulnerability to infections.

HIV/AIDS

HIV selectively targets CD4+ T helper cells, leading to immune insufficiency.
The latency period can extend for years, complicating prevention and treatment efforts.

Summary of Immune Response Types

Natural Active Immunity: can be established through direct exposure to pathogens.
Artificial Active Immunity: develops from vaccinations.
Natural Passive Immunity: provides temporary immunity through maternal antibodies.
Artificial Passive Immunity: also temporary, achieved through serum injections or blood transfusions.

Description

Test your knowledge of the immune system's third line of defense with these flashcards. Learn about its specificity, memory, and how it identifies and destroys foreign materials. Ideal for students studying immunology.