p.12
Phagocytes and Their Functions
What are the two classes of phagocytes?
Microphages and macrophages.
p.58
Adaptive Immunity Mechanisms
What type of immunity are B cells responsible for?
Antibody-mediated immunity.
p.36
Types of Immunity: Active vs Passive
What is active immunity?
Immunity developed through exposure to pathogens.
p.37
Types of Immunity: Active vs Passive
How is naturally acquired passive immunity obtained?
Through antibodies acquired from the mother.
p.17
Phagocytes and Their Functions
What initiates the process of phagocytosis?
When a phagocyte attaches to a target (adhesion).
p.6
Innate Immunity Mechanisms
What is the role of physical barriers in the immune system?
They keep hazardous materials, such as biological pathogens, outside the body.
p.65
Inflammatory Response and Its Effects
What do macrophages increase the production of after binding?
Some genes that form proteins encouraging inflammation.
p.25
Complement System Activation
What are complement proteins?
30 special proteins found in plasma that form the complement system.
p.11
Innate Immunity Mechanisms
What role do secretions play in physical barriers?
They flush away materials and can kill or inhibit microorganisms.
p.4
Innate Immunity Mechanisms
What type of immunity is always non-specific and works the same way against any invading agent?
Innate (non-specific) immunity.
p.4
Adaptive Immunity Mechanisms
What type of immunity protects against specific pathogens?
Adaptive (specific) immunity.
p.31
Complement System Activation
What complex is generated by the activation of the common pathway?
The membrane attack complex (MAC).
p.51
Adaptive Immunity Mechanisms
How are antigenic fragments displayed on the plasma membrane?
By Class II MHC proteins.
p.64
Antibody-mediated immunity
What is the role of memory B cells?
They remain in reserve to respond to the next infection.
p.43
Immune System Overview
What is the primary focus of the Khan Academy website?
Providing free educational resources and courses.
p.5
Innate Immunity Mechanisms
What type of immunity is innate immunity?
Non-specific and born with.
p.50
T Cells and B Cells in Adaptive Immunity
What do Class II MHC proteins bind to?
Antigenic fragments from antigen processing of pathogens.
p.43
Immune System Overview
How does Khan Academy support learning?
Through instructional videos, practice exercises, and a personalized learning dashboard.
p.59
Adaptive Immunity Mechanisms
What type of immunity is associated with B cell sensitization?
Antibody-mediated immunity.
p.8
Inflammatory Response and Its Effects
What role do mast cells play in the inflammatory response?
They are resident cells in connective tissues that contribute to the inflammatory response.
p.14
Phagocytes and Their Functions
What activates macrophages?
The presence of pathogens.
p.35
Types of Immunity: Active vs Passive
What characterizes active immunity?
Antibodies develop after exposure to an antigen.
p.14
Phagocytes and Their Functions
How do macrophages respond to pathogens?
In several ways, including engulfing and destroying them.
p.39
Adaptive Immunity Mechanisms
What is the main feature of adaptive (specific) defenses?
They provide specific resistance (immunity).
p.4
T Cells and B Cells in Adaptive Immunity
What does adaptive immunity depend on?
The activities of lymphocytes.
p.41
Adaptive Immunity Mechanisms
What are the two main types of adaptive immunity?
Cell-mediated immunity and antibody-mediated immunity.
p.18
Inflammatory Response and Its Effects
What are cytokines?
Cell signaling molecules that aid in cell-to-cell communication in immune responses.
p.48
Adaptive Immunity Mechanisms
Where are Class I MHC proteins synthesized?
At the endoplasmic reticulum.
p.27
Complement System Activation
What is C5 convertase?
An enzyme complex involved in the complement system that cleaves C5 into C5a and C5b.
p.59
B Cells and T Cells in Adaptive Immunity
What binds to B cell receptors during sensitization?
Corresponding antigens in interstitial fluids.
p.43
Immune System Overview
What types of subjects can you find on Khan Academy?
A wide range of subjects including math, science, economics, and humanities.
p.36
Types of Immunity: Active vs Passive
What role do dead viruses play in immunity?
They are used in vaccines to induce active immunity.
p.8
Inflammatory Response and Its Effects
What is the inflammatory response?
A localized, tissue-level response that limits the spread of injury or infection.
p.50
T Cells and B Cells in Adaptive Immunity
What is the role of Class II MHC proteins in the immune response?
They are inserted in the plasma membrane to stimulate T cells.
p.23
Role of Interferons in Immunity
What is the function of interferons in the body?
To coordinate local activities and act as hormones affecting the whole body.
p.46
T Cells and B Cells in Adaptive Immunity
What is THC in the context of T cells?
