Week 6: Lymphoid & Immune System Flashcards
T/F: The lymphatic system plays an important role in the regulation of interstital fluid and blood volume.
True
T/F: White blood cells can only be found in lymphoid organs and tissues.
False
T/F: Innate defences are non-specific defences because they will destroy ANY type of foreign material.
True
T/F: Cytokines are secreted by white blood cells to activate white blood cell.
True
Phagocytose and destroy foreign material via lysosomal enzymes - ____________________
Phagocytose and destroy foreign material via lysosomal enzymes - macrophages and neutrophils
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.
Intact skin and mucous membranes.
Normal flora.
Sweat, saliva and tears.
Inhibit with viral replication -____________________
Inhibit with viral replication - Interferons
Induce fever - ______________________
Induce fever - Pyrogens
Directly destroy cellular target by forming a membrane attack complex -
Directly destroy cellular target by forming a membrane attack complex - Complement
Isolates and removes foreign materials, repairs damaged tissues - _______________
Isolates and removes foreign materials, repairs damaged tissues - Immune response
T/F: Adaptive defences are present and active from birth.
False
T/F: The foreign invader that activates the body’s adaptive defences is called an antigen.
True
T/F: Immunocompetence and self-tolerance are two characteristics of T and B cells.
True
Match the adaptive defence to its function.
- Turns on an immune response -
- Directly destroys cellular antigens -
- Differentiates into plasma cells -
- Produces and secretes antibodies -
- Inactivates and tags antigens for destruction -
Plasma cells
Cytotoxic T cell
Helper T cell
B cell
Antibodies
- Turns on an immune response - Helper T cell
- Directly destroys cellular antigens - Cytotoxic T cell
- Differentiates into plasma cells - B cell
- Produces and secretes antibodies - Plasma cells
- Inactivates and tags antigens for destruction - Antibodies
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.
Slow, short lived response.
Response produces a small amount of IgM and IgG antibodies.
Produces memory T and B cells.
T/F: Immunodeficiency diseases arise because the body’s immune defences are too vigorous and attack a harmless antigen that most people can tolerate.
False
T/F: Type 1 diabetes and rheumatoid arthritis are examples of an autoimmune disease.
True
Which of the following is involved in an allergic reaction.
Autoantibodies.
IgE
Histamine.
IgA
Cytotoxic T cells.
Mast cells and Basophils.
IgE
Histamine.
Mast cells and Basophils.
T/F: Lymph is excess intracellular fluid.
False
T/F: Lymph flows from the tissues back to the venous circulation via lymph vessels.
True
T/F: Lymph nodes filter lymph and prevent foreing materials from entering the blood and spreading throughout the body.
True
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
d) are present and active from birth
Lysozyme is an enzyme that destroys bacteria. Identify the innate defences that contain this enzyme.
Tears.
Saliva.
Sebum.
Mucus.
Gastric juice.
Sweat.
Tears.
Saliva.
Sweat
Macrophages and neutrophils ________ and destroy foreign materials by ____________ enzymes.
Macrophages and neutrophils PHAGOCYTOSE and destroy foreign materials by LYSOSOMAL enzymes.
Natural killer cells destroy virus-infected cells and cancerous cells by releasing __________ to induce _____________.
Natural killer cells destroy virus-infected cells and cancerous cells by releasing PERFORINS AND GRANZYMES to induce APOPTOSIS.
Interferons are cytokines that inhibit _______________.
Interferons are cytokines that inhibit VIRAL REPLICATION.
Complement refers to a group of proteins that destroy cellular enemies such as bacteria by forming a ___________ which induces __________________.
Complement refers to a group of proteins that destroy cellular enemies such as bacteria by forming a MEMBRANE ATTACK COMPLEX which induces CELL LYSIS.
___________ are a group of proteins which induce fever.
PYROGENS are a group of proteins which induce fever.
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
B) release cytokines that help turn on a cellular and humoral immune response
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
A) destroy cellular antigens by releasing perforins and granzymes
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
D) differentiate into plasma cells which produce antibodies
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
D) infects and destroys helper T cells
Define:
Lymphoid System
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.
Define:
Immune System
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.
Define:
Pathogen
Any microorganism, such as a virus, bacteria, fungus, or worm, that can cause disease within the host body.
Define:
Inflammation
A natural immune response characterized by redness, heat, swelling, and pain, often occurring in response to infection or injury.
Define:
Fever
An elevated body temperature that is a common immune response to infection, helping the body fight off pathogens.
Define:
Transplants
The medical procedure of transferring cells, tissues, or organs from one body to another, which requires careful management of immune responses to prevent rejection.
Define:
Immunodeficiency Diseases
Conditions where the immune system is weakened or not functioning properly, making the body more susceptible to infections and diseases.
Define:
Autoimmune Diseases
Diseases in which the immune system mistakenly attacks the body’s own cells, such as rheumatoid arthritis and type 1 diabetes.
Define:
Viruses
Pathogens that infect and replicate within body cells, often leading to the destruction of the infected cells.
Define:
Worms
Parasitic organisms that live in the intestines and cause various diseases in their host.
Define:
Bacteria
Microorganisms that multiply in body fluids and produce toxins, leading to damage of cells, tissues, and organs.
Define:
Lymphoid System
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.
Define:
Lymphatic System
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.
Define:
Lymph
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.
Define:
Interstitial Fluid
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.
Define:
Hydrostatic Pressure
The pressure exerted by fluid within blood vessels, delivering interstitial fluid to body tissues.
Define:
Colloid Osmotic Pressure
The pressure exerted by proteins in blood plasma, which pulls interstitial fluid back into the blood vessels.
Define:
Lymphatic Capillaries
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.
Define:
Lymph Nodes
Small, bean-shaped structures located along lymphatic vessels that filter lymph, trapping and removing foreign materials, and facilitating an immune response.
Define:
Lymphedema
A condition where excess interstitial fluid accumulates in body tissues due to an impaired lymphatic system, leading to swelling and increased risk of infection.
