Immune System

Question 1

What are the two main branches of the immune system?

Answer 1

Innate immunity and adaptive immunity.

Question 2

What is the primary function of the immune system?

Answer 2

To protect the body against pathogens and foreign substances.

Question 3

What are the primary organs of the immune system?

Answer 3

Bone marrow, thymus, spleen, lymph nodes, and tonsils.

Question 4

What are the two types of adaptive immunity?

Answer 4

Humoral immunity (B cells) and cell-mediated immunity (T cells).

Question 5

What is the role of B cells?

Answer 5

To produce antibodies and mediate humoral immunity.

Question 6

What is the function of T helper cells (CD4+)?

Answer 6

To activate B cells and cytotoxic T cells and regulate immune responses.

Question 7

What is the function of cytotoxic T cells (CD8+)?

Answer 7

To kill virus-infected cells and tumor cells.

Question 8

What are antigen-presenting cells (APCs)?

Answer 8

Cells that present antigens to T cells, including dendritic cells, macrophages, and B cells.

Question 9

What is the major histocompatibility complex (MHC)?

Answer 9

A set of proteins that present antigens to T cells for immune recognition.

Question 10

What are the two classes of MHC molecules?

Answer 10

MHC class I (presents to CD8+ T cells) and MHC class II (presents to CD4+ T cells).

Question 11

What is the complement system?

Answer 11

A group of plasma proteins that enhance immune responses by promoting opsonization, inflammation, and cell lysis.

Question 12

What are the three pathways of complement activation?

Answer 12

Classical pathway, alternative pathway, and lectin pathway.

Question 13

What are cytokines?

Answer 13

Signaling proteins that regulate immune responses.

Question 14

What are the primary pro-inflammatory cytokines?

Answer 14

IL-1, IL-6, TNF-alpha.

Question 15

What is the role of interferons?

Answer 15

To inhibit viral replication and enhance immune responses.

Question 16

What are natural killer (NK) cells?

Answer 16

Innate immune cells that kill virus-infected and tumor cells without prior activation.

Question 17

What is passive immunity?

Answer 17

Immunity acquired through transfer of antibodies (e.g., maternal antibodies, antibody therapy).

Question 18

What is active immunity?

Answer 18

Immunity developed after exposure to an antigen (e.g., vaccination or infection).

Question 19

What is an autoimmune disease?

Answer 19

A condition in which the immune system attacks the body’s own tissues.

Question 20

What is immunological tolerance?

Answer 20

The ability of the immune system to distinguish self from non-self and prevent autoimmune reactions.

Question 21

What is the role of memory B cells?

Answer 21

To provide long-term immunity by rapidly producing antibodies upon re-exposure to an antigen.

Question 22

What is hypersensitivity?

Answer 22

An exaggerated immune response that leads to tissue damage.

Question 23

What are the four types of hypersensitivity reactions?

Answer 23

Type I (immediate), Type II (cytotoxic), Type III (immune complex), Type IV (delayed).

Question 24

What is an example of a Type I hypersensitivity reaction?

Answer 24

Allergic reactions (e.g., anaphylaxis, asthma, hay fever).

Question 25

What is an example of a Type II hypersensitivity reaction?

Answer 25

Hemolytic anemia, myasthenia gravis, Graves' disease.

Question 26

What is an example of a Type III hypersensitivity reaction?

Answer 26

Systemic lupus erythematosus (SLE), rheumatoid arthritis.

Question 27

What is an example of a Type IV hypersensitivity reaction?

Answer 27

Contact dermatitis, tuberculosis skin test reaction.

Question 28

What are regulatory T cells (Tregs)?

Answer 28

A subset of T cells that suppress immune responses to prevent autoimmunity.

Question 29

What is the function of IgG?

Answer 29

Provides long-term immunity, crosses the placenta, and enhances phagocytosis.

Question 30

What is the function of IgA?

Answer 30

Protects mucosal surfaces by preventing pathogen attachment.

Question 31

What is the function of IgM?

Answer 31

The first antibody produced in an immune response, effective in complement activation.

Question 32

What is the function of IgE?

Answer 32

Involved in allergic reactions and defense against parasites.

Question 33

What is the function of IgD?

Answer 33

Involved in B cell activation, but its function is not well understood.

Question 34

What are primary immunodeficiencies?

Answer 34

Genetic disorders that impair immune function (e.g., SCID, Bruton's agammaglobulinemia).

Question 35

What are secondary immunodeficiencies?

Answer 35

Acquired conditions that weaken the immune system (e.g., HIV/AIDS, chemotherapy-induced immunosuppression).

Question 36

What is severe combined immunodeficiency (SCID)?

Answer 36

A severe genetic disorder causing absence of functional T and B cells.

Question 37

What is HIV/AIDS?

Answer 37

A viral infection that destroys CD4+ T cells, leading to immunodeficiency.

Question 38

What is the role of the spleen in immunity?

Answer 38

Filters blood, removes old red blood cells, and activates immune responses.

Question 39

What is the function of lymph nodes?

Answer 39

Filter lymph and provide a site for immune cell activation.

Question 40

What is graft-versus-host disease (GVHD)?

Answer 40

An immune reaction in which donor immune cells attack the recipient's tissues after transplantation.

Question 41

What is antigenic drift?

Answer 41

Small genetic changes in a virus that lead to gradual changes in immune recognition.

Question 42

What is antigenic shift?

Answer 42

Major genetic changes in a virus that can result in new strains capable of causing pandemics.

Question 43

What is herd immunity?

Answer 43

Protection from infectious diseases that occurs when a large proportion of the population is immune.

Question 44

What is the difference between a live attenuated and killed vaccine?

Answer 44

Live attenuated vaccines contain weakened pathogens, while killed vaccines contain inactivated pathogens.

Question 45

What is an adjuvant?

Answer 45

A substance added to vaccines to enhance the immune response.

Question 46

What is the function of dendritic cells?

Answer 46

Professional antigen-presenting cells that initiate adaptive immune responses.

Question 47

What is opsonization?

Answer 47

The process by which antibodies or complement proteins coat a pathogen to enhance phagocytosis.

Question 48

What are toll-like receptors (TLRs)?

Answer 48

Receptors on immune cells that recognize pathogen-associated molecular patterns (PAMPs).

Question 49

What is the role of mast cells?

Answer 49

Release histamine and other mediators during allergic reactions.

Question 50

What is an example of molecular mimicry in autoimmune disease?

Answer 50

Rheumatic fever following streptococcal infection.

Question 51

What is the function of the thymus?

Answer 51

Site of T cell maturation and selection.

Question 52

What is the role of neutrophils?

Answer 52

First responders to infections, responsible for phagocytosis and inflammation.

Question 53

What is an example of a vaccine-preventable disease?

Answer 53

Measles, polio, tetanus, influenza.

Question 54

What is the function of eosinophils?

Answer 54

Combat parasitic infections and participate in allergic reactions.

Question 55

What is immunosurveillance?

Answer 55

The immune system's ability to detect and eliminate cancer cells.

Question 56

What is cross-reactivity in immunology?

Answer 56

When an immune response to one antigen also reacts with a structurally similar antigen.

Question 57

What is the function of C-reactive protein (CRP)?

Answer 57

An acute-phase protein that indicates inflammation in the body.

Question 58

What is the role of macrophages?

Answer 58

Phagocytose pathogens, present antigens, and release cytokines.