It refers to T cell receptor (TCR) proteins involved in antigen recognition.
p.63
B Cells and Their Functions
What is the role of memory B cells?
They remain inactive until re-exposure to the same antigen.
p.16
Phagocytes and Their Functions
What distinguishes free macrophages from fixed macrophages?
Free macrophages can move throughout the body, while fixed macrophages are stationary.
p.7
Role of Interferons in Immunity
Do anti-viral proteins kill viruses directly?
No, they do not kill viruses per se.
p.25
Complement System Activation
What are the two usual activation pathways of the complement system?
Classical pathway and Alternative pathway.
p.38
Adaptive Immunity Mechanisms
What is adaptive immunity?
Immunity that is not present at birth and develops in response to exposure to specific antigens.
p.25
Complement System Activation
What triggers the alternative pathway of complement activation?
Common bacterial endotoxin.
p.54
T Cells and B Cells in Adaptive Immunity
When do Suppressor T Cells act?
After the initial immune response.
p.18
Inflammatory Response and Its Effects
What do cytokines stimulate?
The movement of cells towards sites of inflammation, infection, and trauma.
p.62
T Cells and B Cells in Adaptive Immunity
What is the role of a sensitized B cell in the immune response?
It is activated by Helper T cells to promote B cell activation and division.
p.9
Innate Immunity Mechanisms
What is the significance of eosinophils in the immune response?
They are involved in combating multicellular parasites and certain infections.
p.13
Phagocytes and Their Functions
What system do macrophages and monocytes make up?
The monocyte-macrophage system (reticuloendothelial system).
p.62
T Cells and B Cells in Adaptive Immunity
What are cytokines?
Signaling molecules that mediate communication between cells in the immune system.
p.21
Phagocytes and Their Functions
What is the role of perforin molecules?
To form pores in abnormal cells.
p.36
Types of Immunity: Active vs Passive
How is naturally acquired active immunity obtained?
Through environmental exposure to pathogens.
p.52
Phagocytes and Their Functions
What are phagocytic antigen-presenting cells (APCs)?
Cells that engulf and present antigens to T cells.
p.33
Inflammatory Response and Its Effects
What is one effect of inflammation?
Temporary repair and barrier against pathogens.
p.59
B Cells and T Cells in Adaptive Immunity
What happens to antigens during the sensitization of B cells?
They are taken into the B cell, processed, and reappear on the surface bound to Class II MHC protein.
p.2
Pathogens and Their Impact
What are pathogens?
Microorganisms that can cause disease.
p.37
Types of Immunity: Active vs Passive
What are the two forms of passive immunity?
Naturally acquired and artificially induced.
p.46
T Cells and B Cells in Adaptive Immunity
What role do T cells play in the immune response?
They help in the activation of other immune cells and directly kill infected cells.
p.32
Inflammatory Response and Its Effects
What triggers inflammation?
Any stimulus that kills cells or injures tissue.
p.30
Complement System Activation
What initiates the alternative pathway?
Interaction of several complement proteins, notably properdin, in the plasma triggered by exposure to foreign materials.
p.63
B Cells and Their Functions
What happens to B cells upon activation?
They differentiate into plasma cells and memory B cells.
p.31
Complement System Activation
What do the classical and alternative pathways activate?
The common pathway (C5 to C9).
p.8
Inflammatory Response and Its Effects
Why is a body temperature above 37°C not conducive to bacterial growth?
Because it can inhibit bacterial growth and enhance immune responses.
p.41
Antibody-Mediated Immunity
How do circulating antibodies attack pathogens?
Through direct physical and chemical attack.
p.38
Types of Immunity: Active vs Passive
What is passive immunity?
Immunity that is conferred by the transfer of antibodies from another source.
p.42
T Cells and B Cells in Adaptive Immunity
What do Memory T cells do in response to a remembered antigen?
Clone more of themselves.
p.10
Innate Immunity Mechanisms
What is fever and its effect on the body?
An elevation of body temperature that accelerates tissue metabolism and body defenses.
p.27
Complement System Activation
What does hydrolysis refer to?
The chemical breakdown of a compound due to reaction with water.
p.19
Innate Immunity Mechanisms
What do activated NK cells do first in immunological surveillance?
Identify and attach to abnormal cells (non-selective).
p.28
Complement System Activation
What is formed when C3b attaches to an antigen-antibody complex?
Membrane Attack Complex (MAC).
p.52
Phagocytes and Their Functions
What are Kupffer cells?
Macrophages located in the liver.
p.50
T Cells and B Cells in Adaptive Immunity
What are antigen-presenting cells (APCs) responsible for?
