Immune System Flashcards
Name the two systems explored in this chapter.
The lymphatic system and the lymphoid organs and tissues.
What is the function of the lymphatic system?
To return fluids that have leaked from the vascular system back to the blood.
What are the three parts of the lymphatic system?
Lymphatic vessels, lymph nodes, and MALT (mucosa-associated lymphoid tissue).
What is the anatomical basis for the body’s defenses?
Lymphoid organs and tissues.
What are some examples of lymphoid organs and tissues?
Lymph nodes, spleen, thymus, and MALT.
What is the function of lymph nodes?
To filter lymph and remove foreign substances, such as bacteria and cancer cells.
What is the function of the spleen?
To filter blood and remove old or damaged red blood cells.
What is MALT?
Mucosa-associated lymphoid tissue, which protects mucous membranes from pathogens.
What is the relationship between the lymphatic system and the immune system?
The lymphatic system supports the immune system by returning leaked fluids and providing a site for immune cell activation and proliferation.
What is the purpose of exploring the developmental aspects of the lymphatic system and lymphoid organs and tissues?
To understand how these systems develop and mature over time, and how they may be affected by disease or injury.
List the functions of the lymphatic vessels.
The lymphatic vessels collect excess protein-containing interstitial fluid and return it to the bloodstream, and also transport lymph, a clear water fluid, which contains immune cells and waste products.
Describe the structure and distribution of lymphatic vessels.
Lymphatic vessels form a one-way system in which lymph flows only toward the heart. The transport of lymph begins in microscopic blind-ended lymphatic capillaries that weave between the tissue cells and blood capillaries in the loose connective tissues of the body. Lymphatic capillaries are widespread, but they are absent from bones (including bone marrow) and teeth.
Describe the source of lymph and mechanism(s) of lymph transport.
Lymph is formed from the excess interstitial fluid that is collected by the lymphatic capillaries. The lymphatic vessels have valves that prevent backflow of lymph, and they are also aided by the contraction of surrounding skeletal muscles and respiratory movements to propel lymph towards the heart.
What is the function of the minivalves in lymphatic capillaries?
To allow fluid to enter the lymphatic capillary when fluid pressure in the interstitial space is greater than the pressure in the lymphatic capillary.
What happens when the pressure is greater inside the lymphatic capillary?
The endothelial minivalve flaps shut, preventing lymph from leaking back out as the pressure moves it along the vessel.
What kind of particles can enter lymphatic capillaries easily?
Proteins in the interstitial space and larger particles such as cell debris, pathogens, and cancer cells when tissues become inflamed.
What happens to the particles that enter lymphatic capillaries?
They travel with the lymph to the lymph nodes, where they are removed by cells of the immune system.
Why is the process of pathogens meeting up with immune cells in lymph nodes critical?
Because it allows for the removal of disease-causing microorganisms such as bacteria and viruses.
Where are lymphatic capillaries present in the central nervous system?
They are present but restricted to limited locations in the meninges, where they help drain the extracellular fluids in the brain.
What are the two unique structural modifications that make lymphatic capillaries permeable?
Loosely overlapping edges of adjacent endothelial cells forming easily opened, flaplike minivalves and collagen filaments anchoring the endothelial cells to surrounding structures.
What is the function of the thoracic duct?
To drain lymph from the rest of the body and empty it into the blood at the junction of the left internal jugular and subclavian veins.
What is the function of the right lymphatic duct?
To drain lymph from the right upper limb and the right side of the head and thorax, and empty it into the blood at the junction of the right internal jugular and subclavian veins.
What are the mechanisms that promote lymph flow in the lymphatic vessels?
The milking action of active skeletal muscles, pressure changes in the thorax during breathing, and valves to prevent backflow.
What is the function of smooth muscle in the walls of lymphatic vessels?
To contract rhythmically and help pump lymph along.
What is the importance of movement of adjacent tissues in lymph transport?
It is extremely important in propelling lymph through the lymphatics.
What is the function of lacteals in the lymphatic system?
To transport absorbed fat from the small intestine to the bloodstream.
What is chyle?
Fatty lymph that drains from the fingerlike villi of the intestinal mucosa.
What are the three tunics of collecting lymphatic vessels?
They have the same three tunics as veins.
What is the anatomical distribution of lymphatic vessels?
It varies greatly between individuals, even more than it does for veins.
What are the major lymphatic trunks?
The paired lumbar, bronchomediastinal, subclavian, and jugular trunks, and the single intestinal trunk.
What are the two large ducts that lymph is eventually delivered to in the thoracic region?
The right lymphatic duct and the much larger thoracic duct.
What is lymphangitis?
