Week 6: Lymphoid & Immune System

Question 1

T/F: The lymphatic system plays an important role in the regulation of interstital fluid and blood volume.

Answer 1

True

Question 2

T/F: White blood cells can only be found in lymphoid organs and tissues.

Answer 2

False

Question 3

T/F: Innate defences are non-specific defences because they will destroy ANY type of foreign material.

Answer 3

True

Question 4

T/F: Cytokines are secreted by white blood cells to activate white blood cell.

Answer 4

True

Question 5

Phagocytose and destroy foreign material via lysosomal enzymes - ____________________

Answer 5

Phagocytose and destroy foreign material via lysosomal enzymes - macrophages and neutrophils

Question 6

Identify which of the following are the first line of defence.

Macrophages and Neutrophils.
Intact skin and mucous membranes.
Pyrogens.
Normal flora.
Complement.
Sweat, saliva and tears.

Answer 6

Intact skin and mucous membranes.
Normal flora.
Sweat, saliva and tears.

Question 7

Inhibit with viral replication -____________________

Answer 7

Inhibit with viral replication - Interferons

Question 8

Induce fever - ______________________

Answer 8

Induce fever - Pyrogens

Question 9

Directly destroy cellular target by forming a membrane attack complex -

Answer 9

Directly destroy cellular target by forming a membrane attack complex - Complement

Question 10

Isolates and removes foreign materials, repairs damaged tissues - _______________

Answer 10

Isolates and removes foreign materials, repairs damaged tissues - Immune response

Question 11

T/F: Adaptive defences are present and active from birth.

Answer 11

False

Question 12

T/F: The foreign invader that activates the body’s adaptive defences is called an antigen.

Answer 12

True

Question 13

T/F: Immunocompetence and self-tolerance are two characteristics of T and B cells.

Answer 13

True

Question 14

Match the adaptive defence to its function.

1. Turns on an immune response -
2. Directly destroys cellular antigens -
3. Differentiates into plasma cells -
4. Produces and secretes antibodies -
5. Inactivates and tags antigens for destruction -

Plasma cells
Cytotoxic T cell
Helper T cell
B cell
Antibodies

Answer 14

1. Turns on an immune response - Helper T cell
2. Directly destroys cellular antigens - Cytotoxic T cell
3. Differentiates into plasma cells - B cell
4. Produces and secretes antibodies - Plasma cells
5. Inactivates and tags antigens for destruction - Antibodies

Question 15

Identify which of the following is characteristic of a primary immune response.

Response produces a large amount of IgG antibodies.
Rapid, long-lasting response.
Slow, short lived response.
Response produces a small amount of IgM and IgG antibodies.
Produces memory T and B cells.

Answer 15

Slow, short lived response.
Response produces a small amount of IgM and IgG antibodies.
Produces memory T and B cells.

Question 16

T/F: Immunodeficiency diseases arise because the body’s immune defences are too vigorous and attack a harmless antigen that most people can tolerate.

Answer 16

False

Question 17

T/F: Type 1 diabetes and rheumatoid arthritis are examples of an autoimmune disease.

Answer 17

True

Question 18

Which of the following is involved in an allergic reaction.

Autoantibodies.
IgE
Histamine.
IgA
Cytotoxic T cells.
Mast cells and Basophils.

Answer 18

IgE
Histamine.
Mast cells and Basophils.

Question 19

T/F: Lymph is excess intracellular fluid.

Answer 19

False

Question 20

T/F: Lymph flows from the tissues back to the venous circulation via lymph vessels.

Answer 20

True

Question 21

T/F: Lymph nodes filter lymph and prevent foreing materials from entering the blood and spreading throughout the body.

Answer 21

True

Question 22

Innate defences:

a) provide protection against a specific foreign invader

b) only destroy bacterial-infected body cells

c) develop throughout life

d) are present and active from birth

Answer 22

d) are present and active from birth

Question 23

Lysozyme is an enzyme that destroys bacteria. Identify the innate defences that contain this enzyme.

Tears.
Saliva.
Sebum.
Mucus.
Gastric juice.
Sweat.

Answer 23

Tears.
Saliva.
Sweat

Question 24

Macrophages and neutrophils ________ and destroy foreign materials by ____________ enzymes.

Answer 24

Macrophages and neutrophils PHAGOCYTOSE and destroy foreign materials by LYSOSOMAL enzymes.

Question 25

Natural killer cells destroy virus-infected cells and cancerous cells by releasing __________ to induce _____________.

Answer 25

Natural killer cells destroy virus-infected cells and cancerous cells by releasing PERFORINS AND GRANZYMES to induce APOPTOSIS.

Question 26

Interferons are cytokines that inhibit _______________.

Answer 26

Interferons are cytokines that inhibit VIRAL REPLICATION.

Question 27

Complement refers to a group of proteins that destroy cellular enemies such as bacteria by forming a ___________ which induces __________________.

Answer 27

Complement refers to a group of proteins that destroy cellular enemies such as bacteria by forming a MEMBRANE ATTACK COMPLEX which induces CELL LYSIS.

Question 28

___________ are a group of proteins which induce fever.

Answer 28

PYROGENS are a group of proteins which induce fever.

Question 29

Helper T cells:

A) release cytokines that turn off a cellular and humoral immune response

B) release cytokines that help turn on a cellular and humoral immune response

C) directly kill all types of anitgens

D) directly stimulate plasma cells to produce antibodies

Answer 29

B) release cytokines that help turn on a cellular and humoral immune response

Question 30

Cytotoxic T cells:

A) destroy cellular antigens by releasing perforins and granzymes

B) are only involved in a secondary immune response

C) phagocytose and destroy all types of anitgens

D) mediate a humoral immune response

Answer 30

A) destroy cellular antigens by releasing perforins and granzymes

Question 31

B cells:

A) mediate a cellular immune response

B) release cytokines to directly destory cellular antigens

C) produce and secrete antibodies

D) differentiate into plasma cells which produce antibodies

Answer 31

D) differentiate into plasma cells which produce antibodies

Question 32

The Human Immunodeficiency Virus (HIV):

A)stimulates mast cells and basophils to release histamine
B) infects and destroys cytotoxic T cells
C) inhibits a cellular immune response, but not a humoral immune response
D) infects and destroys helper T cells

Answer 32

D) infects and destroys helper T cells

Question 33

Define:

Lymphoid System

Answer 33

The network of cells, tissues, and organs that work together to protect the body from harmful materials and diseases, including abnormal body cells that could lead to cancers.

Question 34

Define:

Immune System

Answer 34

A complex system of biological structures and processes that protect the body from pathogens and other harmful materials through cell-to-cell interactions and immune responses.

Question 35

Define:

Pathogen

Answer 35

Any microorganism, such as a virus, bacteria, fungus, or worm, that can cause disease within the host body.

Question 36

Define:

Inflammation

Answer 36

A natural immune response characterized by redness, heat, swelling, and pain, often occurring in response to infection or injury.

Question 37

Define:

Fever

Answer 37

An elevated body temperature that is a common immune response to infection, helping the body fight off pathogens.

Question 38

Define:

Transplants

Answer 38

The medical procedure of transferring cells, tissues, or organs from one body to another, which requires careful management of immune responses to prevent rejection.

Question 39

Define:

Immunodeficiency Diseases

Answer 39

Conditions where the immune system is weakened or not functioning properly, making the body more susceptible to infections and diseases.

Question 40

Define:

Autoimmune Diseases

Answer 40

Diseases in which the immune system mistakenly attacks the body’s own cells, such as rheumatoid arthritis and type 1 diabetes.

Question 41

Define:

Viruses

Answer 41

Pathogens that infect and replicate within body cells, often leading to the destruction of the infected cells.

Question 42

Define:

Worms

Answer 42

Parasitic organisms that live in the intestines and cause various diseases in their host.

Question 43

Define:

Bacteria

Answer 43

Microorganisms that multiply in body fluids and produce toxins, leading to damage of cells, tissues, and organs.

Question 44

Define:

Lymphoid System

Answer 44

The combined components of the lymphatic system, lymphoid organs and tissues, white blood cells, and cytokines that work together to protect the body from harmful materials and diseases.

Question 45

Define:

Lymphatic System

Answer 45

A network of lymphatic capillaries, vessels, lymph nodes, and the fluid called lymph, responsible for circulating body fluids, removing foreign materials, and transporting white blood cells to infection sites.

Question 46

Define:

Lymph

Answer 46

Excess interstitial fluid collected by lymphatic capillaries, which is then circulated through the lymphatic system to maintain blood volume and pressure, and to remove foreign materials.

Question 47

Define:

Interstitial Fluid

Answer 47

Fluid that surrounds body cells, produced by the balance of hydrostatic and colloid osmotic pressures in capillaries, with excess being collected by lymphatic capillaries as lymph.

Question 48

Define:

Hydrostatic Pressure

Answer 48

The pressure exerted by fluid within blood vessels, delivering interstitial fluid to body tissues.

Question 49

Define:

Colloid Osmotic Pressure

Answer 49

The pressure exerted by proteins in blood plasma, which pulls interstitial fluid back into the blood vessels.

Question 50

Define:

Lymphatic Capillaries

Answer 50

Tiny, thin-walled vessels located between body cells that collect interstitial fluid, white blood cells, and foreign materials, allowing them to enter the lymphatic system.

Question 51

Define:

Lymph Nodes

Answer 51

Small, bean-shaped structures located along lymphatic vessels that filter lymph, trapping and removing foreign materials, and facilitating an immune response.

Question 52

Define:

Lymphedema

Answer 52

A condition where excess interstitial fluid accumulates in body tissues due to an impaired lymphatic system, leading to swelling and increased risk of infection.

Question 53

Define:

Elephantiasis

Answer 53

A tropical disease caused by parasitic worms blocking lymphatic vessels, leading to severe swelling, particularly in the lower limbs and scrotum.

Question 54

Define:

White Blood Cells (WBCs)

Answer 54

Cells that are part of the immune system, responsible for defending the body against foreign materials, including bacteria, viruses, parasites, and cancerous cells.