Activating T cells against foreign cells and proteins.
p.6
Innate Immunity Mechanisms
What is immune surveillance?
It constantly monitors normal tissues for potential threats.
p.45
Adaptive Immunity Mechanisms
Where are Class II MHC proteins found?
In the membranes of antigen-presenting cells (APCs) and lymphocytes.
p.24
Role of Interferons in Immunity
What is the role of Interferon alpha (α)?
It attracts and stimulates NK cells and enhances resistance to viral infection.
p.10
Complement System Activation
What is the role of complement in the immune system?
It is a system of circulating proteins that assist antibodies in the destruction of pathogens.
p.13
Phagocytes and Their Functions
What are the two classes of phagocytes?
Macrophages and microphages.
p.49
T Cells and B Cells in Adaptive Immunity
What do Memory T Cells do?
Await the reappearance of the antigen.
p.3
Adaptive Immunity Mechanisms
What role does the adaptive immune system play in pathogen invasion?
It destroys all invaded pathogens if the invasion continues.
p.49
T Cells and B Cells in Adaptive Immunity
What is the role of Suppressor T Cells?
To control or moderate immune response by T cells and B cells.
p.55
T Cells and B Cells in Adaptive Immunity
What is the function of the T cell receptor?
To recognize specific antigens presented by MHC molecules.
p.31
Phagocytes and Their Functions
How do complement proteins and antibodies assist in phagocytosis?
They attract phagocytes and make the target cell easier to engulf.
p.1
Role of Interferons in Immunity
What is the significance of interferons in the immune response?
They help to inhibit viral replication and activate immune cells.
p.10
Innate Immunity Mechanisms
What is activated during the inflammatory response?
Phagocytes and adaptive defenses.
p.61
T Cells and B Cells in Adaptive Immunity
What is the role of Helper T cells in B cell activation?
They activate sensitized B cells by binding to the same antigen.
p.23
Role of Interferons in Immunity
What are interferons?
Proteins (cytokines) released by activated lymphocytes and macrophages.
p.19
Innate Immunity Mechanisms
What is immunological surveillance?
A process carried out by natural killer (NK) cells to identify and attack abnormal cells.
p.52
Phagocytes and Their Functions
What are free and fixed macrophages?
Types of macrophages found in connective tissues.
p.7
Role of Interferons in Immunity
What are interferons?
Chemical messengers that trigger the production of anti-viral proteins in normal cells.
p.8
Inflammatory Response and Its Effects
How does fever affect the body?
It increases body metabolism, accelerates defenses, and inhibits some viruses and bacteria.
p.24
Role of Interferons in Immunity
Which cells produce Interferon alpha (α)?
Cells infected with viruses.
p.5
Innate Immunity Mechanisms
What are the seven major categories of innate immunity?
1. Physical barriers 2. Phagocytes 3. Immune surveillance 4. Interferons 5. Complement 6. Inflammatory response 7. Fever.
p.57
T Cells and B Cells in Adaptive Immunity
What types of immunity do cytokines from active T H cells stimulate?
Both cell-mediated and antibody-mediated immunity.
p.30
Complement System Activation
What can trigger the alternative pathway aside from foreign materials?
Spontaneous hydrolysis in C3 and cleavage of Factor B.
p.14
Phagocytes and Their Functions
How do macrophages destroy pathogens besides engulfing them?
By releasing toxic chemicals into interstitial fluid.
p.13
Phagocytes and Their Functions
How long does it take for monocytes to settle in tissues and become macrophages?
1 to 3 days after coming out from the bone marrow.
p.48
Adaptive Immunity Mechanisms
Where are abnormal peptides displayed after being processed?
On the plasma membrane by Class I MHC proteins.
p.15
Phagocytes and Their Functions
Where do fixed macrophages reside?
In specific tissues or organs.
p.3
Adaptive Immunity Mechanisms
How does Covid-19 bypass the innate immune system?
It directly triggers the adaptive immune response (vaccination).
p.58
Adaptive Immunity Mechanisms
How do B cells attack antigens?
By producing specific antibodies.
p.21
Phagocytes and Their Functions
What type of cell secretes perforin?
Natural Killer (NK) cells.
p.65
Inflammatory Response and Its Effects
What is the purpose of the pro-inflammatory cytokines secreted by macrophages?
To recruit more immune cells or activate specific immune cells.
p.23
Role of Interferons in Immunity
What role do cytokines play in the immune system?
They act as chemical messengers to coordinate local activities and can affect the whole body as hormones.
p.6
Phagocytes and Their Functions
What do phagocytes do?
