Immunology Basics Quiz

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Questions and Answers

Define the term immunity as used in immunology.

Immunity refers to the ability of an organism to recognize and defend itself against infectious agents.

What is the opposite of immunity?

Susceptibility

What does the term Antigen refer to?

Antigen is a toxin or other foreign substance that induces an immune response in the body, especially the production of antibodies.

What is the primary function of the immune system?

The immune system consists of various cells, especially lymphocytes, and organs such as the thymus gland, that help provide the host with specific immunity to infectious agents. Signup and view all the answers

Which of the following is an example of innate immunity?

Having inherited genetic resistance to certain diseases Signup and view all the answers

Which of the following is an example of adaptive immunity?

Receiving a vaccine for a specific disease Signup and view all the answers

What is the primary function of phagocytes?

Destroying invading microorganisms Signup and view all the answers

Interferons are proteins that directly kill invading viruses.

False Signup and view all the answers

Which of the following is a key component of the complement system?

All of the above Signup and view all the answers

What is the role of opsonization in the immune response?

Opsonization is a process in which antibodies or complement proteins bind to the surface of pathogens, making them more easily recognizable and phagocytized by immune cells. Signup and view all the answers

The inflammatory response is always harmful to the body.

False Signup and view all the answers

What is the function of lysosomes in phagocytes?

Lysosomes are organelles within phagocytes that contain digestive enzymes, which break down ingested microorganisms. Signup and view all the answers

Match the following types of leukocytes with their primary functions:

Neutrophils = Phagocytic cells that engulf and destroy bacteria Basophils = Release histamine and other inflammatory mediators Eosinophils = Protect against parasitic infections Lymphocytes = Responsible for adaptive immunity Signup and view all the answers

Study Notes

Learning Objectives

Students should be able to explain or identify terminologies in immunology, innate immunity components and reactions, adaptive immunity components and reactions, phagocytosis, molecular defenses, characteristics of inflammation, and the interferon and complement system.

Terminologies

Immunity: An organism's ability to recognize and defend against infectious agents
Susceptibility: Vulnerability to harm from infectious agents, the opposite of immunity
Antigen: A foreign substance that induces an immune response, especially antibody production.
Immune System: Composed of cells (chiefly lymphocytes) and organs (like the thymus) to provide specific immunity against infectious agents.

Differences Between Antigen and Antibody

Antigen: A substance that stimulates an immune response, like a bacterial cell. It has epitopes (antigenic determinants).
Antibody: The body's response to an antigen.

Types of Immunity

Innate Immunity (Genetic): Genetically determined characteristics provide resistance to many infectious agents.
Adaptive Immunity (Acquired): Immunity developed other than heredity. Naturally acquired through disease, artificially acquired through vaccines or immunizations.

Toxoids

Toxoid is a normally toxic substance that has been treated to lose its toxicity yet maintains the ability to stimulate antibody production.
Toxoids are components or toxins from pathogens and are used to immunize against diseases such as diphtheria, tetanus, and cholera.

Innate and Adaptive Immunity

Adaptive Defenses: Target specific agents like viruses and bacteria.
Innate Defenses: Respond to all types of invading agents.

Adaptive Immunity

Responds to antigens by producing antibodies.
Involves the activation of lymphocytes (specific immune system cells).
Antibodies and cellular responses are more efficient against repeat infections.

Innate Immunity

Physical barriers: Skin and mucus membranes protect against pathogens.
Chemical barriers: Substances like sweat, sebum, and stomach acid create unfavorable conditions for pathogens.
Cellular defenses: Cells in the body that engulf and destroy pathogens.
Inflammation: Body's response to injury or infection characterized by redness, swelling, heat and pain.
Fever: Body temperature rise to fight and inhibit pathogens.
Molecular defenses: Proteins like interferons and complement, which destroy or block pathogens.

Physical Barriers

Skin and mucous membranes protect internal body organs from injury and pathogens.
Lining of the body surfaces that secrete chemicals, like human beta-defensin-2 on the skin.

Granulocytes

Granulocytes are leukocytes with a lobed nucleus and granular cytoplasm.
Basophils, mast cells, eosinophils and neutrophils (polymorphonuclear leukocytes) are types of granulocytes.

Agranulocytes

Agranulocytes are leukocytes lacking granules.
Monocytes and lymphocytes are examples.

Phagocytes

Cells that engulf and destroy cellular debris, dead cells and pathogens.
Macrophages are large phagocytes that can engulf larger particles.

Phagocytosis

A process where phagocytes ingest microorganisms and debris.
Steps involved: finding, adhering, ingesting and digesting the microorganisms.

Inflammation

Inflammatory response: The body's defensive reaction to tissue damage caused by microbes.
Characterized by redness, swelling, heat, pain, and possibly fever.

Molecular Defenses (Interferons and Complement)

Interferons: Small proteins that inhibit viral replication and enhance other immune functions.
Complement system: A group of proteins that enhance phagocytosis, kill pathogens directly, and promote inflammation.

Natural Killer Cells (NK Cells)

Increase activity via exposure to interferons and cytokines.
Recognize specific glycoproteins on infected cells and trigger their destruction.

Complement System

Set of proteins that enhance immune responses, including phagocytosis and pathogen death.
Works as a cascade, amplifying effects.

Opsonization

Antibodies coat pathogens, improving phagocytosis efficiency.
Complement components like C3b enhance phagocytosis.

Immune Cytolysis

Complement system proteins can directly destroy cells, creating pores and disrupting cellular function (through membrane attack complexes).

Summary of Body's Non-Specific Defenses

Physical Barriers: Prevent pathogen entry.
Phagocytes: Eliminate pathogens and debris.
Extracellular Killing: Destroy abnormal cells.
Inflammatory Response: Local reaction to tissue damage.
Fever: Body temperature rise.
Interferons: Limit pathogen spread.
Complement System: Enhances various immune functions.

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Description

Test your understanding of the key concepts in immunology, including innate and adaptive immunity, phagocytosis, and the immune response. This quiz will cover important terminologies and the functions of the immune system components. Enhance your knowledge of how the body defends against infectious agents.