Define:
Elephantiasis
A tropical disease caused by parasitic worms blocking lymphatic vessels, leading to severe swelling, particularly in the lower limbs and scrotum.
Define:
White Blood Cells (WBCs)
Cells that are part of the immune system, responsible for defending the body against foreign materials, including bacteria, viruses, parasites, and cancerous cells.
Define:
Cytokines
Communication molecules produced by white blood cells that recruit or activate specific white blood cells to respond to infections or destroy foreign materials.
Define:
Interferons
A type of cytokine involved in the immune response, particularly in inhibiting viral replication within host cells.
Define:
Interleukin-1 (IL-1)
A cytokine that plays a key role in the regulation of immune and inflammatory responses to infections or injuries.
Define:
Interleukin-2 (IL-2)
A cytokine that stimulates the growth and activity of white blood cells, particularly T cells, as part of the immune response.
Define:
Primary Lymphoid Organs
Organs, such as red bone marrow and the thymus, where white blood cells are produced.
Define:
Secondary Lymphoid Organs and Tissues
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.
Define:
Innate Defenses (Non-Specific Defenses)
The immune system’s initial defense mechanisms that protect against any type of foreign material before it can enter or spread throughout the body.
Define:
Adaptive Defenses (Specific Defenses)
The immune system’s targeted response to specific pathogens that have spread and invaded the body, involving the generation of an immune response.
Define:
Surface Barriers
The body’s first line of defense against pathogens, including physical and chemical barriers like skin and mucous membranes.
Define:
Protective Proteins
Proteins found within the body that play a role in the immune system’s internal defenses, helping to identify and neutralize pathogens.
Define:
Immune Response
The body’s third line of defense, where the immune system generates a specific response to eliminate invading pathogens.
Define:
Physical Barriers
Structural defenses like the skin and mucous membranes that create a barrier to block foreign materials from penetrating the body.
Define:
Mucous Membranes
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.
Define:
Epithelial Cells
Cells forming the outer layer of the skin and mucous membranes, providing a protective barrier against foreign materials.
Define:
Accessory Structures
Structures like hair and cilia that assist in trapping and removing foreign materials from the body’s surfaces.
Define:
Mucociliary Escalator
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.
Define:
Normal Flora
Beneficial bacteria that colonize various body surfaces and cavities, inhibiting the growth of pathogens by competing for nutrients and space.
Define:
Chemical Barriers
Body secretions such as sweat, saliva, tears, sebum, mucus, and gastric juice that cleanse and protect body surfaces by destroying or trapping foreign materials.
Define:
Lysozyme
An enzyme found in sweat, saliva, and tears that specifically targets and destroys bacteria.
Define:
Sebum
An oily, acidic secretion produced by sebaceous glands that covers the skin, inhibiting the growth of pathogens and being toxic to some bacteria.
Define:
Mucus
A sticky, viscous fluid that lines the gastrointestinal and respiratory tracts, trapping foreign materials that enter internal passageways.
Define:
Gastric Juice
A digestive fluid in the stomach containing hydrochloric acid and the enzyme pepsin, which destroys foreign materials that enter the stomach.
Define:
First Line of Defense
The body’s initial protection against foreign materials, consisting of physical and chemical barriers that prevent entry.
Define:
Second Line of Defense
Internal defense mechanisms, including white blood cells, protective proteins, and inflammatory responses, that activate when the first line of defense is breached.
Define:
White Blood Cells
Immune cells, such as macrophages, neutrophils, and natural killer cells, that play key roles in defending the body against invaders.
Define:
Macrophages
Phagocytic white blood cells that engulf and digest foreign materials, including bacteria, viruses, and cancer cells.
Define:
Neutrophils
Phagocytic white blood cells that target and consume bacteria and other foreign materials, often indicating bacterial infection when elevated.
Define:
Natural Killer (NK) Cells
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.
Define:
Perforins
Proteins released by NK cells that create pores in the target cell membrane, allowing destructive enzymes to enter.
Define:
Granzymes
Enzymes released by NK cells that induce apoptosis, causing the target cell to self-destruct.
Define:
Interferons
Cytokines produced by white blood cells and virus-infected cells that interfere with viral replication and activate macrophages and NK cells.
Define:
Complement System
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.
Define:
Opsonization
A process where complement proteins coat foreign materials, making them easier for macrophages and neutrophils to identify and consume.
Define:
Inflammatory Response
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.
Define:
Histamine
A chemical released during inflammation that causes blood vessels to dilate and become more permeable, facilitating immune cell movement to the site of injury.
Define:
Prostaglandins
Chemicals released during inflammation that contribute to pain and swelling by increasing blood vessel permeability and amplifying the inflammatory response.
Define:
Pyrogens
Substances, including interleukin-1 and bacterial toxins, that induce fever by resetting the body’s hypothalamic thermostat to a higher temperature.
Define:
Apoptosis
A process of programmed cell death induced by immune cells to eliminate virus-infected or cancerous cells.
Define:
Membrane Attack Complex
A structure formed by complement proteins that creates holes in the membranes of target cells, leading to cell lysis and death.
Define:
Cell Metabolism
The set of life-sustaining chemical reactions in cells, which can be increased by fever to accelerate immune responses and recovery.
Define:
Fever
An increase in body temperature triggered by pyrogens, which can inhibit pathogen growth and speed up immune cell activity.
Define:
Third line of defence
Also known as adaptive defences, activated when innate defenses are breached, targeting specific pathogens and abnormal cells with a systemic immune response.
Define:
Antigen
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.
Define:
Antigen-Presenting Cells
Cells, such as macrophages and dendritic cells, that capture and display antigens on their surface to activate T cells in the adaptive immune response.
Define:
Immunocompetence
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.
Define:
Immunological Memory
The adaptive immune system’s ability to remember previously encountered antigens, leading to a faster and stronger immune response upon re-exposure.
Define:
Primary Immune Response
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.
