Immunity and Defense Mechanisms Quiz

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Questions and Answers

What method provides natural passive immunity to a child?

Injection of synthetic antibodies

Vaccination with live pathogens

Direct contact with infected individuals

Breastfeeding from the mother (correct)

What is a defining characteristic of passive immunity?

It relies solely on the environment for antibodies

It provides long-lasting immunity

The body generates its own antibodies over time

It gives immediate but short-term protection (correct)

Which of the following is an example of artificial passive immunity?

Antitetanus serum injection (correct)

Antibodies provided through colostrum

Exposure to a pathogen in childhood

Vaccination with attenuated virus

Why does passive immunity not confer long-term protection?

The body cannot produce its own antibodies in this case Signup and view all the answers

During which period do mothers pass antibodies to their fetuses?

During the prenatal period Signup and view all the answers

What triggers the production of antibodies in natural active immunity?

Recovery from an infection Signup and view all the answers

Which statement about artificial active immunity is accurate?

It involves a booster dose to increase antibody production. Signup and view all the answers

What is the primary function of lymphocytes in the context of natural active immunity?

To produce antibodies Signup and view all the answers

What happens to antibody levels after the first vaccine injection in artificial active immunity?

They are often low and insufficient for protection. Signup and view all the answers

Which example is associated with natural active immunity?

Natural infection Signup and view all the answers

What is an essential part of artificial active immunity?

Vaccine administration Signup and view all the answers

How is natural passive immunity acquired?

Transfer of antibodies from mother to fetus Signup and view all the answers

What role does a booster dose play in immunity?

It enhances the level of antibody production. Signup and view all the answers

What is immunity primarily concerned with?

The body's ability to fight infections Signup and view all the answers

Which of the following is NOT a type of pathogen?

Antibodies Signup and view all the answers

What role do antigens play in the immune response?

They stimulate the immune response by the body Signup and view all the answers

Which statement about the first line of defense is true?

It includes physical and chemical barriers. Signup and view all the answers

What are antibodies primarily produced by?

Lymphocytes Signup and view all the answers

What is lysozyme's function in the immune system?

To dissolve and destroy certain bacteria Signup and view all the answers

Which of the following statements accurately describes pathogens?

They are microorganisms that cause diseases. Signup and view all the answers

Which line of defense is not specific and prevents pathogens from entering the body?

The first line of defense Signup and view all the answers

What is the primary method through which artificial passive immunity is acquired?

Injection of antiserum Signup and view all the answers

Which of the following describes a key difference between artificial active and passive immunity?

Active immunity lasts for a long period while passive is temporary. Signup and view all the answers

What is the purpose of injecting a vaccine in artificial active immunity?

To prevent future infections Signup and view all the answers

During which stage is artificial passive immunity typically administered?

Before infection occurs Signup and view all the answers

How does HIV primarily enter the human body?

Through the transfer of body fluids Signup and view all the answers

Which of the following statements about AIDS is accurate?

It causes a progressive destruction of the immune system. Signup and view all the answers

What condition may occur in infants from HIV-infected mothers?

HIV infection during pregnancy or breastfeeding Signup and view all the answers

What is the effect of artificial passive immunity compared to artificial active immunity?

Passive immunity does not require an immune response. Signup and view all the answers

What can lead to a weakened immune system in AIDS patients?

Destruction of lymphocytes by HIV Signup and view all the answers

Which statement about antibody injection in passive immunity is correct?

It is given when there's a high risk of severe infection. Signup and view all the answers

What is the role of mucus in the respiratory tract?

It traps bacteria and pathogens from entering the lungs. Signup and view all the answers

Which component of the immune response is responsible for phagocytosis?

Phagocytes such as neutrophils and monocytes Signup and view all the answers

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

Bind to antigens and facilitate their destruction. Signup and view all the answers

What process describes how antibodies bind to toxins produced by bacteria?

Neutralization Signup and view all the answers

How does active immunity differ from passive immunity?

Active immunity is acquired through direct exposure to pathogens. Signup and view all the answers

What triggers the inflammatory response in the body?

The presence of harmful microorganisms or toxins. Signup and view all the answers

What function does hydrochloric acid serve in the immune system?

It destroys bacteria in food and drinks. Signup and view all the answers

What happens to the lymph nodes during an immune response?

They become inflamed due to accumulating lymphocytes. Signup and view all the answers

Which statement regarding the skin's role in immunity is true?

The skin is a physical barrier that prevents pathogen entry. Signup and view all the answers

What is the role of memory cells in the immune system?

They make antibodies immediately upon re-exposure to the same pathogen. Signup and view all the answers

Which immune response mechanism does precipitation refer to?

The formation of an insoluble complex that is removed by phagocytosis. Signup and view all the answers

What impact does fever have on the immune system?

It enhances phagocytic activity. Signup and view all the answers

In what way does skin sweat contribute to immunity?

It contains enzymes that break down bacterial cell walls. Signup and view all the answers

What type of immunity results from vaccination?

Active artificial immunity Signup and view all the answers

Study Notes

Immunity

The body's ability to defend against infections caused by pathogens.
It involves a complex system of defense mechanisms.