Question 55

Define:

Cytokines

Answer 55

Communication molecules produced by white blood cells that recruit or activate specific white blood cells to respond to infections or destroy foreign materials.

Question 56

Define:

Interferons

Answer 56

A type of cytokine involved in the immune response, particularly in inhibiting viral replication within host cells.

Question 57

Define:

Interleukin-1 (IL-1)

Answer 57

A cytokine that plays a key role in the regulation of immune and inflammatory responses to infections or injuries.

Question 58

Define:

Interleukin-2 (IL-2)

Answer 58

A cytokine that stimulates the growth and activity of white blood cells, particularly T cells, as part of the immune response.

Question 59

Define:

Primary Lymphoid Organs

Answer 59

Organs, such as red bone marrow and the thymus, where white blood cells are produced.

Question 60

Define:

Secondary Lymphoid Organs and Tissues

Answer 60

Organs and tissues, including lymph nodes, spleen, tonsils, appendix, and those lining the gastrointestinal and urinary tracts, where foreign materials are trapped, destroyed, and immune responses are activated.

Question 61

Define:

Innate Defenses (Non-Specific Defenses)

Answer 61

The immune system’s initial defense mechanisms that protect against any type of foreign material before it can enter or spread throughout the body.

Question 62

Define:

Adaptive Defenses (Specific Defenses)

Answer 62

The immune system’s targeted response to specific pathogens that have spread and invaded the body, involving the generation of an immune response.

Question 63

Define:

Surface Barriers

Answer 63

The body’s first line of defense against pathogens, including physical and chemical barriers like skin and mucous membranes.

Question 64

Define:

Protective Proteins

Answer 64

Proteins found within the body that play a role in the immune system’s internal defenses, helping to identify and neutralize pathogens.

Question 65

Define:

Immune Response

Answer 65

The body’s third line of defense, where the immune system generates a specific response to eliminate invading pathogens.

Question 66

Define:

Physical Barriers

Answer 66

Structural defenses like the skin and mucous membranes that create a barrier to block foreign materials from penetrating the body.

Question 67

Define:

Mucous Membranes

Answer 67

Thin layers of tissue lining body tracts (e.g., gastrointestinal, respiratory, urinary, and reproductive tracts) that form a barrier to prevent the entry of foreign materials.

Question 68

Define:

Epithelial Cells

Answer 68

Cells forming the outer layer of the skin and mucous membranes, providing a protective barrier against foreign materials.

Question 69

Define:

Accessory Structures

Answer 69

Structures like hair and cilia that assist in trapping and removing foreign materials from the body’s surfaces.

Question 70

Define:

Mucociliary Escalator

Answer 70

A mechanism in the respiratory tract where cilia move mucus and trapped foreign materials away from the lungs toward the throat to be expelled or swallowed.

Question 71

Define:

Normal Flora

Answer 71

Beneficial bacteria that colonize various body surfaces and cavities, inhibiting the growth of pathogens by competing for nutrients and space.

Question 72

Define:

Chemical Barriers

Answer 72

Body secretions such as sweat, saliva, tears, sebum, mucus, and gastric juice that cleanse and protect body surfaces by destroying or trapping foreign materials.

Question 73

Define:

Lysozyme

Answer 73

An enzyme found in sweat, saliva, and tears that specifically targets and destroys bacteria.

Question 74

Define:

Sebum

Answer 74

An oily, acidic secretion produced by sebaceous glands that covers the skin, inhibiting the growth of pathogens and being toxic to some bacteria.

Question 75

Define:

Mucus

Answer 75

A sticky, viscous fluid that lines the gastrointestinal and respiratory tracts, trapping foreign materials that enter internal passageways.

Question 76

Define:

Gastric Juice

Answer 76

A digestive fluid in the stomach containing hydrochloric acid and the enzyme pepsin, which destroys foreign materials that enter the stomach.

Question 77

Define:

First Line of Defense

Answer 77

The body’s initial protection against foreign materials, consisting of physical and chemical barriers that prevent entry.

Question 78

Define:

Second Line of Defense

Answer 78

Internal defense mechanisms, including white blood cells, protective proteins, and inflammatory responses, that activate when the first line of defense is breached.

Question 79

Define:

White Blood Cells

Answer 79

Immune cells, such as macrophages, neutrophils, and natural killer cells, that play key roles in defending the body against invaders.

Question 80

Define:

Macrophages

Answer 80

Phagocytic white blood cells that engulf and digest foreign materials, including bacteria, viruses, and cancer cells.

Question 81

Define:

Neutrophils

Answer 81

Phagocytic white blood cells that target and consume bacteria and other foreign materials, often indicating bacterial infection when elevated.

Question 82

Define:

Natural Killer (NK) Cells

Answer 82

A type of white blood cell that detects and destroys virus-infected and cancerous cells by inducing apoptosis through the release of perforins and granzymes.

Question 83

Define:

Perforins

Answer 83

Proteins released by NK cells that create pores in the target cell membrane, allowing destructive enzymes to enter.

Question 84

Define:

Granzymes

Answer 84

Enzymes released by NK cells that induce apoptosis, causing the target cell to self-destruct.

Question 85

Define:

Interferons

Answer 85

Cytokines produced by white blood cells and virus-infected cells that interfere with viral replication and activate macrophages and NK cells.

Question 86

Define:

Complement System

Answer 86

A group of plasma proteins that enhance immune responses by promoting phagocytosis, recruiting immune cells, and directly destroying pathogens through the formation of membrane attack complexes.

Question 87

Define:

Opsonization

Answer 87

A process where complement proteins coat foreign materials, making them easier for macrophages and neutrophils to identify and consume.

Question 88

Define:

Inflammatory Response

Answer 88

A reaction to tissue damage characterized by heat, redness, swelling, pain, and loss of function, which helps localize and eliminate foreign materials and repair tissues.

Question 89

Define:

Histamine

Answer 89

A chemical released during inflammation that causes blood vessels to dilate and become more permeable, facilitating immune cell movement to the site of injury.

Question 90

Define:

Prostaglandins

Answer 90

Chemicals released during inflammation that contribute to pain and swelling by increasing blood vessel permeability and amplifying the inflammatory response.

Question 91

Define:

Pyrogens

Answer 91

Substances, including interleukin-1 and bacterial toxins, that induce fever by resetting the body’s hypothalamic thermostat to a higher temperature.

Question 92

Define:

Apoptosis

Answer 92

A process of programmed cell death induced by immune cells to eliminate virus-infected or cancerous cells.

Question 93

Define:

Membrane Attack Complex

Answer 93

A structure formed by complement proteins that creates holes in the membranes of target cells, leading to cell lysis and death.

Question 94

Define:

Cell Metabolism

Answer 94

The set of life-sustaining chemical reactions in cells, which can be increased by fever to accelerate immune responses and recovery.

Question 95

Define:

Fever

Answer 95

An increase in body temperature triggered by pyrogens, which can inhibit pathogen growth and speed up immune cell activity.

Question 96

Define:

Third line of defence

Answer 96

Also known as adaptive defences, activated when innate defenses are breached, targeting specific pathogens and abnormal cells with a systemic immune response.

Question 97

Define:

Antigen

Answer 97

A foreign substance that activates the body’s adaptive defenses, leading to an immune response. Antigens are often large, complex molecules such as proteins or polysaccharides.

Question 98

Define:

Antigen-Presenting Cells

Answer 98

Cells, such as macrophages and dendritic cells, that capture and display antigens on their surface to activate T cells in the adaptive immune response.

Question 99

Define:

Immunocompetence

Answer 99

The ability of T and B cells to recognize and bind to a specific antigen due to unique surface receptors, enabling them to mount an immune response.

Question 100

Define:

Immunological Memory

Answer 100

The adaptive immune system’s ability to remember previously encountered antigens, leading to a faster and stronger immune response upon re-exposure.

Question 101

Define:

Primary Immune Response

Answer 101

The initial immune response generated when an antigen enters the body for the first time, leading to the production of memory T and B cells.

Question 102

Define:

Secondary Immune Response

Answer 102

A stronger, quicker immune response triggered by the re-entry of a previously encountered antigen, due to the presence of memory T and B cells.

Question 103

Define:

Self-Tolerance

Answer 103

The ability of T and B cells to distinguish between self-antigens (normal body molecules) and foreign antigens, preventing attacks on the body’s own tissues.

Question 104

Define:

T Cells

Answer 104

A type of lymphocyte involved in the immune response, with various subtypes, including cytotoxic T cells and helper T cells, that play distinct roles in cellular immunity.

Question 105

Define:

B Cells

Answer 105

A type of lymphocyte that mediates the humoral immune response by producing antibodies specific to antigens.

Question 106

Define:

Helper T Cells

Answer 106

A subtype of T cells that activates both cytotoxic T cells and B cells, initiating the cellular and humoral immune responses.

Question 107

Define:

Cytotoxic T Cells

Answer 107

A subtype of T cells that target and destroy infected or abnormal cells, such as cancer cells or virus-infected cells, by inducing apoptosis.

Question 108

Define:

Cellular Immune Response

Answer 108

The immune response mediated by cytotoxic T cells, which involves the direct destruction of infected or abnormal cells.

Question 109

Define:

Humoral Immune Response

Answer 109

The immune response mediated by B cells, characterized by the production of antibodies that target antigens in body fluids.

Question 110

Define:

Antigen-Presenting Cells

Answer 110

Cells that capture and display antigens to T cells, initiating the activation of helper T cells in the adaptive immune response.

Question 111

Define:

Cytokines

Answer 111

Signaling proteins secreted by immune cells, such as helper T cells, that play a crucial role in activating other immune cells, including cytotoxic T cells and B cells.

Question 112

Define:

Plasma Cells

Answer 112

Specialized B cells that produce and secrete large quantities of antibodies during the humoral immune response.

Question 113

Define:

Antibodies

Answer 113

Proteins produced by plasma cells that specifically bind to antigens, forming complexes that tag the antigen for destruction by other immune cells or systems.

