What are the two classes of phagocytes?
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Microphages and macrophages.
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What are the two classes of phagocytes?
Microphages and macrophages.
What do NK cells use to identify cancer cells?
Tumor-specific antigens.
What type of immunity are B cells responsible for?
Antibody-mediated immunity.
What is active immunity?
Immunity developed through exposure to pathogens.
How is naturally acquired passive immunity obtained?
Through antibodies acquired from the mother.
What initiates the process of phagocytosis?
When a phagocyte attaches to a target (adhesion).
What is the role of physical barriers in the immune system?
They keep hazardous materials, such as biological pathogens, outside the body.
What do macrophages increase the production of after binding?
Some genes that form proteins encouraging inflammation.
What are complement proteins?
30 special proteins found in plasma that form the complement system.
What type of immunity is present at birth?
Innate immunity.
What role do secretions play in physical barriers?
They flush away materials and can kill or inhibit microorganisms.
When does adaptive immunity develop?
After birth.
What type of immunity is always non-specific and works the same way against any invading agent?
Innate (non-specific) immunity.
What type of immunity protects against specific pathogens?
Adaptive (specific) immunity.
What complex is generated by the activation of the common pathway?
The membrane attack complex (MAC).
How are antigenic fragments displayed on the plasma membrane?
By Class II MHC proteins.
What is the role of memory B cells?
They remain in reserve to respond to the next infection.
What is the primary focus of the Khan Academy website?
Providing free educational resources and courses.
What type of immunity is innate immunity?
Non-specific and born with.
What is the process called when B cells prepare for activation?
Sensitization.
What are fixed macrophages also known as?
Histiocytes.
What do Class II MHC proteins bind to?
Antigenic fragments from antigen processing of pathogens.
How does Khan Academy support learning?
Through instructional videos, practice exercises, and a personalized learning dashboard.
What type of immunity is associated with B cell sensitization?
Antibody-mediated immunity.
What role do mast cells play in the inflammatory response?
They are resident cells in connective tissues that contribute to the inflammatory response.
What is fever?
A high body temperature.
What are inactive CD4 T cells also known as?
Memory T H cells.
What activates macrophages?
The presence of pathogens.
What characterizes active immunity?
Antibodies develop after exposure to an antigen.
How do macrophages respond to pathogens?
In several ways, including engulfing and destroying them.
What is the main feature of adaptive (specific) defenses?
They provide specific resistance (immunity).
What does adaptive immunity depend on?
The activities of lymphocytes.
What are the two main types of adaptive immunity?
Cell-mediated immunity and antibody-mediated immunity.
What are cytokines?
Cell signaling molecules that aid in cell-to-cell communication in immune responses.
Where are Class I MHC proteins synthesized?
At the endoplasmic reticulum.
What is C5 convertase?
An enzyme complex involved in the complement system that cleaves C5 into C5a and C5b.
What binds to B cell receptors during sensitization?
Corresponding antigens in interstitial fluids.
What types of subjects can you find on Khan Academy?
A wide range of subjects including math, science, economics, and humanities.
What role do dead viruses play in immunity?
They are used in vaccines to induce active immunity.
What is the inflammatory response?
A localized, tissue-level response that limits the spread of injury or infection.
What is the role of Class II MHC proteins in the immune response?
They are inserted in the plasma membrane to stimulate T cells.
What is the function of interferons in the body?
To coordinate local activities and act as hormones affecting the whole body.
What is THC in the context of T cells?
It refers to T cell receptor (TCR) proteins involved in antigen recognition.
What is the role of memory B cells?
They remain inactive until re-exposure to the same antigen.
What distinguishes free macrophages from fixed macrophages?
Free macrophages can move throughout the body, while fixed macrophages are stationary.
How does inflammation get help from other parts of the body?
Through the bloodstream.
Do anti-viral proteins kill viruses directly?
No, they do not kill viruses per se.
What are the two usual activation pathways of the complement system?