Define:
Secondary Immune Response
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.
Define:
Self-Tolerance
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.
Define:
T Cells
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.
Define:
B Cells
A type of lymphocyte that mediates the humoral immune response by producing antibodies specific to antigens.
Define:
Helper T Cells
A subtype of T cells that activates both cytotoxic T cells and B cells, initiating the cellular and humoral immune responses.
Define:
Cytotoxic T Cells
A subtype of T cells that target and destroy infected or abnormal cells, such as cancer cells or virus-infected cells, by inducing apoptosis.
Define:
Cellular Immune Response
The immune response mediated by cytotoxic T cells, which involves the direct destruction of infected or abnormal cells.
Define:
Humoral Immune Response
The immune response mediated by B cells, characterized by the production of antibodies that target antigens in body fluids.
Define:
Antigen-Presenting Cells
Cells that capture and display antigens to T cells, initiating the activation of helper T cells in the adaptive immune response.
Define:
Cytokines
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.
Define:
Plasma Cells
Specialized B cells that produce and secrete large quantities of antibodies during the humoral immune response.
Define:
Antibodies
Proteins produced by plasma cells that specifically bind to antigens, forming complexes that tag the antigen for destruction by other immune cells or systems.
Define:
Complement System
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.
Define:
Phagocytosis
The process by which immune cells, such as macrophages, engulf and digest antigens or pathogens.
Define:
Immunoglobulins (Ig)
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.
Define:
Memory T Cells
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.
Define:
Memory B Cells
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.
Define:
IgM
The first class of antibodies produced during a primary immune response, which gradually increases in blood levels before being followed by IgG.
Define:
IgG
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.
Define:
Vaccine
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.
Define:
Edward Jenner
The English doctor who invented the first vaccine by using cowpox to protect against smallpox, laying the foundation for modern vaccination practices.
Define:
Smallpox
A highly contagious and deadly disease eradicated through vaccination, with the smallpox vaccine being the first successful vaccine ever developed.
Define:
IgE
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.
Define:
IgA
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.
Define:
IgD
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.
Define:
Immunodeficiency Diseases
Conditions where the immune system’s defenses are absent or not functioning properly, leading to an inability to generate an effective immune response.
Define:
Severe Combined Immunodeficiency (SCID)
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.
Define:
Acquired Immunodeficiency Syndrome (AIDS)
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.
Define:
Human Immunodeficiency Virus (HIV)
The virus that causes AIDS by infecting and destroying helper T cells, leading to a severely compromised immune system.
Define:
Autoimmune Diseases
Diseases in which the immune system mistakenly attacks the body’s own cells and tissues, failing to distinguish between self and non-self antigens.
Define:
Rheumatoid Arthritis
An autoimmune disease where the immune system attacks the joints, causing inflammation, pain, and eventual joint damage.
Define:
Type 1 Diabetes
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.
Define:
Multiple Sclerosis
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.
Define:
Hypersensitivities (Allergic Reactions)
Define:
Excessive immune responses to harmless antigens, known as allergens, leading to symptoms like itching, swelling, and breathing difficulties.
Define:
Allergen
A substance that causes an allergic reaction in susceptible individuals, such as dust, pollen, bee venom, or certain foods.
Define:
Mast Cells
Immune cells found in tissues that release histamine and other chemicals during an allergic reaction, contributing to symptoms like swelling and bronchoconstriction.
Define: Define:
Basophils
A type of white blood cell that releases histamine during allergic reactions, contributing to symptoms like swelling and bronchoconstriction.
Define:
Histamine
A chemical released by mast cells and basophils during an allergic reaction that causes symptoms like bronchoconstriction, increased mucus secretion, and blood vessel dilation.
Define:
Anaphylactic Shock
A severe, life-threatening systemic allergic reaction that causes widespread bronchoconstriction, decreased blood pressure, and potential circulatory collapse. It requires immediate treatment with adrenaline.
Adrenaline (Epinephrine)
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.
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.
Lymphoid System
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.
Immune System
What is …
Any microorganism, such as a virus, bacteria, fungus, or worm, that can cause disease within the host body.
Pathogen
What is …
A natural immune response characterized by redness, heat, swelling, and pain, often occurring in response to infection or injury.
Inflammation
What is …
An elevated body temperature that is a common immune response to infection, helping the body fight off pathogens.
Fever
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.
Transplants
What is …
Conditions where the immune system is weakened or not functioning properly, making the body more susceptible to infections and diseases.
Immunodeficiency Diseases
What is …
Diseases in which the immune system mistakenly attacks the body’s own cells, such as rheumatoid arthritis and type 1 diabetes.
Autoimmune Diseases
What is …
Pathogens that infect and replicate within body cells, often leading to the destruction of the infected cells.
Viruses
What is …
Parasitic organisms that live in the intestines and cause various diseases in their host.
Worms
What is …
Microorganisms that multiply in body fluids and produce toxins, leading to damage of cells, tissues, and organs.
Bacteria
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.
Lymphoid System
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.
Lymphatic System
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.
Lymph
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.
Interstitial Fluid
What is …
The pressure exerted by fluid within blood vessels, delivering interstitial fluid to body tissues.
Hydrostatic Pressure
What is …
The pressure exerted by proteins in blood plasma, which pulls interstitial fluid back into the blood vessels.
Colloid Osmotic Pressure
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.
Lymphatic Capillaries
What is …
Small, bean-shaped structures located along lymphatic vessels that filter lymph, trapping and removing foreign materials, and facilitating an immune response.
Lymph Nodes
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.
Lymphedema
What is …
A tropical disease caused by parasitic worms blocking lymphatic vessels, leading to severe swelling, particularly in the lower limbs and scrotum.
Elephantiasis
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.
White Blood Cells (WBCs)
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.
Cytokines
What is …
A type of cytokine involved in the immune response, particularly in inhibiting viral replication within host cells.
Interferons
What is …
A cytokine that plays a key role in the regulation of immune and inflammatory responses to infections or injuries.