Question 114

Define:

Complement System

Answer 114

A group of proteins in the blood that, when activated by antibodies bound to antigens, can lyse cellular antigens or opsonize non-cellular antigens for phagocytosis.

Question 115

Define:

Phagocytosis

Answer 115

The process by which immune cells, such as macrophages, engulf and digest antigens or pathogens.

Question 116

Define:

Immunoglobulins (Ig)

Answer 116

A family of proteins that function as antibodies, classified into different types (IgM, IgG, IgA, IgD, IgE), each with specific roles and locations in the body.

Question 117

Define:

Memory T Cells

Answer 117

Long-lived T cells that persist after an initial immune response, ready to quickly respond to a previously encountered antigen during a secondary immune response.

Question 118

Define:

Memory B Cells

Answer 118

Long-lived B cells that persist after an initial immune response, quickly dividing to produce plasma cells and antibodies upon re-exposure to the same antigen.

Question 119

Define:

IgM

Answer 119

The first class of antibodies produced during a primary immune response, which gradually increases in blood levels before being followed by IgG.

Question 120

Define:

IgG

Answer 120

A class of antibodies that rapidly increases in blood levels during a secondary immune response, indicating the body’s enhanced ability to fight the antigen.

Question 121

Define:

Vaccine

Answer 121

A biological preparation that stimulates a primary immune response by exposing the body to an inactive or attenuated antigen, creating memory cells that provide immunity.

Question 122

Define:

Edward Jenner

Answer 122

The English doctor who invented the first vaccine by using cowpox to protect against smallpox, laying the foundation for modern vaccination practices.

Question 123

Define:

Smallpox

Answer 123

A highly contagious and deadly disease eradicated through vaccination, with the smallpox vaccine being the first successful vaccine ever developed.

Question 124

Define:

IgE

Answer 124

A class of antibodies involved in allergic reactions and responses to parasitic infections. IgE binds to allergens and triggers the release of histamines from mast cells and basophils.

Question 125

Define:

IgA

Answer 125

A class of antibodies found primarily in mucous membranes, saliva, tears, and breast milk, playing a crucial role in mucosal immunity by preventing pathogens from entering the body.

Question 126

Define:

IgD

Answer 126

A class of antibodies that is present on the surface of immature B cells and plays a role in initiating B cell activation during the immune response.

Question 127

Define:

Immunodeficiency Diseases

Answer 127

Conditions where the immune system’s defenses are absent or not functioning properly, leading to an inability to generate an effective immune response.

Question 128

Define:

Severe Combined Immunodeficiency (SCID)

Answer 128

A group of genetic disorders characterized by the absence of functional T and B cells, resulting in a severely compromised immune system and a high risk of fatal infections without intervention.

Question 129

Define:

Acquired Immunodeficiency Syndrome (AIDS)

Answer 129

A disease caused by the human immunodeficiency virus (HIV) that destroys helper T cells, severely weakening the immune system and making the body susceptible to infections and cancers.

Question 130

Define:

Human Immunodeficiency Virus (HIV)

Answer 130

The virus that causes AIDS by infecting and destroying helper T cells, leading to a severely compromised immune system.

Question 131

Define:

Autoimmune Diseases

Answer 131

Diseases in which the immune system mistakenly attacks the body’s own cells and tissues, failing to distinguish between self and non-self antigens.

Question 132

Define:

Rheumatoid Arthritis

Answer 132

An autoimmune disease where the immune system attacks the joints, causing inflammation, pain, and eventual joint damage.

Question 133

Define:

Type 1 Diabetes

Answer 133

An autoimmune disease where the immune system attacks the insulin-producing cells in the pancreas, leading to a lack of insulin and high blood sugar levels.

Question 134

Define:

Multiple Sclerosis

Answer 134

An autoimmune disease where the immune system attacks the protective covering of nerve fibers, disrupting communication between the brain and the rest of the body.

Question 135

Define:

Hypersensitivities (Allergic Reactions)

Define:

Answer 135

Excessive immune responses to harmless antigens, known as allergens, leading to symptoms like itching, swelling, and breathing difficulties.

Question 136

Define:

Allergen

Answer 136

A substance that causes an allergic reaction in susceptible individuals, such as dust, pollen, bee venom, or certain foods.

Question 137

Define:

Mast Cells

Answer 137

Immune cells found in tissues that release histamine and other chemicals during an allergic reaction, contributing to symptoms like swelling and bronchoconstriction.

Question 138

Define: Define:

Basophils

Answer 138

A type of white blood cell that releases histamine during allergic reactions, contributing to symptoms like swelling and bronchoconstriction.

Question 139

Define:

Histamine

Answer 139

A chemical released by mast cells and basophils during an allergic reaction that causes symptoms like bronchoconstriction, increased mucus secretion, and blood vessel dilation.

Question 140

Define:

Anaphylactic Shock

Answer 140

A severe, life-threatening systemic allergic reaction that causes widespread bronchoconstriction, decreased blood pressure, and potential circulatory collapse. It requires immediate treatment with adrenaline.

Question 141

Adrenaline (Epinephrine)

Answer 141

A hormone and medication used to treat anaphylactic shock by rapidly dilating the bronchioles and constricting blood vessels, helping to restore blood pressure and maintain blood flow.

Question 142

What is …

The network of cells, tissues, and organs that work together to protect the body from harmful materials and diseases, including abnormal body cells that could lead to cancers.

Answer 142

Lymphoid System

Question 143

What is …

A complex system of biological structures and processes that protect the body from pathogens and other harmful materials through cell-to-cell interactions and immune responses.

Answer 143

Immune System

Question 144

What is …

Any microorganism, such as a virus, bacteria, fungus, or worm, that can cause disease within the host body.

Answer 144

Pathogen

Question 145

What is …

A natural immune response characterized by redness, heat, swelling, and pain, often occurring in response to infection or injury.

Answer 145

Inflammation

Question 146

What is …

An elevated body temperature that is a common immune response to infection, helping the body fight off pathogens.

Answer 146

Fever

Question 147

What is …

The medical procedure of transferring cells, tissues, or organs from one body to another, which requires careful management of immune responses to prevent rejection.

Answer 147

Transplants

Question 148

What is …

Conditions where the immune system is weakened or not functioning properly, making the body more susceptible to infections and diseases.

Answer 148

Immunodeficiency Diseases

Question 149

What is …

Diseases in which the immune system mistakenly attacks the body’s own cells, such as rheumatoid arthritis and type 1 diabetes.

Answer 149

Autoimmune Diseases

Question 150

What is …

Pathogens that infect and replicate within body cells, often leading to the destruction of the infected cells.

Answer 150

Viruses

Question 151

What is …

Parasitic organisms that live in the intestines and cause various diseases in their host.

Answer 151

Worms

Question 152

What is …

Microorganisms that multiply in body fluids and produce toxins, leading to damage of cells, tissues, and organs.

Answer 152

Bacteria

Question 153

What is …

The combined components of the lymphatic system, lymphoid organs and tissues, white blood cells, and cytokines that work together to protect the body from harmful materials and diseases.

Answer 153

Lymphoid System

Question 154

What is …

A network of lymphatic capillaries, vessels, lymph nodes, and the fluid called lymph, responsible for circulating body fluids, removing foreign materials, and transporting white blood cells to infection sites.

Answer 154

Lymphatic System

Question 155

What is …

Excess interstitial fluid collected by lymphatic capillaries, which is then circulated through the lymphatic system to maintain blood volume and pressure, and to remove foreign materials.

Answer 155

Lymph

Question 156

What is …

Fluid that surrounds body cells, produced by the balance of hydrostatic and colloid osmotic pressures in capillaries, with excess being collected by lymphatic capillaries as lymph.

Answer 156

Interstitial Fluid

Question 157

What is …

The pressure exerted by fluid within blood vessels, delivering interstitial fluid to body tissues.

Answer 157

Hydrostatic Pressure

Question 158

What is …

The pressure exerted by proteins in blood plasma, which pulls interstitial fluid back into the blood vessels.

Answer 158

Colloid Osmotic Pressure

Question 159

What is …

Tiny, thin-walled vessels located between body cells that collect interstitial fluid, white blood cells, and foreign materials, allowing them to enter the lymphatic system.

Answer 159

Lymphatic Capillaries

Question 160

What is …

Small, bean-shaped structures located along lymphatic vessels that filter lymph, trapping and removing foreign materials, and facilitating an immune response.

Answer 160

Lymph Nodes

Question 161

What is …

A condition where excess interstitial fluid accumulates in body tissues due to an impaired lymphatic system, leading to swelling and increased risk of infection.

Answer 161

Lymphedema

Question 162

What is …

A tropical disease caused by parasitic worms blocking lymphatic vessels, leading to severe swelling, particularly in the lower limbs and scrotum.

Answer 162

Elephantiasis

Question 163

What is …

Cells that are part of the immune system, responsible for defending the body against foreign materials, including bacteria, viruses, parasites, and cancerous cells.

Answer 163

White Blood Cells (WBCs)

Question 164

What is …

Communication molecules produced by white blood cells that recruit or activate specific white blood cells to respond to infections or destroy foreign materials.

Answer 164

Cytokines

Question 165

What is …

A type of cytokine involved in the immune response, particularly in inhibiting viral replication within host cells.

Answer 165

Interferons

Question 166

What is …

A cytokine that plays a key role in the regulation of immune and inflammatory responses to infections or injuries.

Answer 166

Interleukin-1 (IL-1)

Question 167

What is …

A cytokine that stimulates the growth and activity of white blood cells, particularly T cells, as part of the immune response.

Answer 167

Interleukin-2 (IL-2)

Question 168

What is …

Organs, such as red bone marrow and the thymus, where white blood cells are produced.

Answer 168

Primary Lymphoid Organs

Question 169

What is …

Organs and tissues, including lymph nodes, spleen, tonsils, appendix, and those lining the gastrointestinal and urinary tracts, where foreign materials are trapped, destroyed, and immune responses are activated.