Classical pathway and Alternative pathway.
What type of immunity do T cells provide?
Cell-mediated immunity.
What is produced by lysosomal action in phagocytic APCs?
Antigenic fragments.
What is adaptive immunity?
Immunity that is not present at birth and develops in response to exposure to specific antigens.
What triggers the alternative pathway of complement activation?
Common bacterial endotoxin.
When do Suppressor T Cells act?
After the initial immune response.
What do cytokines stimulate?
The movement of cells towards sites of inflammation, infection, and trauma.
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.
What is the significance of eosinophils in the immune response?
They are involved in combating multicellular parasites and certain infections.
What system do macrophages and monocytes make up?
The monocyte-macrophage system (reticuloendothelial system).
What are cytokines?
Signaling molecules that mediate communication between cells in the immune system.
What is the role of perforin molecules?
To form pores in abnormal cells.
How is naturally acquired active immunity obtained?
Through environmental exposure to pathogens.
What are phagocytic antigen-presenting cells (APCs)?
Cells that engulf and present antigens to T cells.
What is one effect of inflammation?
Temporary repair and barrier against pathogens.
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.
What are pathogens?
Microorganisms that can cause disease.
What are the two forms of passive immunity?
Naturally acquired and artificially induced.
What role do T cells play in the immune response?
They help in the activation of other immune cells and directly kill infected cells.
What triggers inflammation?
Any stimulus that kills cells or injures tissue.
What initiates the alternative pathway?
Interaction of several complement proteins, notably properdin, in the plasma triggered by exposure to foreign materials.
What happens to B cells upon activation?
They differentiate into plasma cells and memory B cells.
What is the optimal body temperature range for bacterial growth?
36-37°C.
What do the classical and alternative pathways activate?
The common pathway (C5 to C9).
Why is a body temperature above 37°C not conducive to bacterial growth?
Because it can inhibit bacterial growth and enhance immune responses.
What type of resistance is associated with innate immunity?
Non-specific resistance.
How do circulating antibodies attack pathogens?
Through direct physical and chemical attack.
What type of resistance is associated with adaptive immunity?
Specific resistance.
What is passive immunity?
Immunity that is conferred by the transfer of antibodies from another source.
What are some physical barriers the body uses to defend against pathogens?
Skin, mucus, and sweat.
What protein is associated with CD4 T helper cells?
CD4 protein.
What do Memory T cells do in response to a remembered antigen?
Clone more of themselves.
What is fever and its effect on the body?
An elevation of body temperature that accelerates tissue metabolism and body defenses.
What is the process by which macrophages move through capillary walls?
Emigration.
What does hydrolysis refer to?
The chemical breakdown of a compound due to reaction with water.
What do activated NK cells do first in immunological surveillance?
Identify and attach to abnormal cells (non-selective).
What is formed when C3b attaches to an antigen-antibody complex?
Membrane Attack Complex (MAC).
What are Kupffer cells?
Macrophages located in the liver.
What are the two classes of MHC proteins?
Class I and Class II.
What are antigen-presenting cells (APCs) responsible for?
Activating T cells against foreign cells and proteins.
What is immune surveillance?
It constantly monitors normal tissues for potential threats.
Where are Class II MHC proteins found?
In the membranes of antigen-presenting cells (APCs) and lymphocytes.
What is the role of Interferon alpha (α)?
It attracts and stimulates NK cells and enhances resistance to viral infection.
What do active helper T cells secrete?
Cytokines.
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.
What are the two classes of phagocytes?
Macrophages and microphages.
What do Memory T Cells do?
Await the reappearance of the antigen.
What role does the adaptive immune system play in pathogen invasion?
It destroys all invaded pathogens if the invasion continues.
What is the role of Suppressor T Cells?
To control or moderate immune response by T cells and B cells.
What is the function of the T cell receptor?
To recognize specific antigens presented by MHC molecules.
How do complement proteins and antibodies assist in phagocytosis?