Pathogens

Microorganisms that cause diseases.
Examples: Bacteria, Viruses, Parasites.
Must infect body cells to cause diseases.

Antigens

Foreign particles that enter the body and stimulate the immune response.
Recognized by the body's defense system as foreign substances.

Antibodies

Proteins produced by lymphocytes to destroy antigens.
Found on the surface of lymphocytes or released into the blood plasma.
The interaction between antibodies and antigens is known as the immune response.

Lines of Defense

Three main lines of defense against disease.
First Line of Defense: Physical and chemical barriers that prevent pathogens from entering the body (e.g., skin, mucous membranes, lysozyme).
Second Line of Defense: Non-specific mechanisms that fight pathogens that have entered the body (e.g., fever, phagocytosis, inflammation).
Third Line of Defense: Specific immune response involving lymphocytes producing antibodies (e.g., B and T lymphocytes).

First Line of Defense

Lysozyme

Antimicrobial protein that destroys bacteria.
Found in tears, nasal mucus, and saliva.

Mucous Membrane

Lines the respiratory tract.
Secretes mucus that traps pathogens.

Blood Clotting

Prevents bacteria from entering through wounds.

Hydrochloric Acid

In the stomach, destroys bacteria in food and drinks.

Skin

Physical barrier that prevents pathogen entry due to its thickness.
Continuous shedding of dead skin cells makes it difficult for microorganisms to grow.
Secretes sebum (oil and acid) that inhibits the growth of microorganisms.
Sweat contains lysozyme.

Second Line of Defense

Non-specific defense mechanisms.

Fever

Increases phagocytic activity and fights against microorganisms.

Phagocytosis

Process where phagocytes (neutrophils and monocytes) engulf and digest pathogens and dead cells.
Phagocytes move to infected areas and enter tissue fluid through capillary pores.
They contain lysozyme to digest pathogens.

Inflammation

Immediate response to infection.
Destroys and neutralizes harmful microorganisms and toxins.

Third Line of Defense

Specific immune response involving lymphocytes.

Lymphocytes

Produce antibodies and accumulate in lymph nodes during infection.
Two types: T lymphocytes and B lymphocytes.
T lymphocytes attack cells infected by pathogens.
B lymphocytes produce antibodies that target specific antigens.

Lymph Nodes

Contain lymphocytes and macrophages.
Filter bacteria, dead tissues, and foreign particles.

Memory Cells

Produced by B lymphocytes as a result of encounters with specific pathogens.
Rapidly produce antibodies upon re-exposure to the same pathogen.

Antibody Actions

Neutralization: Antibodies bind with toxins produced by bacteria, neutralizing them.
Agglutination: Antibodies coagulate pathogens, making them easier for phagocytes to destroy.
Precipitation: Antibodies react with dissolved antigens to form an insoluble complex (precipitate) that is easily destroyed by phagocytes.
Lysis: Antibodies bind to antigens on bacteria causing cell destruction.

Immunity Types

Active Immunity: Immune system produces its own antibodies in response to antigens.
- Natural Active Immunity: Acquired after recovering from an infection.
- Artificial Active Immunity: Acquired through vaccination.
Passive Immunity: Body receives antibodies from an external source.
- Natural Passive Immunity: Acquired from mother to fetus during pregnancy or through breastfeeding (transferred through placenta or breastmilk).
- Artificial Passive Immunity: Acquired through injection of antiserum containing pre-made antibodies.

Vaccines

Suspensions of weakened, dead, or non-virulent pathogens.
Stimulate the immune system to produce antibodies without causing the disease.
May require booster doses to maintain immunity.

HIV and AIDS

HIV (Human Immunodeficiency Virus): Virus that attacks the human immune system.
AIDS (Acquired Immunodeficiency Syndrome): Condition caused by HIV infection that weakens the immune system.

HIV Transmission

Through body fluids like blood and semen.
Can transfer from mother to child during pregnancy, birth, or breastfeeding.
Also spread through contaminated needles and blood transfusions.

Symptoms of AIDS

May not be visible for several years.
Chronic diarrhea, fungal infections, and other opportunistic infections develop later.
AIDS weakens the immune system, making individuals susceptible to other diseases.
Ultimately, the immune system fails, and the individual dies from infections.

Differences between Artificial Active and Passive Immunity

Aspect	Artificial Active Immunity	Artificial Passive Immunity
Acquired through	Vaccine injection	Antiserum injection
Injected substance	Vaccine (weakened, dead, or non-virulent pathogens)	Antiserum (serum containing specific antibodies)
Purpose	Prevention	Treatment or immediate protection
Effect	Does not give immediate protection	Gives immediate protection
Immunity period	Long lasting	Temporary
When injection is given	Before infection	Advance if there is a high risk of infection, or immediately after infection
Antibody production	Antibodies are produced by the lymphocytes	Antibodies are obtained from antiserum
Need for booster doses	Yes, to maintain immunity levels	No, unless the antibody level drops below the level of immunity

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Description

Test your knowledge on the immune system and its various components, including pathogens, antigens, and antibodies. This quiz will explore the body's lines of defense against diseases and how it protects itself from infections.