Answer 169

Secondary Lymphoid Organs and Tissues

Question 170

What is …

The immune system’s initial defense mechanisms that protect against any type of foreign material before it can enter or spread throughout the body.

Answer 170

Innate Defenses (Non-Specific Defenses)

Question 171

What is …

The immune system’s targeted response to specific pathogens that have spread and invaded the body, involving the generation of an immune response.

Answer 171

Adaptive Defenses (Specific Defenses)

Question 172

What is …

The body’s first line of defense against pathogens, including physical and chemical barriers like skin and mucous membranes.

Answer 172

Surface Barriers

Question 173

What is …

Proteins found within the body that play a role in the immune system’s internal defenses, helping to identify and neutralize pathogens.

Answer 173

Protective Proteins

Question 174

What is …

The body’s third line of defense, where the immune system generates a specific response to eliminate invading pathogens.

Answer 174

Immune Response

Question 175

What is …

Structural defenses like the skin and mucous membranes that create a barrier to block foreign materials from penetrating the body.

Answer 175

Physical Barriers

Question 176

What is …

Thin layers of tissue lining body tracts (e.g., gastrointestinal, respiratory, urinary, and reproductive tracts) that form a barrier to prevent the entry of foreign materials.

Answer 176

Mucous Membranes

Question 177

What is …

Cells forming the outer layer of the skin and mucous membranes, providing a protective barrier against foreign materials.

Answer 177

Epithelial Cells

Question 178

What is …

Structures like hair and cilia that assist in trapping and removing foreign materials from the body’s surfaces.

Answer 178

Accessory Structures

Question 179

What is …

A mechanism in the respiratory tract where cilia move mucus and trapped foreign materials away from the lungs toward the throat to be expelled or swallowed.

Answer 179

Mucociliary Escalator

Question 180

What is …

Beneficial bacteria that colonize various body surfaces and cavities, inhibiting the growth of pathogens by competing for nutrients and space.

Answer 180

Normal Flora

Question 181

What is …

Body secretions such as sweat, saliva, tears, sebum, mucus, and gastric juice that cleanse and protect body surfaces by destroying or trapping foreign materials.

Answer 181

Chemical Barriers

Question 182

What is …

An enzyme found in sweat, saliva, and tears that specifically targets and destroys bacteria.

Answer 182

Lysozyme

Question 183

What is …

An oily, acidic secretion produced by sebaceous glands that covers the skin, inhibiting the growth of pathogens and being toxic to some bacteria.

Answer 183

Sebum

Question 184

What is …

A sticky, viscous fluid that lines the gastrointestinal and respiratory tracts, trapping foreign materials that enter internal passageways.

Answer 184

Mucus

Question 185

What is …

A digestive fluid in the stomach containing hydrochloric acid and the enzyme pepsin, which destroys foreign materials that enter the stomach.

Answer 185

Gastric Juice

Question 186

What is …

The body’s initial protection against foreign materials, consisting of physical and chemical barriers that prevent entry.

Answer 186

First Line of Defense

Question 187

What is …

Internal defense mechanisms, including white blood cells, protective proteins, and inflammatory responses, that activate when the first line of defense is breached.

Answer 187

Second Line of Defense

Question 188

What is …

Immune cells, such as macrophages, neutrophils, and natural killer cells, that play key roles in defending the body against invaders.

Answer 188

White Blood Cells

Question 189

What is …

Phagocytic white blood cells that engulf and digest foreign materials, including bacteria, viruses, and cancer cells.

Answer 189

Macrophages

Question 190

What is …

Phagocytic white blood cells that target and consume bacteria and other foreign materials, often indicating bacterial infection when elevated.

Answer 190

Neutrophils

Question 191

What is …

A type of white blood cell that detects and destroys virus-infected and cancerous cells by inducing apoptosis through the release of perforins and granzymes.

Answer 191

Natural Killer (NK) Cells

Question 192

What is …

Proteins released by NK cells that create pores in the target cell membrane, allowing destructive enzymes to enter.

Answer 192

Perforins

Question 193

What is …

Enzymes released by NK cells that induce apoptosis, causing the target cell to self-destruct.

Answer 193

Granzymes

Question 194

What is …

Cytokines produced by white blood cells and virus-infected cells that interfere with viral replication and activate macrophages and NK cells.

Answer 194

Interferons

Question 195

What is …

A group of plasma proteins that enhance immune responses by promoting phagocytosis, recruiting immune cells, and directly destroying pathogens through the formation of membrane attack complexes.

Answer 195

Complement System

Question 196

What is …

A process where complement proteins coat foreign materials, making them easier for macrophages and neutrophils to identify and consume.

Answer 196

Opsonization

Question 197

What is …

A reaction to tissue damage characterized by heat, redness, swelling, pain, and loss of function, which helps localize and eliminate foreign materials and repair tissues.

Answer 197

Inflammatory Response

Question 198

What is …

A chemical released during inflammation that causes blood vessels to dilate and become more permeable, facilitating immune cell movement to the site of injury.

Answer 198

Histamine

Question 199

What is …

Chemicals released during inflammation that contribute to pain and swelling by increasing blood vessel permeability and amplifying the inflammatory response.

Answer 199

Prostaglandins

Question 200

What is …

Substances, including interleukin-1 and bacterial toxins, that induce fever by resetting the body’s hypothalamic thermostat to a higher temperature.

Answer 200

Pyrogens

Question 201

What is …

A process of programmed cell death induced by immune cells to eliminate virus-infected or cancerous cells.

Answer 201

Apoptosis

Question 202

What is …

A structure formed by complement proteins that creates holes in the membranes of target cells, leading to cell lysis and death.

Answer 202

Membrane Attack Complex

Question 203

What is …

The set of life-sustaining chemical reactions in cells, which can be increased by fever to accelerate immune responses and recovery.

Answer 203

Cell Metabolism

Question 204

What is …

An increase in body temperature triggered by pyrogens, which can inhibit pathogen growth and speed up immune cell activity.

Answer 204

Fever

Question 205

What is …

Also known as adaptive defences, activated when innate defenses are breached, targeting specific pathogens and abnormal cells with a systemic immune response.

Answer 205

Third line of defence

Question 206

What is …

A foreign substance that activates the body’s adaptive defenses, leading to an immune response. Antigens are often large, complex molecules such as proteins or polysaccharides.

Answer 206

Antigen

Question 207

What is …

Cells, such as macrophages and dendritic cells, that capture and display antigens on their surface to activate T cells in the adaptive immune response.

Answer 207

Antigen-Presenting Cells

Question 208

What is …

The ability of T and B cells to recognize and bind to a specific antigen due to unique surface receptors, enabling them to mount an immune response.

Answer 208

Immunocompetence

Question 209

What is …

The adaptive immune system’s ability to remember previously encountered antigens, leading to a faster and stronger immune response upon re-exposure.

Answer 209

Immunological Memory

Question 210

What is …

The initial immune response generated when an antigen enters the body for the first time, leading to the production of memory T and B cells.

Answer 210

Primary Immune Response

Question 211

What is …

A stronger, quicker immune response triggered by the re-entry of a previously encountered antigen, due to the presence of memory T and B cells.

Answer 211

Secondary Immune Response

Question 212

What is …

The ability of T and B cells to distinguish between self-antigens (normal body molecules) and foreign antigens, preventing attacks on the body’s own tissues.

Answer 212

Self-Tolerance

Question 213

What is …

A type of lymphocyte involved in the immune response, with various subtypes, including cytotoxic T cells and helper T cells, that play distinct roles in cellular immunity.

Answer 213

T Cells

Question 214

What is …

A type of lymphocyte that mediates the humoral immune response by producing antibodies specific to antigens.

Answer 214

B Cells

Question 215

What is …

A subtype of T cells that activates both cytotoxic T cells and B cells, initiating the cellular and humoral immune responses.

Answer 215

Helper T Cells

Question 216

What is …

A subtype of T cells that target and destroy infected or abnormal cells, such as cancer cells or virus-infected cells, by inducing apoptosis.

Answer 216

Cytotoxic T Cells

Question 217

What is …

The immune response mediated by cytotoxic T cells, which involves the direct destruction of infected or abnormal cells.

Answer 217

Cellular Immune Response

Question 218

What is …

The immune response mediated by B cells, characterized by the production of antibodies that target antigens in body fluids.

Answer 218

Humoral Immune Response

Question 219

What is …

Cells that capture and display antigens to T cells, initiating the activation of helper T cells in the adaptive immune response.

Answer 219

Antigen-Presenting Cells

Question 220

What is …

Signaling proteins secreted by immune cells, such as helper T cells, that play a crucial role in activating other immune cells, including cytotoxic T cells and B cells.

Answer 220

Cytokines

Question 221

What is …

Specialized B cells that produce and secrete large quantities of antibodies during the humoral immune response.

Answer 221

Plasma Cells

Question 222

What is …

Proteins produced by plasma cells that specifically bind to antigens, forming complexes that tag the antigen for destruction by other immune cells or systems.

Answer 222

Antibodies

Question 223

What is …

A group of proteins in the blood that, when activated by antibodies bound to antigens, can lyse cellular antigens or opsonize non-cellular antigens for phagocytosis.

Answer 223

Complement System

Question 224

What is …

The process by which immune cells, such as macrophages, engulf and digest antigens or pathogens.

Answer 224

Phagocytosis

Question 225

What is …

A family of proteins that function as antibodies, classified into different types (IgM, IgG, IgA, IgD, IgE), each with specific roles and locations in the body.

Answer 225

Immunoglobulins (Ig)

Question 226

What is …

Long-lived T cells that persist after an initial immune response, ready to quickly respond to a previously encountered antigen during a secondary immune response.

Answer 226

Memory T Cells

Question 227

What is …

Long-lived B cells that persist after an initial immune response, quickly dividing to produce plasma cells and antibodies upon re-exposure to the same antigen.

Answer 227

Memory B Cells

Question 228

What is …

The first class of antibodies produced during a primary immune response, which gradually increases in blood levels before being followed by IgG.