They attract phagocytes and make the target cell easier to engulf.
What is the final destination of Class I MHC proteins after synthesis and processing?
The plasma membrane.
What are free macrophages also called?
Wandering macrophages.
What is the significance of interferons in the immune response?
They help to inhibit viral replication and activate immune cells.
What is activated during the inflammatory response?
Phagocytes and adaptive defenses.
What type of cells stimulate the immune response?
T cells and B cells.
What are Helper T Cells also known as?
CD4 T Cells.
What is the role of Helper T cells in B cell activation?
They activate sensitized B cells by binding to the same antigen.
What are interferons?
Proteins (cytokines) released by activated lymphocytes and macrophages.
What is immunological surveillance?
A process carried out by natural killer (NK) cells to identify and attack abnormal cells.
What do Helper T cells secrete to promote B cell activation?
Cytokines.
What are free and fixed macrophages?
Types of macrophages found in connective tissues.
What structure in NK cells forms perforin vesicles?
The Golgi apparatus.
What are interferons?
Chemical messengers that trigger the production of anti-viral proteins in normal cells.
What type of bacteria is commonly associated with the gut?
E. coli.
How does fever affect the body?
It increases body metabolism, accelerates defenses, and inhibits some viruses and bacteria.
What are examples of secretions that help in flushing away materials?
Sweat, mucus, and urine.
What does adaptive immunity respond to?
Specific antigens.
Which cells produce Interferon alpha (α)?
Cells infected with viruses.
What are the seven major categories of innate immunity?
What types of immunity do cytokines from active T H cells stimulate?
Both cell-mediated and antibody-mediated immunity.
What can trigger the alternative pathway aside from foreign materials?
Spontaneous hydrolysis in C3 and cleavage of Factor B.
How do macrophages destroy pathogens besides engulfing them?
By releasing toxic chemicals into interstitial fluid.
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.
What type of immunity is primarily associated with T cells?
Cell-mediated immunity.
Where are abnormal peptides displayed after being processed?
On the plasma membrane by Class I MHC proteins.
Where do fixed macrophages reside?
In specific tissues or organs.
How does Covid-19 bypass the innate immune system?
It directly triggers the adaptive immune response (vaccination).
What are Helper T cells also known as?
T H cells.
How do B cells attack antigens?
By producing specific antibodies.
What type of cell secretes perforin?
Natural Killer (NK) cells.
What is the purpose of the pro-inflammatory cytokines secreted by macrophages?
To recruit more immune cells or activate specific immune cells.
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.
What is inflammation also known as?
Inflammatory response.
What do phagocytes do?
They attack and remove dangerous microorganisms and ingest foreign pathogens.
What type of cells are formed from activated B cells?
Plasma cells and memory B cells.
Where are Class I MHC proteins found?
In the membranes of all nucleated cells.
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.
What substances in secretions can kill or inhibit microorganisms?
Enzymes, antibodies, and stomach acid.
What is the most rapid and effective activation pathway of the complement system?
The classical pathway.
What can cause food poisoning?
Bacterial unicellular pathogens.
What type of immunity is associated with the activation of T cells?
Cell-mediated immunity.
What are antibodies?
Proteins produced by B cells that specifically bind to antigens.
What are macrophages derived from?
Monocytes, which are circulating hematopoietic stem cells.
What binds to Class II MHC proteins?
Antigenic fragments.
What happens to blood flow during inflammation?
Blood flow is increased.
What is the role of the Golgi apparatus in the process of antigen presentation?
It helps transport MHC proteins to the plasma membrane.
What do T cells recognize?
Antigens that are bound to glycoproteins in plasma membranes.
What is the primary function of Cytotoxic T cells?
To attack cells infected by pathogens.
What is immune surveillance?
The monitoring of the body for signs of infection or disease.
What do macrophage membranes contain that aids in opsonization?
Receptors that detect and bind to complement proteins and bound antibodies.
Why do some people die from influenza?
