System Day 1and 2 AI Question Immune System Fundamentals

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Questions and Answers

What is the primary function of antigens?

To recognize foreign invaders and elicit specific responses from hosts (correct)

To produce antibodies and activate phagocytes

To initiate the destruction of associated organisms

To patrol the blood and lymph and kill own cells

What is the main difference between neutrophils and macrophages?

Their size, with macrophages being larger

Their ability to circulate in the blood

Their function, with neutrophils healing tissue and macrophages attacking antigens

Their lifespan, with neutrophils dying after attacking antigens (correct)

What is the role of Natural Killer (NK) cells?

To provide the first line of defense against microbes

To produce antibodies and activate phagocytes

To patrol the blood and lymph and activate the adaptive response

To recognize and destroy infected cells and tumor cells (correct)

What is the purpose of the innate response?

To provide an immediate, non-specific defense against infection Signup and view all the answers

What is the function of phagocytes?

To engulf and digest foreign particles and microbes Signup and view all the answers

What is the role of epitopes?

To bind to antibodies and initiate the destruction of associated organisms Signup and view all the answers

What is the purpose of antimicrobial substances?

To tend to kill or damage microbes Signup and view all the answers

What is the main difference between the innate and adaptive responses?

Their specificity, with the adaptive response being specific Signup and view all the answers

Which type of immunity develops through direct exposure to an antigen?

Active natural immunity Signup and view all the answers

What is the primary function of B-lymphocytes?

To recognize and eliminate antigens through the production of antibodies Signup and view all the answers

What is the function of plasma cells?

To produce and secrete antibodies Signup and view all the answers

What is the primary function of IgA?

To be present in breast milk and provide protection to neonates Signup and view all the answers

What is the function of antigen-presenting cells?

To break down and present epitopes on their surfaces Signup and view all the answers

What is the function of T-helper cells?

To regulate and upregulate the immune response Signup and view all the answers

What is the function of regulatory T-cells?

To downregulate and suppress the immune response Signup and view all the answers

What is the term for the ability to distinguish between self- and non-self antigens?

Immunologic self-tolerance Signup and view all the answers

What is the term for the immune response against the body's own tissues?

Autoimmunity Signup and view all the answers

What is the term for the binding of autoantibodies with self-molecules?

Immune complexes Signup and view all the answers

What is the primary antigen involved in Erythroblastosis Fetalis?

Rh factor Signup and view all the answers

Which type of hypersensitivity reaction is characterized by the formation of antigen-antibody complexes?

Type III - Immune Complex Mediated Hypersensitivity Signup and view all the answers

What is the primary mediator of Type I - Immediate Hypersensitivity reactions?

IgE Signup and view all the answers

Which of the following is an example of a Type II - Antibody Mediated Hypersensitivity reaction?

Autoimmune Hemolytic Anemia Signup and view all the answers

What is the primary mechanism of tissue damage in Type IV - Delayed or Cell-Mediated Hypersensitivity reactions?

Infiltration of tissue by lymphocytes and macrophages Signup and view all the answers

Which type of hypersensitivity reaction is responsible for Polyarteritis Nodosa?

Type III - Immune Complex Mediated Hypersensitivity Signup and view all the answers

What is the primary role of IgE in hypersensitivity reactions?

Release of inflammatory mediators from sensitized mast cells Signup and view all the answers

Which of the following is an example of a Type III - Immune Complex Mediated Hypersensitivity reaction?

Glomerulonephritis Signup and view all the answers

What is the primary mechanism of Type II - Antibody Mediated Hypersensitivity reactions?

Direct antibody-mediated cytotoxicity Signup and view all the answers

Which type of hypersensitivity reaction is responsible for Contact Dermatitis?

Type IV - Delayed or Cell-Mediated Hypersensitivity Signup and view all the answers

Study Notes

Immune System

The immune system is the body's defense against foreign invaders, providing protection from disease and infectious disease.
Immunity is based on the capacity to recognize foreign invaders (non-self).

Microbes and Antigens

A microbe is a type of microorganism that is too small to see with the unaided eye, such as bacteria, viruses, and fungi.
A microbe that causes disease is called a pathogen.
An antigen is a large molecule (usually a protein or polysaccharide) on a cell surface that elicits a specific response from the host.
An epitope is a part of an antigen molecule to which an antibody attaches.

Immune Response

The immune response is the collective, coordinated response of the cells and molecules of the immune system to protect against infectious disease.
There are two types of immune responses: innate and adaptive.

Innate Response

The innate response is a non-specific, initial line of defense that provides an effective barrier to microbes.
It is something we are born with and is the first line of defense against infection.

Adaptive Response

The adaptive response is a specific response that develops with exposure to various organisms and substances that the immune system finds threatening.
It is very effective and involves the activation of immune cells, such as B-cells and T-cells.

B-Cells and T-Cells

B-cells (B-lymphocytes) are key players in humoral immunity, recognizing microbes and antigens, and producing antibodies.
T-cells (T-lymphocytes) are responsible for cell-mediated/cellular immunity and work via cell-to-cell contact or by secreting messenger compounds that communicate with immune system cells.

Types of T-Cells

T-Helper cells (CD-4 cells) upregulate and are key regulatory cells of the immune system.
Regulatory T-cells (Tregs) downregulate and suppress/modify immune responses.
T-cytotoxic cells (CD-8 cells) destroy identified/presented antigens and kill virus-infected cells.

Antigen Presenting Cells

These cells bind to and/or break down antigens and present epitopes on their surfaces, or alter the antigen to make it more recognizable.

Humoral Immunity and Immunoglobulins

Humoral immunity involves the production of antibodies by B-cells.
There are different types of immunoglobulins (Ig), such as IgG, IgA, and IgM, each with specific functions.

Active and Passive Immunity

Active immunity develops through direct exposure to an antigen.
Passive immunity is passed from a mother to fetus, or injected from one system to another.

Autoimmune Diseases

Immunologic self-tolerance is the ability to distinguish between self- and non-self antigens.
Autoimmune diseases, such as Rheumatoid Arthritis, Multiple Sclerosis, and Myasthenia Gravis, occur when the immune system mounts a response against the body's own tissues.

Hypersensitivity Disorders

Hypersensitivity disorders occur when the immune system overreacts to antigens, leading to inflammation and tissue damage.
There are four types of hypersensitivity reactions: Type I (Immediate), Type II (Antibody-mediated), Type III (Immune Complex-mediated), and Type IV (Delayed or Cell-mediated).

Type I Hypersensitivity

Mediated by IgE, leading to the release of inflammatory mediators from sensitized mast cells.
Examples include allergic rhinitis, asthma, urticaria, angioedema, and gastrointestinal food allergies.

Type II Hypersensitivity

Mediated by IgM or IgG, directed against target antigens on cell surfaces or in extracellular tissue.
Examples include hemolysis, erythroblastosis fetalis, autoimmune hemolytic anemia, blood transfusion reactions, and autoimmune thrombocytopenia.

Type III Hypersensitivity

Mediated by the formation of antigen-antibody complexes, complement fixation, and localized inflammation.
Examples include the Arthus reaction, serum sickness, glomerulonephritis, and polyarteritis nodosa.

Type IV Hypersensitivity

Mediated by specifically sensitized T-lymphocytes, manifesting as sub-acute or chronic inflammation.
Examples include contact dermatitis and graft rejection.

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Description

Understand the basics of the immune system, including immunity, immune response, and microorganisms such as pathogens. Learn about antimicrobial substances and their effects.