They attack and remove dangerous microorganisms and ingest foreign pathogens.
p.63
B Cells and Their Functions
What type of cells are formed from activated B cells?
Plasma cells and memory B cells.
p.45
Adaptive Immunity Mechanisms
Where are Class I MHC proteins found?
In the membranes of all nucleated cells.
p.57
T Cells and B Cells in Adaptive Immunity
What is the role of active T H cells in the immune response?
They secrete cytokines that stimulate both cell-mediated and antibody-mediated immunity.
p.11
Innate Immunity Mechanisms
What substances in secretions can kill or inhibit microorganisms?
Enzymes, antibodies, and stomach acid.
p.2
Pathogens and Their Impact
What can cause food poisoning?
Bacterial unicellular pathogens.
p.60
Adaptive Immunity Mechanisms
What are antibodies?
Proteins produced by B cells that specifically bind to antigens.
p.13
Phagocytes and Their Functions
What are macrophages derived from?
Monocytes, which are circulating hematopoietic stem cells.
p.48
Adaptive Immunity Mechanisms
What is the role of the Golgi apparatus in the process of antigen presentation?
It helps transport MHC proteins to the plasma membrane.
p.44
T Cells and B Cells in Adaptive Immunity
What do T cells recognize?
Antigens that are bound to glycoproteins in plasma membranes.
p.42
T Cells and B Cells in Adaptive Immunity
What is the primary function of Cytotoxic T cells?
To attack cells infected by pathogens.
p.5
Innate Immunity Mechanisms
What is immune surveillance?
The monitoring of the body for signs of infection or disease.
p.31
Phagocytes and Their Functions
What do macrophage membranes contain that aids in opsonization?
Receptors that detect and bind to complement proteins and bound antibodies.
p.3
Pathogens and Their Impact
Why do some people die from influenza?
Because flu viruses tend to change their shapes, making them unrecognizable to the immune system.
p.56
T Cells and B Cells in Adaptive Immunity
What do Memory T H Cells do?
They await the reappearance of the antigen.
p.56
T Cells and B Cells in Adaptive Immunity
What role do Class II MHC proteins play in the immune response?
They activate Helper T Cells.
p.64
Antibody-mediated immunity
What do plasma cells synthesize and secrete?
Antibodies into interstitial fluid.
p.64
Antibody-mediated immunity
How are memory B cells similar to memory T cells?
Both remain in reserve to respond to future infections.
p.12
Phagocytes and Their Functions
Which types of cells are classified as microphages?
Neutrophils and eosinophils.
p.46
T Cells and B Cells in Adaptive Immunity
What do T cell receptors (TCR) recognize?
Specific antigens presented by other cells.
p.2
Pathogens and Their Impact
What is a common example of food poisoning?
Caused by bacterial pathogens.
p.52
Phagocytes and Their Functions
What are microglia?
Macrophages found in the central nervous system (CNS).
p.25
Complement System Activation
What is the function of the complement system?
To enhance the ability of antibodies to clear pathogens from an organism.
p.7
Role of Interferons in Immunity
What is the function of anti-viral proteins produced by interferons?
They block replication of viruses in neighboring cells.
p.26
Complement System Activation
What is the role of C3 convertase in the complement system?
It is a cylindrical structure that plays a key role in the activation of the complement pathways.
p.51
Phagocytes and Their Functions
What do phagocytic antigen-presenting cells (APCs) do?
They engulf extracellular pathogens.
p.9
Innate Immunity Mechanisms
What is immune surveillance?
The destruction of abnormal cells by natural killer (NK) cells in peripheral tissues.
p.60
T Cells and B Cells in Adaptive Immunity
What role do Class II MHC molecules play?
They present antigens to helper T cells, facilitating B cell activation.
p.40
T Cells and B Cells in Adaptive Immunity
What do T cells defend against?
Abnormal cells and pathogens inside cells.
p.31
Complement System Activation
What happens when an activated C3b protein attaches to a cell wall?
Additional complement proteins form a membrane attack complex (MAC) that destroys the target cell's integrity.
p.15
Phagocytes and Their Functions
What are the two types of macrophages?
Fixed macrophages and free macrophages.
p.10
Inflammatory Response and Its Effects
How does inflammation affect capillary permeability?
Capillary permeability is increased.
p.51
Phagocytes and Their Functions
What happens to a pathogen when it is killed by a phagocytic APC?
The cell is not infected.
p.1
Complement System Activation
How does the complement system enhance immunity?
By marking pathogens for destruction and promoting inflammation.
p.1
Inflammatory Response and Its Effects
What triggers the inflammatory response?
Injury or infection, leading to increased blood flow and immune cell recruitment.
p.42
T Cells and B Cells in Adaptive Immunity
What is the function of Suppressor T cells?