Interleukin-1 (IL-1)
What is …
A cytokine that stimulates the growth and activity of white blood cells, particularly T cells, as part of the immune response.
Interleukin-2 (IL-2)
What is …
Organs, such as red bone marrow and the thymus, where white blood cells are produced.
Primary Lymphoid Organs
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.
Secondary Lymphoid Organs and Tissues
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.
Innate Defenses (Non-Specific Defenses)
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.
Adaptive Defenses (Specific Defenses)
What is …
The body’s first line of defense against pathogens, including physical and chemical barriers like skin and mucous membranes.
Surface Barriers
What is …
Proteins found within the body that play a role in the immune system’s internal defenses, helping to identify and neutralize pathogens.
Protective Proteins
What is …
The body’s third line of defense, where the immune system generates a specific response to eliminate invading pathogens.
Immune Response
What is …
Structural defenses like the skin and mucous membranes that create a barrier to block foreign materials from penetrating the body.
Physical Barriers
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.
Mucous Membranes
What is …
Cells forming the outer layer of the skin and mucous membranes, providing a protective barrier against foreign materials.
Epithelial Cells
What is …
Structures like hair and cilia that assist in trapping and removing foreign materials from the body’s surfaces.
Accessory Structures
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.
Mucociliary Escalator
What is …
Beneficial bacteria that colonize various body surfaces and cavities, inhibiting the growth of pathogens by competing for nutrients and space.
Normal Flora
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.
Chemical Barriers
What is …
An enzyme found in sweat, saliva, and tears that specifically targets and destroys bacteria.
Lysozyme
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.
Sebum
What is …
A sticky, viscous fluid that lines the gastrointestinal and respiratory tracts, trapping foreign materials that enter internal passageways.
Mucus
What is …
A digestive fluid in the stomach containing hydrochloric acid and the enzyme pepsin, which destroys foreign materials that enter the stomach.
Gastric Juice
What is …
The body’s initial protection against foreign materials, consisting of physical and chemical barriers that prevent entry.
First Line of Defense
What is …
Internal defense mechanisms, including white blood cells, protective proteins, and inflammatory responses, that activate when the first line of defense is breached.
Second Line of Defense
What is …
Immune cells, such as macrophages, neutrophils, and natural killer cells, that play key roles in defending the body against invaders.
White Blood Cells
What is …
Phagocytic white blood cells that engulf and digest foreign materials, including bacteria, viruses, and cancer cells.
Macrophages
What is …
Phagocytic white blood cells that target and consume bacteria and other foreign materials, often indicating bacterial infection when elevated.
Neutrophils
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.
Natural Killer (NK) Cells
What is …
Proteins released by NK cells that create pores in the target cell membrane, allowing destructive enzymes to enter.
Perforins
What is …
Enzymes released by NK cells that induce apoptosis, causing the target cell to self-destruct.
Granzymes
What is …
Cytokines produced by white blood cells and virus-infected cells that interfere with viral replication and activate macrophages and NK cells.
Interferons
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.
Complement System
What is …
A process where complement proteins coat foreign materials, making them easier for macrophages and neutrophils to identify and consume.
Opsonization
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.
Inflammatory Response
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.
Histamine
What is …
Chemicals released during inflammation that contribute to pain and swelling by increasing blood vessel permeability and amplifying the inflammatory response.
Prostaglandins
What is …
Substances, including interleukin-1 and bacterial toxins, that induce fever by resetting the body’s hypothalamic thermostat to a higher temperature.
Pyrogens
What is …
A process of programmed cell death induced by immune cells to eliminate virus-infected or cancerous cells.
Apoptosis
What is …
A structure formed by complement proteins that creates holes in the membranes of target cells, leading to cell lysis and death.
Membrane Attack Complex
What is …
The set of life-sustaining chemical reactions in cells, which can be increased by fever to accelerate immune responses and recovery.
Cell Metabolism
What is …
An increase in body temperature triggered by pyrogens, which can inhibit pathogen growth and speed up immune cell activity.
Fever
What is …
Also known as adaptive defences, activated when innate defenses are breached, targeting specific pathogens and abnormal cells with a systemic immune response.
Third line of defence
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.
Antigen
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.
Antigen-Presenting Cells
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.
Immunocompetence
What is …
The adaptive immune system’s ability to remember previously encountered antigens, leading to a faster and stronger immune response upon re-exposure.
Immunological Memory
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.
Primary Immune Response
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.
Secondary Immune Response
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.
Self-Tolerance
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.
T Cells
What is …
A type of lymphocyte that mediates the humoral immune response by producing antibodies specific to antigens.
B Cells
What is …
A subtype of T cells that activates both cytotoxic T cells and B cells, initiating the cellular and humoral immune responses.
Helper T Cells
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.
Cytotoxic T Cells
What is …
The immune response mediated by cytotoxic T cells, which involves the direct destruction of infected or abnormal cells.
Cellular Immune Response
What is …
The immune response mediated by B cells, characterized by the production of antibodies that target antigens in body fluids.
Humoral Immune Response
What is …
Cells that capture and display antigens to T cells, initiating the activation of helper T cells in the adaptive immune response.
Antigen-Presenting Cells
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.
Cytokines
What is …
Specialized B cells that produce and secrete large quantities of antibodies during the humoral immune response.
Plasma Cells
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.
Antibodies
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.
Complement System
What is …
The process by which immune cells, such as macrophages, engulf and digest antigens or pathogens.
Phagocytosis
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.
Immunoglobulins (Ig)
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.
Memory T Cells
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.
Memory B Cells
What is …
The first class of antibodies produced during a primary immune response, which gradually increases in blood levels before being followed by IgG.
IgM
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.
IgG
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.
Vaccine
What is …
The English doctor who invented the first vaccine by using cowpox to protect against smallpox, laying the foundation for modern vaccination practices.
Edward Jenner
What is …
A highly contagious and deadly disease eradicated through vaccination, with the smallpox vaccine being the first successful vaccine ever developed.