Because flu viruses tend to change their shapes, making them unrecognizable to the immune system.
What do Memory T H Cells do?
They await the reappearance of the antigen.
What role do Class II MHC proteins play in the immune response?
They activate Helper T Cells.
What do plasma cells synthesize and secrete?
Antibodies into interstitial fluid.
What term describes the movement of phagocytes in response to chemicals in surrounding fluids?
Chemotaxis.
How are memory B cells similar to memory T cells?
Both remain in reserve to respond to future infections.
What happens to an abnormal cell when perforin is secreted?
It undergoes lysis.
Which types of cells are classified as microphages?
Neutrophils and eosinophils.
What do T cell receptors (TCR) recognize?
Specific antigens presented by other cells.
What is a common example of food poisoning?
Caused by bacterial pathogens.
What are microglia?
Macrophages found in the central nervous system (CNS).
What is the function of the complement system?
To enhance the ability of antibodies to clear pathogens from an organism.
What is the function of anti-viral proteins produced by interferons?
They block replication of viruses in neighboring cells.
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.
What do phagocytic antigen-presenting cells (APCs) do?
They engulf extracellular pathogens.
What do immune cells have on their surface to recognize pathogens?
Receptors for PAMPs.
What is immune surveillance?
The destruction of abnormal cells by natural killer (NK) cells in peripheral tissues.
What role do Class II MHC molecules play?
They present antigens to helper T cells, facilitating B cell activation.
What do T cells defend against?
Abnormal cells and pathogens inside cells.
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.
What type of immunity is described as non-specific?
Innate immunity.
What are the two types of macrophages?
Fixed macrophages and free macrophages.
How does inflammation affect capillary permeability?
Capillary permeability is increased.
What happens to a pathogen when it is killed by a phagocytic APC?
The cell is not infected.
What type of immunity are Cytotoxic T cells responsible for?
Cell-mediated immunity.
How does the complement system enhance immunity?
By marking pathogens for destruction and promoting inflammation.
What triggers the inflammatory response?
Injury or infection, leading to increased blood flow and immune cell recruitment.
What is the function of Suppressor T cells?
To inhibit the function of T cells and B cells.
What do macrophages secrete after binding and digestion?
Pro-inflammatory cytokines.
How many populations of B cells exist?
Millions, each with different antibody molecules.
How does a Helper T cell activate a B cell?
By binding to the MHC complex.
What do cells infected with viruses present on their plasma membranes?
Abnormal proteins.
What are plasma cells responsible for?
Antibody production.
What activates the formation of the complex involving Cl?
Antigen-antibody reaction.
What type of immunity is characterized by specific resistance to antigens?
Adaptive (specific) immunity.
What type of immunity is associated with the activation of T cells by APCs?
Cell-mediated 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.
What are the two types of E. coli?
Good and bad types.
What type of immunity is described by physical barriers and phagocytes?
Innate (non-specific) immunity.
What is passive immunity?
Antibodies are transferred from another source.
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.
What is the function of Cytotoxic T Cells?
To attack and destroy infected and abnormal cells displaying antigen.
What determines different forms of immunity?
Genetic factors and exposure.
What type of immunity do B cells provide?
Antibody-mediated immunity.
What is an inactive B cell?
A B cell that has not yet encountered its specific antigen.
What do B cells defend against?
Antigens and pathogens in body fluids.
What are the defense mechanisms that include white blood cells?
WBCs (white blood cells).
What happens to abnormal cells in the body?
They are lysed by immune cells.
What is artificially induced active immunity?
Immunity developed after administration of an antigen to prevent disease.
How does the Golgi apparatus adjust in NK cells when targeting abnormal cells?
It rotates itself to face towards the abnormal cell.
What is Class II MHC?
A molecule that presents antigens to Helper T cells.
What is passive immunity?
Immunity acquired without the immune system's direct involvement.
What is artificially induced passive immunity?
Immunity gained by an injection of antibodies.