To inhibit the function of T cells and B cells.
p.65
Inflammatory Response and Its Effects
What do macrophages secrete after binding and digestion?
Pro-inflammatory cytokines.
p.58
B Cells and Their Functions
How many populations of B cells exist?
Millions, each with different antibody molecules.
p.61
T Cells and B Cells in Adaptive Immunity
How does a Helper T cell activate a B cell?
By binding to the MHC complex.
p.28
Complement System Activation
What activates the formation of the complex involving Cl?
Antigen-antibody reaction.
p.39
Adaptive Immunity Mechanisms
What type of immunity is characterized by specific resistance to antigens?
Adaptive (specific) immunity.
p.41
T Cells and B Cells in Adaptive Immunity
What is the role of activated T cells in adaptive immunity?
They find pathogens and attack them through phagocytosis or the release of chemical toxins.
p.6
Innate Immunity Mechanisms
What type of immunity is described by physical barriers and phagocytes?
Innate (non-specific) immunity.
p.35
Types of Immunity: Active vs Passive
What is passive immunity?
Antibodies are transferred from another source.
p.54
T Cells and B Cells in Adaptive Immunity
What are Memory T Cells?
T cells that remain in circulation and can quickly form cytotoxic T cells upon re-exposure to the same antigen.
p.49
T Cells and B Cells in Adaptive Immunity
What is the function of Cytotoxic T Cells?
To attack and destroy infected and abnormal cells displaying antigen.
p.35
Types of Immunity: Active vs Passive
What determines different forms of immunity?
Genetic factors and exposure.
p.40
Adaptive Immunity Mechanisms
What type of immunity do B cells provide?
Antibody-mediated immunity.
p.60
T Cells and B Cells in Adaptive Immunity
What is an inactive B cell?
A B cell that has not yet encountered its specific antigen.
p.40
T Cells and B Cells in Adaptive Immunity
What do B cells defend against?
Antigens and pathogens in body fluids.
p.4
Immune System Overview
What are the defense mechanisms that include white blood cells?
WBCs (white blood cells).
p.9
Innate Immunity Mechanisms
What happens to abnormal cells in the body?
They are lysed by immune cells.
p.38
Types of Immunity: Active vs Passive
What is artificially induced active immunity?
Immunity developed after administration of an antigen to prevent disease.
p.20
Innate Immunity Mechanisms
How does the Golgi apparatus adjust in NK cells when targeting abnormal cells?
It rotates itself to face towards the abnormal cell.
p.62
T Cells and B Cells in Adaptive Immunity
What is Class II MHC?
A molecule that presents antigens to Helper T cells.
p.37
Types of Immunity: Active vs Passive
What is passive immunity?
Immunity acquired without the immune system's direct involvement.
p.37
Types of Immunity: Active vs Passive
What is artificially induced passive immunity?
Immunity gained by an injection of antibodies.
p.61
T Cells and B Cells in Adaptive Immunity
What are the two types of cells that an activated B cell divides into?
Plasma cells and Memory B cells.
p.22
Innate Immunity Mechanisms
What role do NK cells play in viral infections?
They identify and destroy virus-infected cells.
p.12
Phagocytes and Their Functions
How do microphages compare in size and lifespan to other phagocytes?
They are smaller and short-lived.
p.22
Innate Immunity Mechanisms
What is the limitation of immunological surveillance?
It doesn't work all the time, leading to cancer growth.
p.47
T Cells and B Cells in Adaptive Immunity
What is the function of Class I MHC proteins?
They pick up small peptides in the cell and carry them to the surface as a label indicating the cell is infected.
p.28
Complement System Activation
What is the role of convertases in the complement system?
They help in the activation of C3 convertase.
p.9
Role of Interferons in Immunity
What are interferons?
Chemical messengers that coordinate defenses against viral infections.
p.53
Adaptive Immunity Mechanisms
What are non-phagocytic antigen-presenting cells (APCs)?
Cells that present antigens without engulfing them.
p.3
Innate Immunity Mechanisms
What is the primary function of the innate immune system?
To prevent the entry of pathogens by an effective barrier.
p.9
Innate Immunity Mechanisms
What do physical barriers do in the immune system?
They keep hazardous organisms and materials outside the body.
p.14
Phagocytes and Their Functions
What is one way macrophages assist other cells in destroying pathogens?
By binding to the pathogen.
p.53
Adaptive Immunity Mechanisms
Where are dendritic cells primarily located?
In lymph nodes and the spleen.
p.5
Innate Immunity Mechanisms
What role do physical barriers play in innate immunity?