Smallpox
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.
IgE
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.
IgA
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.
IgD
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.
Immunodeficiency Diseases
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.
Severe Combined Immunodeficiency (SCID)
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.
Acquired Immunodeficiency Syndrome (AIDS)
What is …
The virus that causes AIDS by infecting and destroying helper T cells, leading to a severely compromised immune system.
Human Immunodeficiency Virus (HIV)
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.
Autoimmune Diseases
What is …
An autoimmune disease where the immune system attacks the joints, causing inflammation, pain, and eventual joint damage.
Rheumatoid Arthritis
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.
Type 1 Diabetes
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.
Multiple Sclerosis
What is …
Excessive immune responses to harmless antigens, known as allergens, leading to symptoms like itching, swelling, and breathing difficulties.
Hypersensitivities (Allergic Reactions)
What is …
A substance that causes an allergic reaction in susceptible individuals, such as dust, pollen, bee venom, or certain foods.
Allergen
What is …
Immune cells found in tissues that release histamine and other chemicals during an allergic reaction, contributing to symptoms like swelling and bronchoconstriction.
Mast Cells
What is …
A type of white blood cell that releases histamine during allergic reactions, contributing to symptoms like swelling and bronchoconstriction.
Basophils
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.
Histamine
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.
Anaphylactic Shock
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.
Adrenaline (Epinephrine)
How do the lymphoid and immune systems work together?
They work together to protect the body from harmful materials, such as pathogens and diseases.
How do viruses attack the body?
They infect body cells, replicate within those cells, and often destroy the cells they infect.
Where do worms typically reside in the body?
In the small or large intestines.
How do bacteria cause harm to the body?
They multiply in body fluids and secrete toxins that damage cells, tissues, and entire organ systems.
How do we remain relatively healthy despite constant exposure to pathogens?
Our health relies on the components of the lymphoid system working together to protect us from harmful materials.
What are the components of the lymphoid system?
The lymphatic system, lymphoid organs and tissues, white blood cells, and cytokines.
What does the lymphatic system consist of?
Lymphatic capillaries, lymphatic vessels, lymph nodes, and lymph.
What is the primary function of the lymphatic system?
To circulate body fluids, remove foreign materials, and transport white blood cells to infection sites.
What is lymph?
Lymph is excess interstitial fluid that enters lymphatic capillaries and becomes lymph.
What causes the remaining 3 liters of interstitial fluid to become lymph?
It enters lymphatic capillaries due to the imbalance between hydrostatic and colloid osmotic pressures.
What is the function of lymphatic capillaries?
They allow interstitial fluid, white blood cells, pathogens, and foreign materials to enter while preventing their return to body tissues.
How does lymph flow through the body?
It flows from lymphatic capillaries through lymph vessels and lymph nodes, eventually returning to the venous circulation near the heart.
What happens if the lymphatic system cannot return the 3 liters of interstitial fluid to the blood?
It leads to lymphedema, where fluid accumulates in body tissues.
What are common causes of lymphedema?
Removal of lymphatic vessels during surgery or blockage by tumors or pathogens.
What is elephantiasis and what causes it?
Elephantiasis is a tropical disease caused by a parasitic worm that blocks lymphatic vessels, especially in the lower limbs and scrotum.
What is the role of lymph nodes?
What is the role of lymph nodes?
What happens when a large number of pathogens are trapped in a lymph node?
The lymph node may become swollen and sore.
What are primary lymphoid organs?
The red bone marrow and the thymus.
What is the function of primary lymphoid organs?
They are responsible for producing white blood cells.
What are secondary lymphoid organs and tissues?
Lymph nodes, spleen, tonsils, appendix, and the tissues lining the gastrointestinal and urinary tracts.
What is the role of secondary lymphoid organs and tissues?
They trap and destroy foreign materials and activate immune responses.
What types of white blood cells are involved in defending the body?
Neutrophils, macrophages, mast cells, basophils, eosinophils, and lymphocytes.
What are cytokines?
Communication molecules that recruit or activate white blood cells to respond to infection.
What are the two main types of immune defenses?
Innate (non-specific) defenses and adaptive (specific) defenses.
How do innate defenses protect the body?
They destroy any type of foreign material before it can enter or spread throughout the body.
How do adaptive defenses protect the body?
They target specific enemies that are spreading and invading the body.
What are the three lines of defense in the immune system?
Body’s surface barriers.
Internal defenses like white blood cells and protective proteins.
Immune response generation.
Why are the first and second lines of defense called innate defenses?
Because they are present and active from birth and protect against any type of foreign material.
How do the first and second lines of defense respond to foreign materials?
They respond within minutes to prevent foreign materials from entering the body and stop those that do enter from spreading.
What are the functions of the body’s surface barriers in the first line of defense?
To prevent foreign materials from entering, trap and remove foreign materials, expel foreign materials, and secrete destructive chemicals and enzymes.
What are some examples of physical barriers in the first line of defense?
The skin and mucous membranes lining the gastrointestinal, respiratory, urinary, and reproductive tracts.
How do the accessory structures like hairs and cilia contribute to defense?
Hairs trap foreign materials, and cilia sweep materials away from respiratory surfaces towards the throat.
What is the role of normal flora in the body’s defense?
Normal flora inhibit pathogen survival by consuming nutrients and competing for space and attachment sites on body cells.
Where do normal flora commonly colonize?
The skin, upper respiratory tract, digestive tract, urinary tract, and reproductive tract.
What are some examples of chemical barriers in the body’s defense?
Sweat, saliva, tears, sebum, mucus, and gastric juice.
How do sweat, saliva, and tears contribute to defense?
They cleanse body surfaces and contain the enzyme lysozyme, which destroys bacteria.
What is the function of sebum?
To cover the skin surface with an oily, acidic secretion that inhibits pathogen growth and is toxic to some bacteria.
How does mucus contribute to the body’s defense?