What are the two types of cells that an activated B cell divides into?
Plasma cells and Memory B cells.
What type of macrophages are found in liver sinusoids?
Kupffer cells.
What role do NK cells play in viral infections?
They identify and destroy virus-infected cells.
How do microphages compare in size and lifespan to other phagocytes?
They are smaller and short-lived.
What is the limitation of immunological surveillance?
It doesn't work all the time, leading to cancer growth.
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.
Which cells are primarily involved in the coordinated action of adaptive immunity?
T cells and B cells.
What is the role of convertases in the complement system?
They help in the activation of C3 convertase.
What are interferons?
Chemical messengers that coordinate defenses against viral infections.
What are non-phagocytic antigen-presenting cells (APCs)?
Cells that present antigens without engulfing them.
What is the primary function of the innate immune system?
To prevent the entry of pathogens by an effective barrier.
What do macrophages use to destroy engulfed pathogens?
Lysosomal enzymes.
What do physical barriers do in the immune system?
They keep hazardous organisms and materials outside the body.
What is one way macrophages assist other cells in destroying pathogens?
By binding to the pathogen.
Where are dendritic cells primarily located?
In lymph nodes and the spleen.
What role do physical barriers play in innate immunity?
They act as the first line of defense against pathogens.
What is the function of natural killer (NK) cells?
To destroy abnormal cells.
Which cells secrete Interferon gamma (γ)?
T cells and NK cells.
What is naturally acquired active immunity?
Immunity developed after natural exposure to antigens.
How does the alternative pathway differ from the classical pathway?
It achieves almost the same end result but through different mechanisms.
What are interferons?
Proteins that help protect cells from viral infections.
What percentage of leukocytes in the human body are free macrophages?
2 - 10%.
What is the role of Helper T cells?
To stimulate the function of T cells and B cells.
What are Suppressor T cells also known as?
T S cells.
What indicates the presence of pathogens, toxins, or foreign proteins?
CD4 T Cells.
What is required for the activation of Helper T Cells?
Antigen bound to Class II MHC protein.
What is artificially induced active immunity?
Immunity developed through vaccines containing pathogens.
What pathway do Cl and C4 bind to?
Classical pathway.
Where are microglia found?
In the central nervous system.
How does inflammation prevent the spread of pathogens?
By creating a barrier in the affected area.
What does the membrane attack complex (MAC) do?
It causes cell lysis on the surface of bacteria.
What are physical barriers in the immune system?
They include the outer layer of skin, hair, and epithelial layers of internal passageways.
What is the end-point of the complement activation pathways?
The generation of the membrane attack complex (MAC).
What types of cells do NK cells attack?
Cancer cells and cells infected with viruses.
What is the role of phagocytes in the immune system?
They engulf pathogens and cell debris.
How do complements work?
They work together in cascades.
What is the end result of the alternative pathway?
The attachment of an activated C3b protein to the bacterial cell wall.
What is the role of good bacteria in the gut?
They help with digestion and overall health.
Which proteins combine to form C3 convertase?
C3b, Properdin, Factor B, and Factor D.
What does the classical pathway of complement activation involve?
Antibodies.
What is an abnormal immune system characterized by?
Attacking normal cells.
How does the innate immune system respond to pathogens that enter the body?
It detects and destroys the pathogens as soon as they enter.
What is the role of Suppressor T Cells?
They secrete suppression factors to inhibit the responses of T and B cells.
How do you acquire immunity to a specific antigen?
By being exposed to that antigen or receiving antibodies from another source.
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.
What are T cells responsible for in adaptive immunity?
They help in recognizing and destroying infected cells.
What is the significance of communication and feedback in the immune response?
It helps coordinate the immune response effectively.
What is the effect of pyrogens on body temperature?
They cause body temperature to rise above 37.2 °C.
What is the complement system?
A group of proteins that enhance the ability of antibodies and phagocytes to clear pathogens.
What happens during a second infection with a flu virus?