They act as the first line of defense against pathogens.
p.9
T Cells and B Cells in Adaptive Immunity
What is the function of natural killer (NK) cells?
To destroy abnormal cells.
p.38
Types of Immunity: Active vs Passive
What is naturally acquired active immunity?
Immunity developed after natural exposure to antigens.
p.29
Complement System Activation
How does the alternative pathway differ from the classical pathway?
It achieves almost the same end result but through different mechanisms.
p.5
Role of Interferons in Immunity
What are interferons?
Proteins that help protect cells from viral infections.
p.42
T Cells and B Cells in Adaptive Immunity
What is the role of Helper T cells?
To stimulate the function of T cells and B cells.
p.56
T Cells and B Cells in Adaptive Immunity
What is required for the activation of Helper T Cells?
Antigen bound to Class II MHC protein.
p.36
Types of Immunity: Active vs Passive
What is artificially induced active immunity?
Immunity developed through vaccines containing pathogens.
p.16
Phagocytes and Their Functions
Where are microglia found?
In the central nervous system.
p.33
Inflammatory Response and Its Effects
How does inflammation prevent the spread of pathogens?
By creating a barrier in the affected area.
p.26
Complement System Activation
What does the membrane attack complex (MAC) do?
It causes cell lysis on the surface of bacteria.
p.11
Innate Immunity Mechanisms
What are physical barriers in the immune system?
They include the outer layer of skin, hair, and epithelial layers of internal passageways.
p.26
Complement System Activation
What is the end-point of the complement activation pathways?
The generation of the membrane attack complex (MAC).
p.19
Innate Immunity Mechanisms
What types of cells do NK cells attack?
Cancer cells and cells infected with viruses.
p.9
Phagocytes and Their Functions
What is the role of phagocytes in the immune system?
They engulf pathogens and cell debris.
p.25
Complement System Activation
How do complements work?
They work together in cascades.
p.30
Complement System Activation
What is the end result of the alternative pathway?
The attachment of an activated C3b protein to the bacterial cell wall.
p.2
Pathogens and Their Impact
What is the role of good bacteria in the gut?
They help with digestion and overall health.
p.30
Complement System Activation
Which proteins combine to form C3 convertase?
C3b, Properdin, Factor B, and Factor D.
p.3
Innate Immunity Mechanisms
How does the innate immune system respond to pathogens that enter the body?
It detects and destroys the pathogens as soon as they enter.
p.54
T Cells and B Cells in Adaptive Immunity
What is the role of Suppressor T Cells?
They secrete suppression factors to inhibit the responses of T and B cells.
p.38
Adaptive Immunity Mechanisms
How do you acquire immunity to a specific antigen?
By being exposed to that antigen or receiving antibodies from another source.
p.29
Complement System Activation
What is the end result of the classical pathway in the complement system?
Conversion of inactive C3 to activated C3b that attaches to the cell wall.
p.1
T Cells and B Cells in Adaptive Immunity
What are T cells responsible for in adaptive immunity?
They help in recognizing and destroying infected cells.
p.41
Adaptive Immunity Mechanisms
What is the significance of communication and feedback in the immune response?
It helps coordinate the immune response effectively.
p.10
Innate Immunity Mechanisms
What is the effect of pyrogens on body temperature?
They cause body temperature to rise above 37.2 °C.
p.5
Complement System Activation
What is the complement system?
A group of proteins that enhance the ability of antibodies and phagocytes to clear pathogens.
p.3
Pathogens and Their Impact
What happens during a second infection with a flu virus?
Symptoms may vary and the duration can change.
p.46
T Cells and B Cells in Adaptive Immunity
What is the primary function of T cells in cell-mediated immunity?
To recognize and respond to infected or abnormal cells.
p.27
Complement System Activation
What is the role of C5 convertase in the immune system?
It activates the complement component C5, leading to inflammation and opsonization.
p.17
Phagocytes and Their Functions
What happens after a phagocyte attaches to its target?
It surrounds the target with a vesicle.
p.19
Innate Immunity Mechanisms
What are perforins?
Proteins released by NK cells that lyse abnormal plasma membranes.
p.33
Inflammatory Response and Its Effects
What role does inflammation play in the body's defenses?
Mobilization of local and systemic defenses.
p.30
Complement System Activation
What is the role of the alternative pathway in the immune system?
It is important in the defense against bacteria, some parasites, and virus-infected cells.
p.12
Phagocytes and Their Functions
What is a distinguishing feature of microphages compared to neutrophils?
Microphages are more reddish than neutrophils.
p.6
Innate Immunity Mechanisms
What type of cells are involved in immune surveillance?