Answer 228

IgM

Question 229

What is …

A class of antibodies that rapidly increases in blood levels during a secondary immune response, indicating the body’s enhanced ability to fight the antigen.

Answer 229

IgG

Question 230

What is …

A biological preparation that stimulates a primary immune response by exposing the body to an inactive or attenuated antigen, creating memory cells that provide immunity.

Answer 230

Vaccine

Question 231

What is …

The English doctor who invented the first vaccine by using cowpox to protect against smallpox, laying the foundation for modern vaccination practices.

Answer 231

Edward Jenner

Question 232

What is …

A highly contagious and deadly disease eradicated through vaccination, with the smallpox vaccine being the first successful vaccine ever developed.

Answer 232

Smallpox

Question 233

What is …

A class of antibodies involved in allergic reactions and responses to parasitic infections. IgE binds to allergens and triggers the release of histamines from mast cells and basophils.

Answer 233

IgE

Question 234

What is …

A class of antibodies found primarily in mucous membranes, saliva, tears, and breast milk, playing a crucial role in mucosal immunity by preventing pathogens from entering the body.

Answer 234

IgA

Question 235

What is …

A class of antibodies that is present on the surface of immature B cells and plays a role in initiating B cell activation during the immune response.

Answer 235

IgD

Question 236

What is …

Conditions where the immune system’s defenses are absent or not functioning properly, leading to an inability to generate an effective immune response.

Answer 236

Immunodeficiency Diseases

Question 237

What is …

A group of genetic disorders characterized by the absence of functional T and B cells, resulting in a severely compromised immune system and a high risk of fatal infections without intervention.

Answer 237

Severe Combined Immunodeficiency (SCID)

Question 238

What is …

A disease caused by the human immunodeficiency virus (HIV) that destroys helper T cells, severely weakening the immune system and making the body susceptible to infections and cancers.

Answer 238

Acquired Immunodeficiency Syndrome (AIDS)

Question 239

What is …

The virus that causes AIDS by infecting and destroying helper T cells, leading to a severely compromised immune system.

Answer 239

Human Immunodeficiency Virus (HIV)

Question 240

What is …

Diseases in which the immune system mistakenly attacks the body’s own cells and tissues, failing to distinguish between self and non-self antigens.

Answer 240

Autoimmune Diseases

Question 241

What is …

An autoimmune disease where the immune system attacks the joints, causing inflammation, pain, and eventual joint damage.

Answer 241

Rheumatoid Arthritis

Question 242

What is …

An autoimmune disease where the immune system attacks the insulin-producing cells in the pancreas, leading to a lack of insulin and high blood sugar levels.

Answer 242

Type 1 Diabetes

Question 243

What is …

An autoimmune disease where the immune system attacks the protective covering of nerve fibers, disrupting communication between the brain and the rest of the body.

Answer 243

Multiple Sclerosis

Question 244

What is …

Excessive immune responses to harmless antigens, known as allergens, leading to symptoms like itching, swelling, and breathing difficulties.

Answer 244

Hypersensitivities (Allergic Reactions)

Question 245

What is …

A substance that causes an allergic reaction in susceptible individuals, such as dust, pollen, bee venom, or certain foods.

Answer 245

Allergen

Question 246

What is …

Immune cells found in tissues that release histamine and other chemicals during an allergic reaction, contributing to symptoms like swelling and bronchoconstriction.

Answer 246

Mast Cells

Question 247

What is …

A type of white blood cell that releases histamine during allergic reactions, contributing to symptoms like swelling and bronchoconstriction.

Answer 247

Basophils

Question 248

What is …

A chemical released by mast cells and basophils during an allergic reaction that causes symptoms like bronchoconstriction, increased mucus secretion, and blood vessel dilation.

Answer 248

Histamine

Question 249

What is …

A severe, life-threatening systemic allergic reaction that causes widespread bronchoconstriction, decreased blood pressure, and potential circulatory collapse. It requires immediate treatment with adrenaline.

Answer 249

Anaphylactic Shock

Question 250

What is …

A hormone and medication used to treat anaphylactic shock by rapidly dilating the bronchioles and constricting blood vessels, helping to restore blood pressure and maintain blood flow.

Answer 250

Adrenaline (Epinephrine)

Question 251

How do the lymphoid and immune systems work together?

Answer 251

They work together to protect the body from harmful materials, such as pathogens and diseases.

Question 252

How do viruses attack the body?

Answer 252

They infect body cells, replicate within those cells, and often destroy the cells they infect.

Question 253

Where do worms typically reside in the body?

Answer 253

In the small or large intestines.

Question 254

How do bacteria cause harm to the body?

Answer 254

They multiply in body fluids and secrete toxins that damage cells, tissues, and entire organ systems.

Question 255

How do we remain relatively healthy despite constant exposure to pathogens?

Answer 255

Our health relies on the components of the lymphoid system working together to protect us from harmful materials.

Question 256

What are the components of the lymphoid system?

Answer 256

The lymphatic system, lymphoid organs and tissues, white blood cells, and cytokines.

Question 257

What does the lymphatic system consist of?

Answer 257

Lymphatic capillaries, lymphatic vessels, lymph nodes, and lymph.

Question 258

What is the primary function of the lymphatic system?

Answer 258

To circulate body fluids, remove foreign materials, and transport white blood cells to infection sites.

Question 259

What is lymph?

Answer 259

Lymph is excess interstitial fluid that enters lymphatic capillaries and becomes lymph.

Question 260

What causes the remaining 3 liters of interstitial fluid to become lymph?

Answer 260

It enters lymphatic capillaries due to the imbalance between hydrostatic and colloid osmotic pressures.

Question 261

What is the function of lymphatic capillaries?

Answer 261

They allow interstitial fluid, white blood cells, pathogens, and foreign materials to enter while preventing their return to body tissues.

Question 262

How does lymph flow through the body?

Answer 262

It flows from lymphatic capillaries through lymph vessels and lymph nodes, eventually returning to the venous circulation near the heart.

Question 263

What happens if the lymphatic system cannot return the 3 liters of interstitial fluid to the blood?

Answer 263

It leads to lymphedema, where fluid accumulates in body tissues.

Question 264

What are common causes of lymphedema?

Answer 264

Removal of lymphatic vessels during surgery or blockage by tumors or pathogens.

Question 265

What is elephantiasis and what causes it?

Answer 265

Elephantiasis is a tropical disease caused by a parasitic worm that blocks lymphatic vessels, especially in the lower limbs and scrotum.

Question 266

What is the role of lymph nodes?

Answer 266

What is the role of lymph nodes?

Question 267

What happens when a large number of pathogens are trapped in a lymph node?

Answer 267

The lymph node may become swollen and sore.

Question 268

What are primary lymphoid organs?

Answer 268

The red bone marrow and the thymus.

Question 269

What is the function of primary lymphoid organs?

Answer 269

They are responsible for producing white blood cells.

Question 270

What are secondary lymphoid organs and tissues?

Answer 270

Lymph nodes, spleen, tonsils, appendix, and the tissues lining the gastrointestinal and urinary tracts.

Question 271

What is the role of secondary lymphoid organs and tissues?

Answer 271

They trap and destroy foreign materials and activate immune responses.

Question 272

What types of white blood cells are involved in defending the body?

Answer 272

Neutrophils, macrophages, mast cells, basophils, eosinophils, and lymphocytes.

Question 273

What are cytokines?

Answer 273

Communication molecules that recruit or activate white blood cells to respond to infection.

Question 274

What are the two main types of immune defenses?

Answer 274

Innate (non-specific) defenses and adaptive (specific) defenses.

Question 275

How do innate defenses protect the body?

Answer 275

They destroy any type of foreign material before it can enter or spread throughout the body.

Question 276

How do adaptive defenses protect the body?

Answer 276

They target specific enemies that are spreading and invading the body.

Question 277

What are the three lines of defense in the immune system?

Answer 277

Body’s surface barriers.
Internal defenses like white blood cells and protective proteins.
Immune response generation.

Question 278

Why are the first and second lines of defense called innate defenses?

Answer 278

Because they are present and active from birth and protect against any type of foreign material.

Question 279

How do the first and second lines of defense respond to foreign materials?

Answer 279

They respond within minutes to prevent foreign materials from entering the body and stop those that do enter from spreading.

Question 280

What are the functions of the body’s surface barriers in the first line of defense?

Answer 280

To prevent foreign materials from entering, trap and remove foreign materials, expel foreign materials, and secrete destructive chemicals and enzymes.

Question 281

What are some examples of physical barriers in the first line of defense?

Answer 281

The skin and mucous membranes lining the gastrointestinal, respiratory, urinary, and reproductive tracts.

Question 282

How do the accessory structures like hairs and cilia contribute to defense?

Answer 282

Hairs trap foreign materials, and cilia sweep materials away from respiratory surfaces towards the throat.

Question 283

What is the role of normal flora in the body’s defense?

Answer 283

Normal flora inhibit pathogen survival by consuming nutrients and competing for space and attachment sites on body cells.

Question 284

Where do normal flora commonly colonize?

Answer 284

The skin, upper respiratory tract, digestive tract, urinary tract, and reproductive tract.

Question 285

What are some examples of chemical barriers in the body’s defense?

Answer 285

Sweat, saliva, tears, sebum, mucus, and gastric juice.

Question 286

How do sweat, saliva, and tears contribute to defense?

Answer 286

They cleanse body surfaces and contain the enzyme lysozyme, which destroys bacteria.

Question 287

What is the function of sebum?

Answer 287

To cover the skin surface with an oily, acidic secretion that inhibits pathogen growth and is toxic to some bacteria.

Question 288

How does mucus contribute to the body’s defense?

Answer 288

It traps foreign materials that enter internal passageways such as the gastrointestinal and respiratory tracts.

Question 289

What are the components of gastric juice, and how do they aid in defense?

Answer 289

Hydrochloric acid and the enzyme pepsin destroy foreign materials in the stomach.