It traps foreign materials that enter internal passageways such as the gastrointestinal and respiratory tracts.
What are the components of gastric juice, and how do they aid in defense?
Hydrochloric acid and the enzyme pepsin destroy foreign materials in the stomach.
What happens when the body’s first line of defense is breached?
The body’s internal defense mechanisms activate to prevent the invader from spreading throughout the body.
What types of cells are involved in the second line of defense?
Macrophages, neutrophils, and natural killer (NK) cells.
What do macrophages and neutrophils do?
They are phagocytic cells that engulf and destroy foreign materials, including bacteria, toxins, viruses, and cancerous cells.
How do macrophages and neutrophils destroy invaders?
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.
What indicates a bacterial infection in terms of white blood cells?
A high neutrophil count in the blood usually indicates a bacterial infection.
What is the role of natural killer (NK) cells?
They monitor the blood and lymph to detect and destroy virus-infected and cancerous cells before they spread.
How do NK cells destroy target cells?
NK cells release perforins to create pores in the target cell membrane and granzymes to induce apoptosis.
What are interferons and how do they function?
Interferons are cytokines that interfere with viral replication by prompting nearby cells to produce antiviral proteins. They can also activate macrophages and NK cells.
What is a symptom of interferons working in response to a viral infection?
Aching muscles and fever.
What is the complement system?
A group of approximately 20 plasma proteins that monitor body fluids and tissues for foreign materials and help eliminate invaders.
How do complement proteins enhance the immune response?
They recruit macrophages and neutrophils to the site of invasion, enhance phagocytosis through opsonization, and can directly destroy invaders.
What is opsonization?
A process where complement proteins make foreign materials easier for macrophages and neutrophils to identify and consume.
What happens during an inflammatory response?
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.
What triggers the inflammatory response?
Injured cells release inflammatory chemicals like histamine and prostaglandins, causing blood vessels to dilate and become more permeable.
What are the effects of increased blood flow and capillary permeability during inflammation?
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.
How does fever contribute to the body’s defense?
Fever, induced by pyrogens, raises the body’s temperature, which can inhibit the growth of some pathogens and increase cell metabolism, accelerating recovery.
What are pyrogens and what do they do?
Pyrogens are proteins that reset the body’s thermostat to a higher temperature, causing fever. They include interleukin-1, interferons, and some bacterial toxins.
How does a fever affect cell metabolism?
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.
What is the main purpose of the first and second lines of defense?
To immediately respond and protect the body from foreign materials and prevent them from spreading or invading.
What happens when the body’s innate defenses fail?
The adaptive defenses are activated to eliminate the invader.
How do adaptive defenses differ from innate defenses?
Adaptive defenses are acquired and develop throughout life, whereas innate defenses are present from birth.
What is an antigen?
An antigen is a foreign substance that activates the body’s adaptive defenses.
What are some examples of antigens?
Examples include proteins or polysaccharides on viruses or bacteria, bacterial toxins, pollen, egg white, and transplanted tissue proteins.
Which cells are involved in the adaptive immune response?
T cells and B cells.
What role do antigen-presenting cells play in the adaptive immune response?
They capture, engulf, and present antigens to T cells, activating them.
How do antigen-presenting cells signal T cells?
By displaying antigens or antigen fragments on their cell surface.
What is immunocompetence?
The ability of T and B cells to recognize and bind to one specific antigen.
How do T cells and B cells recognize antigens?
T cells use T cell receptors, and B cells use antibody receptors.
What is self-tolerance?
The ability of T and B cells to be unresponsive to self-antigens or molecules normally found in the body.
Where do T cells and B cells mature?
B cells mature in the bone marrow, and T cells mature in the thymus.
What happens if T and B cells fail to develop self-tolerance?
They may attack normal body cells, potentially leading to autoimmune diseases.
What is immunological memory?
The ability of T and B cells to remember and mount a stronger response to previously encountered antigens.
What is the primary immune response?
The initial response to a new antigen, which produces a large number of memory T and B cells.
What is the secondary immune response?
A stronger, longer-lasting response to an antigen that the body has encountered before, thanks to memory T and B cells.
How is an immune response triggered?
An immune response is triggered when an antigen breaches the body’s first and second lines of defense and reaches a lymph node.
What are the two main types of immune responses?
The two main types are the cellular immune response and the humoral immune response.
Which cells mediate the cellular immune response?
Cytotoxic T cells mediate the cellular immune response.
Which cells mediate the humoral immune response?
B cells mediate the humoral immune response.
What is the role of helper T cells in the immune response?
Helper T cells activate both cytotoxic T cells and B cells by secreting cytokines.
How does a helper T cell become activated?
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.
What do effector helper T cells do?
Effector helper T cells secrete cytokines to activate cytotoxic T cells and B cells.
What is the function of cytotoxic T cells?
Cytotoxic T cells destroy cellular antigens such as cancer cells, foreign cells, and infected body cells.
How do cytotoxic T cells destroy their target cells?
Cytotoxic T cells release perforins to create pores in the target cell membrane and granzymes to induce apoptosis.
What is the role of B cells in the immune response?
B cells produce antibodies that target both cellular and non-cellular antigens.
What happens when a B cell is activated?
Activated B cells proliferate and differentiate into memory B cells and plasma cells, which secrete antibodies.
How do antibodies eliminate antigens?
Antibodies bind to antigens, forming complexes that are inactivated and tagged for destruction by macrophages, neutrophils, or complement proteins.
What is the complement system’s role in the immune response?
The complement system helps destroy antigens by forming membrane attack complexes or enhancing phagocytosis.
What are the five classes of antibodies?
IgM, IgG, IgA, IgD, and IgE.
How do antibodies differ from one another?
Each antibody class has structural differences, serves different biological roles, and is found in different locations in the body.
What is the difference between cellular and non-cellular antigens?
Cellular antigens include cells such as bacteria and cancer cells, while non-cellular antigens include substances like toxins and virus particles.
What happens if an antibody binds to a cellular antigen?