Natural killer (NK) cells.
p.47
T Cells and B Cells in Adaptive Immunity
What do T cells do with normal peptides?
T cells ignore normal peptides.
p.7
Complement System Activation
What is the complement system?
A system of circulating proteins that amplify in a cascade manner to damage pathogens.
p.48
Adaptive Immunity Mechanisms
What triggers antigen presentation by Class I MHC proteins?
Viral or bacterial infection of a body cell.
p.53
Adaptive Immunity Mechanisms
What type of cells are Langerhans cells?
A type of dendritic cell found in the skin.
p.7
Complement System Activation
How does the complement system assist in immunity?
It assists antibodies in the destruction of pathogens.
p.10
Inflammatory Response and Its Effects
What is inflammation?
A localized, tissue-level response that tends to limit the spread of an injury or infection.
p.31
Complement System Activation
What is the result of the MAC formation in bacteria?
Cell lysis through multiple pores.
p.41
Phagocytes and Their Functions
What is the function of activated phagocytes?
To engulf and destroy pathogens.
p.4
Adaptive Immunity Mechanisms
When does adaptive immunity develop?
After exposure to hazardous pathogens in the environment.
p.5
Phagocytes and Their Functions
What is the function of phagocytes in innate immunity?
They engulf and digest pathogens.
p.62
T Cells and B Cells in Adaptive Immunity
What is costimulation in the context of T cell activation?
It is the additional signal required for T cell activation alongside antigen recognition.
p.38
Types of Immunity: Active vs Passive
What is artificially induced passive immunity?
Immunity conferred by administration of antibodies to combat infection.
p.38
Innate Immunity Mechanisms
What characterizes innate immunity?
It is genetically determined and does not involve prior exposure or antibody production.
p.26
Complement System Activation
What is the result of activating either the classical or alternative pathways in the complement system?
It activates the common pathway, leading to the generation of the membrane attack complex (MAC).
p.12
Phagocytes and Their Functions
What is a key characteristic of microphages?
They leave the bloodstream and enter peripheral tissues to fight infections.
p.61
Adaptive Immunity Mechanisms
What type of immunity is associated with B cell activation?
Antibody-mediated immunity.
p.19
Innate Immunity Mechanisms
How do NK cells release perforins?
Through exocytosis of perforin vesicles.
p.49
T Cells and B Cells in Adaptive Immunity
What does an antigen bound to Class I MHC protein indicate?
That the cell is infected or otherwise abnormal.
p.18
Innate Immunity Mechanisms
What do cells use to distinguish 'self' from 'non-self'?
Pathogen-associated molecular patterns (PAMPs) unique to pathogens.
p.49
T Cells and B Cells in Adaptive Immunity
Which type of T cells are activated by Class I MHC proteins?
CD8 T Cells (Cytotoxic T Cells).
p.47
T Cells and B Cells in Adaptive Immunity
What activates T cells to destroy a cell?
Abnormal peptides or viral proteins.
p.55
T Cells and B Cells in Adaptive Immunity
What is the role of an Antigen-Presenting Cell (APC)?
To present foreign antigens to T cells.
p.48
Adaptive Immunity Mechanisms
What happens to abnormal peptides during an infection?
They appear in the cytoplasm and are incorporated into Class I MHC proteins.
p.29
Complement System Activation
What role does the attached C1 protein play in the classical pathway?
Acts as an enzyme, catalyzing reactions involving other complement proteins.
p.24
Role of Interferons in Immunity
What is the role of Interferon gamma (γ)?
It stimulates macrophage activity.
p.7
Complement System Activation
What happens when the complement system combines with an antigen-antibody complex?
It brings about the lysis of foreign cells.
p.40
Adaptive Immunity Mechanisms
What is the role of antibodies in adaptive immunity?
To identify and neutralize pathogens.
p.1
T Cells and B Cells in Adaptive Immunity
What is the role of B cells in the immune response?
They produce antibodies to neutralize pathogens.
p.20
Innate Immunity Mechanisms
What is the role of NK cells in relation to abnormal cells?
NK cells recognize and adhere to abnormal cells.
p.13
Phagocytes and Their Functions
How do the lifespans of macrophages compare to microphages?
Macrophages live longer than microphages.
p.31
Inflammatory Response and Its Effects
What is the role of histamine released by mast cells and basophils?
It increases local inflammation and accelerates blood flow to the region.
p.5
Inflammatory Response and Its Effects
What is the inflammatory response?
A protective response that involves redness, heat, swelling, and pain to help eliminate pathogens.
p.5
Innate Immunity Mechanisms
What role does fever play in innate immunity?