Question 290

What happens when the body’s first line of defense is breached?

Answer 290

The body’s internal defense mechanisms activate to prevent the invader from spreading throughout the body.

Question 291

What types of cells are involved in the second line of defense?

Answer 291

Macrophages, neutrophils, and natural killer (NK) cells.

Question 292

What do macrophages and neutrophils do?

Answer 292

They are phagocytic cells that engulf and destroy foreign materials, including bacteria, toxins, viruses, and cancerous cells.

Question 293

How do macrophages and neutrophils destroy invaders?

Answer 293

They migrate to the site of invasion, adhere to the invader, engulf it, and digest it using lysosomal enzymes. If the invader is too large, they can release digestive enzymes into the extracellular fluid.

Question 294

What indicates a bacterial infection in terms of white blood cells?

Answer 294

A high neutrophil count in the blood usually indicates a bacterial infection.

Question 295

What is the role of natural killer (NK) cells?

Answer 295

They monitor the blood and lymph to detect and destroy virus-infected and cancerous cells before they spread.

Question 296

How do NK cells destroy target cells?

Answer 296

NK cells release perforins to create pores in the target cell membrane and granzymes to induce apoptosis.

Question 297

What are interferons and how do they function?

Answer 297

Interferons are cytokines that interfere with viral replication by prompting nearby cells to produce antiviral proteins. They can also activate macrophages and NK cells.

Question 298

What is a symptom of interferons working in response to a viral infection?

Answer 298

Aching muscles and fever.

Question 299

What is the complement system?

Answer 299

A group of approximately 20 plasma proteins that monitor body fluids and tissues for foreign materials and help eliminate invaders.

Question 300

How do complement proteins enhance the immune response?

Answer 300

They recruit macrophages and neutrophils to the site of invasion, enhance phagocytosis through opsonization, and can directly destroy invaders.

Question 301

What is opsonization?

Answer 301

A process where complement proteins make foreign materials easier for macrophages and neutrophils to identify and consume.

Question 302

What happens during an inflammatory response?

Answer 302

It is characterized by heat, redness, swelling, pain, and loss of function, and it localizes and contains foreign materials, disposes of damaged cells, and sets the stage for repair.

Question 303

What triggers the inflammatory response?

Answer 303

Injured cells release inflammatory chemicals like histamine and prostaglandins, causing blood vessels to dilate and become more permeable.

Question 304

What are the effects of increased blood flow and capillary permeability during inflammation?

Answer 304

Increased blood flow makes the area red and warm, while increased permeability allows fluid and immune cells to enter the injured tissue, causing swelling and pain.

Question 305

How does fever contribute to the body’s defense?

Answer 305

Fever, induced by pyrogens, raises the body’s temperature, which can inhibit the growth of some pathogens and increase cell metabolism, accelerating recovery.

Question 306

What are pyrogens and what do they do?

Answer 306

Pyrogens are proteins that reset the body’s thermostat to a higher temperature, causing fever. They include interleukin-1, interferons, and some bacterial toxins.

Question 307

How does a fever affect cell metabolism?

Answer 307

For every 1°C increase in temperature, cell metabolism increases by 10%, which speeds up the activity of white blood cells and aids in recovery.

Question 308

What is the main purpose of the first and second lines of defense?

Answer 308

To immediately respond and protect the body from foreign materials and prevent them from spreading or invading.

Question 309

What happens when the body’s innate defenses fail?

Answer 309

The adaptive defenses are activated to eliminate the invader.

Question 310

How do adaptive defenses differ from innate defenses?

Answer 310

Adaptive defenses are acquired and develop throughout life, whereas innate defenses are present from birth.

Question 311

What is an antigen?

Answer 311

An antigen is a foreign substance that activates the body’s adaptive defenses.

Question 312

What are some examples of antigens?

Answer 312

Examples include proteins or polysaccharides on viruses or bacteria, bacterial toxins, pollen, egg white, and transplanted tissue proteins.

Question 313

Which cells are involved in the adaptive immune response?

Answer 313

T cells and B cells.

Question 314

What role do antigen-presenting cells play in the adaptive immune response?

Answer 314

They capture, engulf, and present antigens to T cells, activating them.

Question 315

How do antigen-presenting cells signal T cells?

Answer 315

By displaying antigens or antigen fragments on their cell surface.

Question 316

What is immunocompetence?

Answer 316

The ability of T and B cells to recognize and bind to one specific antigen.

Question 317

How do T cells and B cells recognize antigens?

Answer 317

T cells use T cell receptors, and B cells use antibody receptors.

Question 318

What is self-tolerance?

Answer 318

The ability of T and B cells to be unresponsive to self-antigens or molecules normally found in the body.

Question 319

Where do T cells and B cells mature?

Answer 319

B cells mature in the bone marrow, and T cells mature in the thymus.

Question 320

What happens if T and B cells fail to develop self-tolerance?

Answer 320

They may attack normal body cells, potentially leading to autoimmune diseases.

Question 321

What is immunological memory?

Answer 321

The ability of T and B cells to remember and mount a stronger response to previously encountered antigens.

Question 322

What is the primary immune response?

Answer 322

The initial response to a new antigen, which produces a large number of memory T and B cells.

Question 323

What is the secondary immune response?

Answer 323

A stronger, longer-lasting response to an antigen that the body has encountered before, thanks to memory T and B cells.

Question 324

How is an immune response triggered?

Answer 324

An immune response is triggered when an antigen breaches the body’s first and second lines of defense and reaches a lymph node.

Question 325

What are the two main types of immune responses?

Answer 325

The two main types are the cellular immune response and the humoral immune response.

Question 326

Which cells mediate the cellular immune response?

Answer 326

Cytotoxic T cells mediate the cellular immune response.

Question 327

Which cells mediate the humoral immune response?

Answer 327

B cells mediate the humoral immune response.

Question 328

What is the role of helper T cells in the immune response?

Answer 328

Helper T cells activate both cytotoxic T cells and B cells by secreting cytokines.

Question 329

How does a helper T cell become activated?

Answer 329

A helper T cell becomes activated when an antigen-presenting cell displays an antigen on its surface, which the helper T cell recognizes and binds to.

Question 330

What do effector helper T cells do?

Answer 330

Effector helper T cells secrete cytokines to activate cytotoxic T cells and B cells.

Question 331

What is the function of cytotoxic T cells?

Answer 331

Cytotoxic T cells destroy cellular antigens such as cancer cells, foreign cells, and infected body cells.

Question 332

How do cytotoxic T cells destroy their target cells?

Answer 332

Cytotoxic T cells release perforins to create pores in the target cell membrane and granzymes to induce apoptosis.

Question 333

What is the role of B cells in the immune response?

Answer 333

B cells produce antibodies that target both cellular and non-cellular antigens.

Question 334

What happens when a B cell is activated?

Answer 334

Activated B cells proliferate and differentiate into memory B cells and plasma cells, which secrete antibodies.

Question 335

How do antibodies eliminate antigens?

Answer 335

Antibodies bind to antigens, forming complexes that are inactivated and tagged for destruction by macrophages, neutrophils, or complement proteins.

Question 336

What is the complement system’s role in the immune response?

Answer 336

The complement system helps destroy antigens by forming membrane attack complexes or enhancing phagocytosis.

Question 337

What are the five classes of antibodies?

Answer 337

IgM, IgG, IgA, IgD, and IgE.

Question 338

How do antibodies differ from one another?

Answer 338

Each antibody class has structural differences, serves different biological roles, and is found in different locations in the body.

Question 339

What is the difference between cellular and non-cellular antigens?

Answer 339

Cellular antigens include cells such as bacteria and cancer cells, while non-cellular antigens include substances like toxins and virus particles.

Question 340

What happens if an antibody binds to a cellular antigen?

Answer 340

The complement system forms a membrane attack complex that lyses the antigen.

Question 341

What happens if an antibody binds to a non-cellular antigen?

Answer 341

The complement system opsonizes the antigen, enhancing phagocytosis.

Question 342

What characterizes a primary immune response?

Answer 342

A primary immune response is typically small, slow, and involves a limited number of antigen-specific T and B cells.

Question 343

How long does it usually take for antibody levels to peak during a primary immune response?

Answer 343

It takes about eight to fourteen days for antibody levels to peak during a primary immune response.

Question 344

Why might symptoms of infection begin within the first few days of exposure?

Answer 344

Symptoms often begin within the first few days due to the lag phase of the primary immune response, which does not immediately prevent illness.

Question 345

Which antibody is always the first produced in a primary immune response?

Answer 345

IgM is always the first antibody produced when a new antigen enters the body.

Question 346

What happens to IgM and IgG levels during a primary immune response?

Answer 346

IgM levels increase first, followed by a rise in IgG levels, which then decline as antibodies and antigens are phagocytosed.

Question 347

What is the main function of a primary immune response?

Answer 347

The main function of a primary immune response is to produce thousands of antigen-specific memory T and B cells.

Question 348

How do memory T and B cells contribute to a secondary immune response?

Answer 348

Memory T and B cells mount a rapid and powerful secondary immune response if the same antigen re-enters the body.

Question 349

What is the primary difference between a primary and a secondary immune response?

Answer 349

A secondary immune response is faster and more robust, with high levels of IgG quickly appearing in the blood.

Question 350

How do vaccines use the concept of the secondary immune response?

Answer 350

Vaccines expose the body to an antigen for the first time to activate a primary immune response and generate long-lived memory T and B cells.

Question 351

Why do vaccines not cause illness?

Answer 351

Vaccines typically contain inactive or attenuated forms of antigens that cannot infect body cells.

Question 352

How many doses are generally required for maximum protection with the Hepatitis B vaccine?

Answer 352

It generally requires two to five doses of the Hepatitis B vaccine to achieve maximum protection.

Question 353

Who invented the first smallpox vaccine, and what was the basis of his discovery?

Answer 353

Edward Jenner invented the first smallpox vaccine based on the observation that people who had cowpox did not develop smallpox.

Question 354

What was the outcome of widespread smallpox vaccination?