The complement system forms a membrane attack complex that lyses the antigen.
What happens if an antibody binds to a non-cellular antigen?
The complement system opsonizes the antigen, enhancing phagocytosis.
What characterizes a primary immune response?
A primary immune response is typically small, slow, and involves a limited number of antigen-specific T and B cells.
How long does it usually take for antibody levels to peak during a primary immune response?
It takes about eight to fourteen days for antibody levels to peak during a primary immune response.
Why might symptoms of infection begin within the first few days of exposure?
Symptoms often begin within the first few days due to the lag phase of the primary immune response, which does not immediately prevent illness.
Which antibody is always the first produced in a primary immune response?
IgM is always the first antibody produced when a new antigen enters the body.
What happens to IgM and IgG levels during a primary immune response?
IgM levels increase first, followed by a rise in IgG levels, which then decline as antibodies and antigens are phagocytosed.
What is the main function of a primary immune response?
The main function of a primary immune response is to produce thousands of antigen-specific memory T and B cells.
How do memory T and B cells contribute to a secondary immune response?
Memory T and B cells mount a rapid and powerful secondary immune response if the same antigen re-enters the body.
What is the primary difference between a primary and a secondary immune response?
A secondary immune response is faster and more robust, with high levels of IgG quickly appearing in the blood.
How do vaccines use the concept of the secondary immune response?
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.
Why do vaccines not cause illness?
Vaccines typically contain inactive or attenuated forms of antigens that cannot infect body cells.
How many doses are generally required for maximum protection with the Hepatitis B vaccine?
It generally requires two to five doses of the Hepatitis B vaccine to achieve maximum protection.
Who invented the first smallpox vaccine, and what was the basis of his discovery?
Edward Jenner invented the first smallpox vaccine based on the observation that people who had cowpox did not develop smallpox.
What was the outcome of widespread smallpox vaccination?
The widespread use of the smallpox vaccine led to the official eradication of the disease.
How does the immune response start?
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.
What role do cytokines play in the immune response?
Cytokines, particularly interleukin-2, help activate antigen-specific cytotoxic T cells and B cells.
How do B cells contribute to the humoral immune response?
B cells differentiate into plasma cells that secrete antibodies to inactivate and tag antigens for destruction.
What is the role of cytotoxic T cells in the cellular immune response?
Cytotoxic T cells destroy cellular antigens by releasing perforins and granzymes.
What does the immune response generate to protect against future infections?
The immune response generates thousands of long-lived memory helper T cells, B cells, and cytotoxic T cells.
What can cause immunodeficiency diseases?
Immunodeficiency diseases can be caused by the body’s immune defenses being absent or not functioning properly, resulting in an ineffective immune response.
What is severe combined immunodeficiency (SCID)?
SCID is a severe inherited immunodeficiency where individuals lack both T and B cells, making them unable to mount an effective immune response.
How can individuals with SCID survive?
Individuals with SCID may survive by living in sterile environments or receiving bone marrow transplants to provide functional T and B cells.
What virus causes acquired immunodeficiency syndrome (AIDS)?
AIDS is caused by the human immunodeficiency virus (HIV).
How does HIV affect the immune system?
HIV infects and destroys helper T cells, severely compromising the immune system and impairing both cellular and humoral immune responses.
What are common outcomes for patients with AIDS without treatment?
Without treatment, patients with AIDS typically survive 9 to 11 years, often dying from infections or cancers due to their weakened immune system.
What is an autoimmune disease?
An autoimmune disease occurs when the body’s immune system mistakenly attacks normal cells and tissues.
Give three examples of autoimmune diseases.
Rheumatoid arthritis, type 1 diabetes, and multiple sclerosis are examples of autoimmune diseases.
What can lead to autoimmune diseases?
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.
What are hypersensitivities or allergic reactions?
Hypersensitivities, or allergic reactions, occur when the immune system overreacts to harmless antigens that most people tolerate without issue.
What is an allergen?
An allergen is the substance that causes an allergic reaction, such as dust, pollen, bee venom, drugs, or certain foods.
What type of antibodies mediate most allergic reactions?
Most allergic reactions are mediated by IgE antibodies.
What happens during the first exposure to an allergen?
During the first exposure, plasma cells produce IgE antibodies, which bind to mast cells and basophils, but no symptoms typically occur.
How do symptoms of an allergic reaction occur upon re-exposure to an allergen?
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.
What effects does histamine have during an allergic reaction?
Histamine causes bronchioles to constrict, increases mucus secretion, and dilates blood vessels, making them more permeable.
How long do symptoms of an allergic reaction usually last?
Symptoms generally last about half an hour after contact with the allergen ceases.
What is used to counteract allergic reactions?
Over-the-counter antihistamines are commonly used to counteract the effects of allergic reactions.
What is anaphylactic shock?
Anaphylactic shock is a life-threatening systemic allergic reaction that occurs when an allergen rapidly enters the bloodstream and causes widespread histamine release.
What are the symptoms and risks associated with anaphylactic shock?
Anaphylactic shock leads to widespread bronchiole constriction, decreased blood volume, reduced blood pressure, and can result in circulatory collapse and death.
How is anaphylactic shock treated?
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.