It helps to inhibit pathogen growth and enhances immune response.
p.21
Phagocytes and Their Functions
How can the action of perforin be metaphorically described?
Like poking a hole in a balloon, leading to deflation.
p.23
Role of Interferons in Immunity
Who releases interferons?
Activated lymphocytes and macrophages.
p.43
Immune System Overview
Is Khan Academy a paid service?
No, it is completely free to use.
p.33
Inflammatory Response and Its Effects
What is facilitated by inflammation in terms of tissue?
Repairs and regeneration.
p.46
T Cells and B Cells in Adaptive Immunity
What is secreted by T cells to help in the immune response?
Cytokines, which are signaling proteins.
p.60
Adaptive Immunity Mechanisms
What is sensitization in the context of the immune system?
The process by which B cells become activated upon exposure to antigens.
p.60
Pathogens and Their Impact
What are antigens?
Substances that can provoke an immune response.
p.41
T Cells and B Cells in Adaptive Immunity
What do activated B cells produce?
Cells that produce antibodies.
p.1
Immune System Overview
What is the primary function of the immune system?
To protect the body against pathogens and foreign substances.
p.24
Role of Interferons in Immunity
What is the function of Interferon beta (β)?
It slows inflammation in a damaged area.
p.1
Types of Immunity: Active vs Passive
What are the two main types of immunity?
Innate immunity and adaptive immunity.
p.9
Phagocytes and Their Functions
What types of cells are classified as fixed macrophages?
Monocytes and free macrophages.
p.38
Types of Immunity: Active vs Passive
What is active immunity?
Immunity that develops after exposure to antigens in the environment or through administration of an antigen.
p.51
Adaptive Immunity Mechanisms
Where are Class II MHC proteins produced?
In the endoplasmic reticulum.
p.60
T Cells and B Cells in Adaptive Immunity
What is a sensitized B cell?
A B cell that has been activated and is ready to produce antibodies.
p.3
Innate Immunity Mechanisms
How does sweat help in defending the body?
It washes away pathogens.
p.10
Inflammatory Response and Its Effects
What is the purpose of the clotting reaction during inflammation?
To wall off the region of injury or infection.
p.62
T Cells and B Cells in Adaptive Immunity
What is an antigen?
A substance that triggers an immune response.
p.62
T Cells and B Cells in Adaptive Immunity
What is the T cell receptor's role?
It recognizes specific antigens presented by Class II MHC molecules.
p.62
T Cells and B Cells in Adaptive Immunity
What is the outcome of Helper T cell activation?
It leads to the breakdown of the immune system and promotes B cell activation and division.
p.1
Phagocytes and Their Functions
What role do phagocytes play in the immune system?
They engulf and digest pathogens and debris.
p.53
Adaptive Immunity Mechanisms
What is the role of dendritic cells in immunity?
They present antigens to T cells, initiating immune responses.
p.3
Adaptive Immunity Mechanisms
What is one way the body prepares for future infections?
By remembering past infections.
p.60
Adaptive Immunity Mechanisms
What happens when antigens bind to antibody molecules?
It triggers a response from B cells, leading to their activation.
p.62
T Cells and B Cells in Adaptive Immunity
What is the function of Helper T cells in the immune system?
They promote B cell activation and division.
p.55
T Cells and B Cells in Adaptive Immunity
What is an inactive CD4 (T H) cell?
A T helper cell that has not yet been activated by an antigen.
p.38
Types of Immunity: Active vs Passive
What is naturally acquired passive immunity?
Immunity conferred by transfer of maternal antibodies across the placenta or in breast milk.
p.44
T Cells and B Cells in Adaptive Immunity
How do MHC proteins differ among individuals?
They vary genetically, leading to differences in antigen presentation.
p.10
Inflammatory Response and Its Effects
What is the significance of increased regional temperature during inflammation?
It helps accelerate the healing process.
p.62
T Cells and B Cells in Adaptive Immunity
What happens during the activation of Helper T cells?
They become activated and can then promote the immune response.
p.54
T Cells and B Cells in Adaptive Immunity
What is the function of Suppressor T Cells in the immune response?
To limit the immune reaction to a single stimulus.
p.29
Complement System Activation
What is the significance of C3b in the complement system?
It attaches to the bacterial cell wall.
p.44
T Cells and B Cells in Adaptive Immunity
What are MHC proteins?
Membrane glycoproteins that bind to antigens.
p.44
T Cells and B Cells in Adaptive Immunity
What does MHC stand for?
Major histocompatibility complex.
p.20
Innate Immunity Mechanisms
What is the function of the Golgi apparatus in NK cells?
The Golgi apparatus realigns to face the abnormal cell.