Answer 354

The widespread use of the smallpox vaccine led to the official eradication of the disease.

Question 355

How does the immune response start?

Answer 355

The immune response begins when an antigen is captured and engulfed by an antigen-presenting cell, which then presents it to a helper T cell.

Question 356

What role do cytokines play in the immune response?

Answer 356

Cytokines, particularly interleukin-2, help activate antigen-specific cytotoxic T cells and B cells.

Question 357

How do B cells contribute to the humoral immune response?

Answer 357

B cells differentiate into plasma cells that secrete antibodies to inactivate and tag antigens for destruction.

Question 358

What is the role of cytotoxic T cells in the cellular immune response?

Answer 358

Cytotoxic T cells destroy cellular antigens by releasing perforins and granzymes.

Question 359

What does the immune response generate to protect against future infections?

Answer 359

The immune response generates thousands of long-lived memory helper T cells, B cells, and cytotoxic T cells.

Question 360

What can cause immunodeficiency diseases?

Answer 360

Immunodeficiency diseases can be caused by the body’s immune defenses being absent or not functioning properly, resulting in an ineffective immune response.

Question 361

What is severe combined immunodeficiency (SCID)?

Answer 361

SCID is a severe inherited immunodeficiency where individuals lack both T and B cells, making them unable to mount an effective immune response.

Question 362

How can individuals with SCID survive?

Answer 362

Individuals with SCID may survive by living in sterile environments or receiving bone marrow transplants to provide functional T and B cells.

Question 363

What virus causes acquired immunodeficiency syndrome (AIDS)?

Answer 363

AIDS is caused by the human immunodeficiency virus (HIV).

Question 364

How does HIV affect the immune system?

Answer 364

HIV infects and destroys helper T cells, severely compromising the immune system and impairing both cellular and humoral immune responses.

Question 365

What are common outcomes for patients with AIDS without treatment?

Answer 365

Without treatment, patients with AIDS typically survive 9 to 11 years, often dying from infections or cancers due to their weakened immune system.

Question 366

What is an autoimmune disease?

Answer 366

An autoimmune disease occurs when the body’s immune system mistakenly attacks normal cells and tissues.

Question 367

Give three examples of autoimmune diseases.

Answer 367

Rheumatoid arthritis, type 1 diabetes, and multiple sclerosis are examples of autoimmune diseases.

Question 368

What can lead to autoimmune diseases?

Answer 368

Autoimmune diseases can result from the failure of T and B cells to distinguish between self and non-self antigens, leading to the destruction of normal body cells or production of autoantibodies.

Question 369

What are hypersensitivities or allergic reactions?

Answer 369

Hypersensitivities, or allergic reactions, occur when the immune system overreacts to harmless antigens that most people tolerate without issue.

Question 370

What is an allergen?

Answer 370

An allergen is the substance that causes an allergic reaction, such as dust, pollen, bee venom, drugs, or certain foods.

Question 371

What type of antibodies mediate most allergic reactions?

Answer 371

Most allergic reactions are mediated by IgE antibodies.

Question 372

What happens during the first exposure to an allergen?

Answer 372

During the first exposure, plasma cells produce IgE antibodies, which bind to mast cells and basophils, but no symptoms typically occur.

Question 373

How do symptoms of an allergic reaction occur upon re-exposure to an allergen?

Answer 373

Upon re-exposure, the allergen binds to IgE antibodies, causing mast cells and basophils to release histamine, which leads to symptoms such as watery eyes, a runny nose, and breathing difficulties.

Question 374

What effects does histamine have during an allergic reaction?

Answer 374

Histamine causes bronchioles to constrict, increases mucus secretion, and dilates blood vessels, making them more permeable.

Question 375

How long do symptoms of an allergic reaction usually last?

Answer 375

Symptoms generally last about half an hour after contact with the allergen ceases.

Question 376

What is used to counteract allergic reactions?

Answer 376

Over-the-counter antihistamines are commonly used to counteract the effects of allergic reactions.

Question 377

What is anaphylactic shock?

Answer 377

Anaphylactic shock is a life-threatening systemic allergic reaction that occurs when an allergen rapidly enters the bloodstream and causes widespread histamine release.

Question 378

What are the symptoms and risks associated with anaphylactic shock?

Answer 378

Anaphylactic shock leads to widespread bronchiole constriction, decreased blood volume, reduced blood pressure, and can result in circulatory collapse and death.

Question 379

How is anaphylactic shock treated?

Answer 379

Anaphylactic shock is treated with an injection of adrenaline (epinephrine), which dilates bronchioles and constricts blood vessels to restore blood pressure and maintain blood flow.

Question 380

1. Which of the following is NOT a component of the lymphoid system?
   a) Lymph nodes
   b) Spleen
   c) Bone marrow
   d) Liver

Answer 380

d) Liver

Question 381

What is the primary function of lymph nodes?
a) Production of red blood cells
b) Filtering lymph to remove pathogens
c) Digestion of nutrients
d) Regulation of body temperature

Answer 381

b) Filtering lymph to remove pathogens

Question 382

Which component of the lymphoid system is involved in the maturation of T cells?
a) Spleen
b) Lymph nodes
c) Thymus
d) Bone marrow

Answer 382

c) Thymus

Question 383

hat is the role of macrophages in the innate immune system?
a) Produce antibodies
b) Present antigens to T cells
c) Destroy pathogens through phagocytosis
d) Activate B cells

Answer 383

c) Destroy pathogens through phagocytosis

Question 384

Which of the following describes an antigen?
a) A substance that activates the immune system
b) A type of white blood cell
c) A hormone that regulates immune responses
d) A structure that transports lymph

Answer 384

a) A substance that activates the immune system

Question 385

What does immunocompetence refer to?
a) The ability of immune cells to distinguish self from non-self
b) The ability of immune cells to remember past infections
c) The capacity of the immune system to mount a response against foreign invaders
d) The ability of the body to repair damaged tissues

Answer 385

c) The capacity of the immune system to mount a response against foreign invaders

Question 386

What is self-tolerance?
a) The immune system’s ability to destroy pathogens
b) The ability to recognize and ignore the body’s own cells
c) The capability to mount an immune response against all antigens
d) The development of antibodies specific to foreign antigens

Answer 386

b) The ability to recognize and ignore the body’s own cells

Question 387

What does immunological memory refer to?
a) The memory of previous infections in the brain
b) The body’s ability to remember and respond more rapidly to previously encountered antigens
c) The creation of new antigens after an infection
d) The ability to regenerate damaged tissues

Answer 387

b) The body’s ability to remember and respond more rapidly to previously encountered antigens

Question 388

What is the main function of helper T cells?
a) To directly kill infected cells
b) To secrete antibodies
c) To assist in the activation of B cells and cytotoxic T cells
d) To produce cytokines that cause inflammation

Answer 388

c) To assist in the activation of B cells and cytotoxic T cells

Question 389

How do cytotoxic T cells eliminate infected cells?
a) By producing antibodies that neutralize pathogens
b) By engulfing and digesting pathogens
c) By releasing perforins and granzymes to induce apoptosis
d) By secreting cytokines that attract other immune cells

Answer 389

c) By releasing perforins and granzymes to induce apoptosis

Question 390

What is the role of plasma cells in the immune system?
a) To produce and secrete antibodies
b) To present antigens to T cells
c) To regulate immune responses
d) To destroy infected cells directly

Answer 390

a) To produce and secrete antibodies

Question 391

Which type of immune response involves the production of IgG antibodies?
a) Primary immune response
b) Secondary immune response
c) T cell-mediated response
d) Innate immune response

Answer 391

b) Secondary immune response

Question 392

How does a vaccine contribute to immunity?
a) By providing immediate protection against infection
b) By stimulating a primary immune response to generate memory cells
c) By destroying existing pathogens in the body
d) By neutralizing antibodies already present

Answer 392

b) By stimulating a primary immune response to generate memory cells

Question 393

Which immune disorder is characterized by a lack of effective immune response due to missing or non-functional T and B cells?
a) Autoimmune disease
b) Immediate hypersensitivity
c) Immunodeficiency
d) Allergy

Answer 393

c) Immunodeficiency

Question 394

In which condition does the immune system mistakenly attack normal body tissues?
a) Immunodeficiency
b) Autoimmune disease
c) Anaphylaxis
d) Allergic reaction

Answer 394

b) Autoimmune disease

Question 395

What triggers an immediate hypersensitivity reaction?
a) Autoantibodies attacking normal cells
b) Pathogens invading the body
c) Overreaction to harmless antigens
d) The body’s failure to produce sufficient antibodies

Answer 395

c) Overreaction to harmless antigens

Question 396

Which type of antibody is primarily involved in allergic reactions?
a) IgM
b) IgG
c) IgA
d) IgE

Answer 396

d) IgE

Question 397

What happens during anaphylactic shock?
a) The body produces excessive antibodies
b) Histamine release leads to widespread bronchiole constriction and decreased blood pressure
c) The immune system becomes overactive and destroys healthy cells
d) There is a gradual increase in IgG levels in response to an allergen

Answer 397

b) Histamine release leads to widespread bronchiole constriction and decreased blood pressure

Question 398

What is the primary treatment for anaphylactic shock?
a) Antihistamines
b) Antibiotics
c) Adrenaline (epinephrine)
d) Antiviral medication

Answer 398

c) Adrenaline (epinephrine)

Question 399

What distinguishes a secondary immune response from a primary immune response?
a) The time it takes for antibodies to peak
b) The type of antibodies produced
c) The speed and magnitude of the response
d) The type of immune cells activated

Answer 399

c) The speed and magnitude of the response

Question 400

List the physical and chemical surface barriers that will prevent bacteria from entering the body.

Answer 400

Physical barriers:
* intact skin & mucous membranes
* Hairs (skin and nose)
* Cilia
* Normal flora
Chemical barriers:
* Sweat, saliva and tears
* Sebum
* Mucus
* Gastric juice

Question 401

What is involved in the first line of defence?