Symptoms may vary and the duration can change.
What is the primary function of T cells in cell-mediated immunity?
To recognize and respond to infected or abnormal cells.
What is the role of C5 convertase in the immune system?
It activates the complement component C5, leading to inflammation and opsonization.
What happens after a phagocyte attaches to its target?
It surrounds the target with a vesicle.
What are perforins?
Proteins released by NK cells that lyse abnormal plasma membranes.
What role does inflammation play in the body's defenses?
Mobilization of local and systemic defenses.
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.
What is a distinguishing feature of microphages compared to neutrophils?
Microphages are more reddish than neutrophils.
What type of cells are involved in immune surveillance?
Natural killer (NK) cells.
What do T cells do with normal peptides?
T cells ignore normal peptides.
What type of immunity is associated with MHC proteins?
Cell-mediated immunity.
What is the complement system?
A system of circulating proteins that amplify in a cascade manner to damage pathogens.
What triggers antigen presentation by Class I MHC proteins?
Viral or bacterial infection of a body cell.
What type of cells are Langerhans cells?
A type of dendritic cell found in the skin.
How does the complement system assist in immunity?
It assists antibodies in the destruction of pathogens.
What is inflammation?
A localized, tissue-level response that tends to limit the spread of an injury or infection.
What is the result of the MAC formation in bacteria?
Cell lysis through multiple pores.
What is the function of activated phagocytes?
To engulf and destroy pathogens.
When does adaptive immunity develop?
After exposure to hazardous pathogens in the environment.
What is the function of phagocytes in innate immunity?
They engulf and digest pathogens.
What type of immunity is associated with Memory T Cells and Suppressor T Cells?
Cell-mediated immunity.
Where are MHC proteins genetically coded?
In chromosome 6.
What is costimulation in the context of T cell activation?
It is the additional signal required for T cell activation alongside antigen recognition.
What is artificially induced passive immunity?
Immunity conferred by administration of antibodies to combat infection.
What characterizes innate immunity?
It is genetically determined and does not involve prior exposure or antibody production.
What is a mechanism by which some cancer cells avoid detection by NK cells?
Immunological escape.
What process do macrophages undergo after binding?
Phagocytosis.
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).
What is a key characteristic of microphages?
They leave the bloodstream and enter peripheral tissues to fight infections.
What type of immunity is associated with B cell activation?
Antibody-mediated immunity.
How do NK cells release perforins?
Through exocytosis of perforin vesicles.
What components are broken down in the complement activation process?
C4a, C4b, C2a, C2b.
What type of immunity is associated with phagocytic APCs?
Cell-mediated immunity.
What does an antigen bound to Class I MHC protein indicate?
That the cell is infected or otherwise abnormal.
What do cells use to distinguish 'self' from 'non-self'?
Pathogen-associated molecular patterns (PAMPs) unique to pathogens.
Which type of T cells are activated by Class I MHC proteins?
CD8 T Cells (Cytotoxic T Cells).
What activates T cells to destroy a cell?
Abnormal peptides or viral proteins.
What is the role of an Antigen-Presenting Cell (APC)?
To present foreign antigens to T cells.
What does C3 convertase bind with to form C5 convertase?
C3b.
What happens to abnormal peptides during an infection?
They appear in the cytoplasm and are incorporated into Class I MHC proteins.
Which cells secrete Interferon beta (β)?
Fibroblasts.
What role does the attached C1 protein play in the classical pathway?
Acts as an enzyme, catalyzing reactions involving other complement proteins.
What is the role of Interferon gamma (γ)?
It stimulates macrophage activity.
What happens when the complement system combines with an antigen-antibody complex?
It brings about the lysis of foreign cells.
What process enhances phagocytosis?
Opsonization.
What is the role of antibodies in adaptive immunity?
To identify and neutralize pathogens.
What is the role of B cells in the immune response?
They produce antibodies to neutralize pathogens.