- Which of the following is NOT a component of the lymphoid system?
a) Lymph nodes
b) Spleen
c) Bone marrow
d) Liver
d) Liver
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
b) Filtering lymph to remove pathogens
Which component of the lymphoid system is involved in the maturation of T cells?
a) Spleen
b) Lymph nodes
c) Thymus
d) Bone marrow
c) Thymus
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
c) Destroy pathogens through phagocytosis
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
a) A substance that activates the immune system
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
c) The capacity of the immune system to mount a response against foreign invaders
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
b) The ability to recognize and ignore the body’s own cells
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
b) The body’s ability to remember and respond more rapidly to previously encountered antigens
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
c) To assist in the activation of B cells and cytotoxic T cells
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
c) By releasing perforins and granzymes to induce apoptosis
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
a) To produce and secrete antibodies
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
b) Secondary immune response
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
b) By stimulating a primary immune response to generate memory cells
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
c) Immunodeficiency
In which condition does the immune system mistakenly attack normal body tissues?
a) Immunodeficiency
b) Autoimmune disease
c) Anaphylaxis
d) Allergic reaction
b) Autoimmune disease
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
c) Overreaction to harmless antigens
Which type of antibody is primarily involved in allergic reactions?
a) IgM
b) IgG
c) IgA
d) IgE
d) IgE
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
b) Histamine release leads to widespread bronchiole constriction and decreased blood pressure
What is the primary treatment for anaphylactic shock?
a) Antihistamines
b) Antibiotics
c) Adrenaline (epinephrine)
d) Antiviral medication
c) Adrenaline (epinephrine)
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
c) The speed and magnitude of the response
List the physical and chemical surface barriers that will prevent bacteria from entering the body.
Physical barriers:
* intact skin & mucous membranes
* Hairs (skin and nose)
* Cilia
* Normal flora
Chemical barriers:
* Sweat, saliva and tears
* Sebum
* Mucus
* Gastric juice
What is involved in the first line of defence?
Physical and chemical surface barriers
What is involved in the second line of defence?
Internal defences including:
* Macrophages & neutrophils
* Natural killer cells
* Complement
* Interferons
* Pyrogens
* Inflammation
If bacteria breach the body’s first line of defence, briefly describe how complement and macrophages/neutrophils (internal defences) will directly destroy the bacteria.
Macrophages & neutrophils → phagocytose (ingest) & destroy bacteria via lysosomal enzymes
Complement form MAC (membrane attack complex) in bacterial cell membrane → lyse bacteria
- 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.
Physical barriers
* Nasal hairs
* Mucociliary escalator
* Cough reflex
Chemical barrier
* Mucus (lysozymes)
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.
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
(ii) Describe how natural killer (NK) cells destroy virus-infected body cells.
Macrophages & neutrophils phagocytose (ingest) & destroy bacteria via lysosomal enzymes
NK cells release:
* perforins → create pores in the target cell membrane
* granzymes → induce apoptosis
(iii) Describe how complement will help eliminate virus particles (free virus).
- Recruit macrophages & neutrophils to sites of virus (enemy) invasion
- Opsonisation – complement coats virus particles (enemy) to enhance phagocytosis (easier to identify & tastier to eat)
(iv) Viral-induced damage to the respiratory tract’s epithelial cells will result in inflammation. How does the inflammatory response help eliminate the virus?
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.
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
- T and B cells are immunocompetent and self-tolerant. What do these two terms mean?
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.
- What type of immune disorder results if self-tolerance fails? Give an example of this type of disorder.
If self-tolerance fails → autoimmune disease (e.g., Type I diabetes mellitus, multiple sclerosis)
- Explain the statement “no T helper cells, no immune response” and give an example of a disease where this is the case.
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
- In a primary immune response, which class of antibody is produced first?
IgM
- In a secondary immune response, which class of antibody rapidly rises to high blood levels?
IgG
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?
Primary immune response
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?
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.
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?
Most likely → as a primary immune response is a small response that takes time to develop it usually does not protect from illness
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?
Complement – opsoinses Ag-Ab complexes to enhance phagocytosis (opsonisation)
Macrophages & neutrophils – phagocytose and destroy Ag-Ab complexes by lysosomal enzymes
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?
They will bind to virus-infected body cells and release perforins which create pores in the target cell membrane & granzymes which induce apoptosis
- Why are vaccines considered beneficial?
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
- Innate defences include:
a. B Cells
b. plasma cells
c. cytotoxic T cells
d. intact skin
- Innate defences include:
a. B Cells
b. plasma cells
c. cytotoxic T cells
d. intact skin
- Sweat, saliva and tears are all:
a. chemical barriers
b. internal defences
c. adaptive defences
d. physical barriers
- Sweat, saliva and tears are all:
a. chemical barriers
b. internal defences
c. adaptive defences
d. physical barriers
- Natural Killer cells destroy virus-infected cells by secreting:
a. complement
b. perforins and granzymes
c. lysosomal enzymes
d. sebum
- Natural Killer cells destroy virus-infected cells by secreting:
a. complement
b. perforins and granzymes
c. lysosomal enzymes
d. sebum
- Pyrogens:
a. lyse bacteria
b. form a membrane attack complex
c. increase body temperature
d. phagocytose pathogens
- Pyrogens:
a. lyse bacteria
b. form a membrane attack complex
c. increase body temperature
d. phagocytose pathogens
- Helper T cells secrete:
a. gastric juice
b. lysosomal enzymes
c. cytokines
d. perforins
- Helper T cells secrete:
a. gastric juice
b. lysosomal enzymes
c. cytokines
d. perforins
- Complement directly destroys cellular antigens by:
a. forming a membrane attack complex (MAC)
b. opsonisation
c. inducing apoptosis
d. enhancing phagocytosis
- Complement directly destroys cellular antigens by:
a. forming a membrane attack complex (MAC)
b. opsonisation
c. inducing apoptosis
d. enhancing phagocytosis
- Which antibody is produced in large quantities during a secondary immune response?
a. IgA.
b. IgD.
c. IgG.
d. IgM.
- Which antibody is produced in large quantities during a secondary immune response?
a. IgA.
b. IgD.
c. IgG.
d. IgM.
- An inflammatory response involves all the following except:
a. histamine and prostaglandins
b. mucocillary escalator
c. macrophages and neutrophils
d. complement
- An inflammatory response involves all the following except:
a. histamine and prostaglandins
b. mucocillary escalator
c. macrophages and neutrophils
d. complement
- The antibody that mediates an allergic reaction is:
a. IgA
b. IgG
c. IgM
d. IgE
- The antibody that mediates an allergic reaction is:
a. IgA
b. IgG
c. IgM
d. IgE
- 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
- 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