Answer 401

Physical and chemical surface barriers

Question 402

What is involved in the second line of defence?

Answer 402

Internal defences including:
* Macrophages & neutrophils
* Natural killer cells
* Complement
* Interferons
* Pyrogens
* Inflammation

Question 403

If bacteria breach the body’s first line of defence, briefly describe how complement and macrophages/neutrophils (internal defences) will directly destroy the bacteria.

Answer 403

Macrophages & neutrophils → phagocytose (ingest) & destroy bacteria via lysosomal enzymes

Complement form MAC (membrane attack complex) in bacterial cell membrane → lyse bacteria

Question 404

2. Viruses can be easily inhaled when an infected person sneezes or coughs.
   a) Identify the physical and chemical surface barriers that operate within the respiratory tract.

Answer 404

Physical barriers
* Nasal hairs
* Mucociliary escalator
* Cough reflex
Chemical barrier
* Mucus (lysozymes)

Question 405

b) If a virus breaches the body’s surface barriers, internal defences will be activated to prevent the virus from spreading throughout the body.
(i) Identify the internal defence that inhibits viral replication.

Answer 405

The internal defense that inhibits viral replication is interferon. When a cell is infected with a virus, it releases interferons, which are signaling proteins. These proteins help to boost the immune response by:
* Inhibiting Viral Replication
* Activating Immune Cells
* Increasing Antigen Presentation

Question 406

(ii) Describe how natural killer (NK) cells destroy virus-infected body cells.

Answer 406

Macrophages & neutrophils phagocytose (ingest) & destroy bacteria via lysosomal enzymes
NK cells release:
* perforins → create pores in the target cell membrane
* granzymes → induce apoptosis

Question 407

(iii) Describe how complement will help eliminate virus particles (free virus).

Answer 407

• Recruit macrophages & neutrophils to sites of virus (enemy) invasion
• Opsonisation – complement coats virus particles (enemy) to enhance phagocytosis (easier to identify & tastier to eat)

Question 408

(iv) Viral-induced damage to the respiratory tract’s epithelial cells will result in inflammation. How does the inflammatory response help eliminate the virus?

Answer 408

The inflammatory mediators released by damaged tissues will cause local arterioles to dilate and capillaries to become more permeable. This brings more macrophages, neutrophils and complement to the area.

Question 409

Use the terms provided to complete the concept map summarising how adaptive defences interact to produce an immune response.

Perforins and granzymes
Memory TC cells
Ag-specific TH cells
Plasma cells
Complement
Ag-specific TC cells
Macrophages/neutrophils
Cytokines
Ag-specific antibodies

Answer 409

Question 410

1. T and B cells are immunocompetent and self-tolerant. What do these two terms mean?

Answer 410

Self-tolerance: T and B cells can recognise self-antigens from non-self-antigens (they should not see self-antigens as foreign)

Immunocompetent: Each T and B cell recognises and binds to one specific antigen via their surface receptor.

Question 411

2. What type of immune disorder results if self-tolerance fails? Give an example of this type of disorder.

Answer 411

If self-tolerance fails → autoimmune disease (e.g., Type I diabetes mellitus, multiple sclerosis)

Question 412

3. Explain the statement “no T helper cells, no immune response” and give an example of a disease where this is the case.

Answer 412

T helper cells release cytokines that help turn on a cellular and humoral immune response. Thus, no helper T cells = no cellular or humoral immune response
E.g. AIDS

Question 413

1. In a primary immune response, which class of antibody is produced first?

Answer 413

IgM

Question 414

2. In a secondary immune response, which class of antibody rapidly rises to high blood levels?

Answer 414

IgG

Question 415

Case Scenario: Mary finds out she has been exposed to rubella (“German Measles”). She is concerned she might have contracted the disease, so she goes to see her doctor. The doctor takes a blood sample and sends it to a lab for the measurement of antibodies. The results show elevated levels of IgM and very low levels of IgG antibodies to the rubella virus.
3. Based on Mary’s blood antibody results (elevated IgM, very low levels of IgG).
a) Are Mary’s adaptive defences producing a primary or secondary immune response to the virus?

Answer 415

Primary immune response

Question 416

Case Scenario: Mary finds out she has been exposed to rubella (“German Measles”). She is concerned she might have contracted the disease, so she goes to see her doctor. The doctor takes a blood sample and sends it to a lab for the measurement of antibodies. The results show elevated levels of IgM and very low levels of IgG antibodies to the rubella virus.
3. Based on Mary’s blood antibody results (elevated IgM, very low levels of IgG).
b) Do you think Mary has previously been vaccinated against rubella? Why?

Answer 416

No.
If she was vaccinated, her memory T and B cells would have quickly produced a secondary immune response and her blood antibody results would have had high levels of IgG.

Question 417

Case Scenario: Mary finds out she has been exposed to rubella (“German Measles”). She is concerned she might have contracted the disease, so she goes to see her doctor. The doctor takes a blood sample and sends it to a lab for the measurement of antibodies. The results show elevated levels of IgM and very low levels of IgG antibodies to the rubella virus.
3. Based on Mary’s blood antibody results (elevated IgM, very low levels of IgG).
c) Will she develop the disease? Why?

Answer 417

Most likely → as a primary immune response is a small response that takes time to develop it usually does not protect from illness

Question 418

Case Scenario: Mary finds out she has been exposed to rubella (“German Measles”). She is concerned she might have contracted the disease, so she goes to see her doctor. The doctor takes a blood sample and sends it to a lab for the measurement of antibodies. The results show elevated levels of IgM and very low levels of IgG antibodies to the rubella virus.
4. As part of Mary’s primary immune response to the rubella virus, antibodies will bind to virus particles (free virus) in body fluids and cytotoxic T cells will destroy virus-infected body cells.

a) How will the virus particles bound by antibodies (Ag-Ab complexes) be destroyed?

Answer 418

Complement – opsoinses Ag-Ab complexes to enhance phagocytosis (opsonisation)

Macrophages & neutrophils – phagocytose and destroy Ag-Ab complexes by lysosomal enzymes

Question 419

Case Scenario: Mary finds out she has been exposed to rubella (“German Measles”). She is concerned she might have contracted the disease, so she goes to see her doctor. The doctor takes a blood sample and sends it to a lab for the measurement of antibodies. The results show elevated levels of IgM and very low levels of IgG antibodies to the rubella virus.
4. As part of Mary’s primary immune response to the rubella virus, antibodies will bind to virus particles (free virus) in body fluids and cytotoxic T cells will destroy virus-infected body cells.
b) How will effector (activated) cytotoxic T cells destroy virus-infected body cells?

Answer 419

They will bind to virus-infected body cells and release perforins which create pores in the target cell membrane & granzymes which induce apoptosis

Question 420

5. Why are vaccines considered beneficial?

Answer 420

Vaccines:
provide the first antigen encounter
activate a primary immune response
generate memory T and B cells
prime the body for a secondary immune response that protects from illness

Question 421

1. Innate defences include:
   a. B Cells
   b. plasma cells
   c. cytotoxic T cells
   d. intact skin

Answer 421

1. Innate defences include:
   a. B Cells
   b. plasma cells
   c. cytotoxic T cells
   d. intact skin

Question 422

2. Sweat, saliva and tears are all:
   a. chemical barriers
   b. internal defences
   c. adaptive defences
   d. physical barriers

Answer 422

2. Sweat, saliva and tears are all:
   a. chemical barriers
   b. internal defences
   c. adaptive defences
   d. physical barriers

Question 423

3. Natural Killer cells destroy virus-infected cells by secreting:
   a. complement
   b. perforins and granzymes
   c. lysosomal enzymes
   d. sebum

Answer 423

3. Natural Killer cells destroy virus-infected cells by secreting:
   a. complement
   b. perforins and granzymes
   c. lysosomal enzymes
   d. sebum

Question 424

4. Pyrogens:
   a. lyse bacteria
   b. form a membrane attack complex
   c. increase body temperature
   d. phagocytose pathogens

Answer 424

4. Pyrogens:
   a. lyse bacteria
   b. form a membrane attack complex
   c. increase body temperature
   d. phagocytose pathogens

Question 425

5. Helper T cells secrete:
   a. gastric juice
   b. lysosomal enzymes
   c. cytokines
   d. perforins

Answer 425

5. Helper T cells secrete:
   a. gastric juice
   b. lysosomal enzymes
   c. cytokines
   d. perforins

Question 426

6. Complement directly destroys cellular antigens by:
   a. forming a membrane attack complex (MAC)
   b. opsonisation
   c. inducing apoptosis
   d. enhancing phagocytosis

Answer 426

6. Complement directly destroys cellular antigens by:
   a. forming a membrane attack complex (MAC)
   b. opsonisation
   c. inducing apoptosis
   d. enhancing phagocytosis

Question 427

7. Which antibody is produced in large quantities during a secondary immune response?
   a. IgA.
   b. IgD.
   c. IgG.
   d. IgM.

Answer 427

7. Which antibody is produced in large quantities during a secondary immune response?
   a. IgA.
   b. IgD.
   c. IgG.
   d. IgM.

Question 428

8. An inflammatory response involves all the following except:
   a. histamine and prostaglandins
   b. mucocillary escalator
   c. macrophages and neutrophils
   d. complement

Answer 428

8. An inflammatory response involves all the following except:
   a. histamine and prostaglandins
   b. mucocillary escalator
   c. macrophages and neutrophils
   d. complement

Question 429

9. The antibody that mediates an allergic reaction is:
   a. IgA
   b. IgG
   c. IgM
   d. IgE

Answer 429

9. The antibody that mediates an allergic reaction is:
   a. IgA
   b. IgG
   c. IgM
   d. IgE

Question 430

10. Autoimmune diseases occur when immune defences:
    a. are unable to mount an effective response
    b. attack normal body cells
    c. overreact to a harmless antigen
    d. are absent

Answer 430

10. Autoimmune diseases occur when immune defences:
    a. are unable to mount an effective response
    b. attack normal body cells
    c. overreact to a harmless antigen
    d. are absent