What is the role of NK cells in relation to abnormal cells?
NK cells recognize and adhere to abnormal cells.
How do the lifespans of macrophages compare to microphages?
Macrophages live longer than microphages.
What is the role of histamine released by mast cells and basophils?
It increases local inflammation and accelerates blood flow to the region.
What is the inflammatory response?
A protective response that involves redness, heat, swelling, and pain to help eliminate pathogens.
What role does fever play in innate immunity?
It helps to inhibit pathogen growth and enhances immune response.
How can the action of perforin be metaphorically described?
Like poking a hole in a balloon, leading to deflation.
Who releases interferons?
Activated lymphocytes and macrophages.
What type of response is inflammation?
A localized response.
Is Khan Academy a paid service?
No, it is completely free to use.
What are alveolar macrophages also referred to as?
Phagocytic dust cells.
What is facilitated by inflammation in terms of tissue?
Repairs and regeneration.
What is secreted by T cells to help in the immune response?
Cytokines, which are signaling proteins.
What is sensitization in the context of the immune system?
The process by which B cells become activated upon exposure to antigens.
What triggers specific defenses in the immune response?
Antigen presentation.
What are antigens?
Substances that can provoke an immune response.
What do activated B cells produce?
Cells that produce antibodies.
What is the primary function of the immune system?
To protect the body against pathogens and foreign substances.
What is the function of Interferon beta (β)?
It slows inflammation in a damaged area.
What must C1 attach to for its activation in the classical pathway?
Two antibodies.
What are the two main types of immunity?
Innate immunity and adaptive immunity.
What type of MHC is involved in antigen recognition by CD4 T cells?
Class II MHC.
What types of cells are classified as fixed macrophages?
Monocytes and free macrophages.
What is active immunity?
Immunity that develops after exposure to antigens in the environment or through administration of an antigen.
Where are Class II MHC proteins produced?
In the endoplasmic reticulum.
Where are macrophages distributed in the body?
Throughout the body.
What is a sensitized B cell?
A B cell that has been activated and is ready to produce antibodies.
How does sweat help in defending the body?
It washes away pathogens.
What is the purpose of the clotting reaction during inflammation?
To wall off the region of injury or infection.
What is an antigen?
A substance that triggers an immune response.
What is the T cell receptor's role?
It recognizes specific antigens presented by Class II MHC molecules.
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.
What role do phagocytes play in the immune system?
They engulf and digest pathogens and debris.
What is the role of dendritic cells in immunity?
They present antigens to T cells, initiating immune responses.
What is one way the body prepares for future infections?
By remembering past infections.
What happens when antigens bind to antibody molecules?
It triggers a response from B cells, leading to their activation.
What are fixed macrophages also known as?
Histiocytes.
What is the function of Helper T cells in the immune system?
They promote B cell activation and division.
What is an inactive CD4 (T H) cell?
A T helper cell that has not yet been activated by an antigen.
What is naturally acquired passive immunity?
Immunity conferred by transfer of maternal antibodies across the placenta or in breast milk.
How do MHC proteins differ among individuals?
They vary genetically, leading to differences in antigen presentation.
What is the significance of increased regional temperature during inflammation?
It helps accelerate the healing process.
What happens during the activation of Helper T cells?
They become activated and can then promote the immune response.
What is required for T cell activation besides antigen recognition?
Costimulation.
What are Cytotoxic T cells also known as?
T C cells.
What is the function of Suppressor T Cells in the immune response?
To limit the immune reaction to a single stimulus.
What is the significance of C3b in the complement system?
It attaches to the bacterial cell wall.
What are MHC proteins?
Membrane glycoproteins that bind to antigens.
What does MHC stand for?
Major histocompatibility complex.
Where do free macrophages travel?
Throughout the body.
What type of immunity is associated with T cells recognizing antigens?
Cell-mediated immunity.
What is the function of the Golgi apparatus in NK cells?
The Golgi apparatus realigns to face the abnormal cell.