A condition where the pathway of the associated superficial lymphatics becomes visible through the skin as red streaks that are tender to the touch due to severe inflammation of lymphatic vessels.
What can prevent the normal return of lymph to the blood?
Tumors blocking the lymphatics or surgical removal of lymph nodes.
Name three types of cells that play a crucial role in body protection and immune response.
Macrophages, dendritic cells, and reticular cells.
What is the function of lymphoid tissue in the immune system?
It houses lymphocytes and provides a site where they can be activated and proliferate, and it furnishes an ideal surveillance vantage point for lymphocytes and macrophages.
What is reticular connective tissue, and what is its function in lymphoid organs and tissues?
Reticular connective tissue is a type of loose connective tissue that dominates all the lymphoid organs except the thymus. It produces the reticular fiber stroma, which is the network that supports the other cell types in lymphoid organs and tissues.
What is the function of lymphatic vessels?
Lymphatic vessels return excess tissue fluid to the blood, return leaked proteins to the blood, carry pathogens to lymph nodes, and carry absorbed fat from the intestine to the blood through lacteals.
What are the two main varieties of lymphocytes, and how do they protect the body against antigens?
The two main varieties of lymphocytes are T cells and B cells. Activated T cells manage the immune response, and some of them directly attack and destroy infected cells. Activated B cells protect the body by producing plasma cells, daughter cells that secrete antibodies into the blood or other body fluids. Antibodies mark antigens for destruction.
Where is diffuse lymphoid tissue found in the body?
In virtually every body organ, with larger collections appearing in the lamina propria of mucous membranes such as those lining the digestive tract.
What are lymphoid follicles and where are they found?
Solid, spherical bodies consisting of tightly packed lymphoid cells and reticular fibers, often with lighter-staining germinal centers where proliferating B cells predominate. They form part of larger lymphoid organs such as lymph nodes, but isolated aggregations occur in the intestinal wall as Peyer’s patches and in the appendix.
What are the primary lymphoid organs and where do B and T cells mature?
The red bone marrow and the thymus. While both B and T cells originate in the red bone marrow, B cells mature in the red bone marrow and T cells mature in the thymus.
What are the secondary lymphoid organs and what is their function?
They include the lymph nodes, the spleen, and the collections of mucosa-associated lymphoid tissue (MALT) that form the tonsils, Peyer’s patches in the small intestine, and the appendix. They are where mature lymphocytes first encounter their antigens and are activated.
What are the two protective functions of lymph nodes?
Cleansing the lymph by removing and destroying microorganisms and other debris that enter the lymph, and immune system activation by strategically located sites where lymphocytes encounter antigens and are activated to mount an attack against them.
What is the structure of a lymph node and how does it support its defensive functions?
Most lymph nodes are bean-shaped and less than 2.5 cm in length, surrounded by a dense fibrous capsule from which connective tissue strands called trabeculae extend inward to divide the node into a cortex and medulla. The structure supports its defensive functions by acting as a lymph filter and strategically located sites where lymphocytes encounter antigens and are activated to mount an attack against them.
What is the function of lymph nodes in the immune system?
To filter lymph and activate lymphocytes to mount an immune attack against foreign agents.
How does lymph circulate through a lymph node?
Lymph enters through afferent lymphatic vessels, moves through the subcapsular sinus and smaller sinuses in the cortex and medulla, and exits through efferent lymphatic vessels at the hilum.
What is the structure of a lymph node?
A lymph node has a capsule, trabeculae, cortex, medulla, lymphoid follicles, germinal centers, subcapsular sinus, medullary cords, and medullary sinuses.
What is the function of the cortex in a lymph node?
The cortex contains densely packed follicles, many with germinal centers heavy with dividing B cells, and primarily houses T cells in transit.
What is the function of the medulla in a lymph node?
The medulla consists of medullary cords and sinuses, and both B and T lymphocytes are found here.
What is the role of macrophages in lymph nodes?
Macrophages reside on reticular fibers in lymph sinuses and phagocytize foreign matter in the lymph as it flows by.
What happens when lymph nodes are overwhelmed by foreign agents?
They become inflamed.
What is the consequence of lymph stagnation in a lymph node?
It allows time for lymphocytes and macrophages to carry out their protective functions.
What is the histological difference between the cortex and medulla in a lymph node?
The cortex contains densely packed follicles and primarily houses T cells in transit, while the medulla consists of medullary cords and sinuses and both B and T lymphocytes are found here.
Where is the spleen located in the body?
In the left side of the abdominal cavity just beneath the diaphragm.
What is the size of the spleen?
About the size of a fist.
What is the function of the spleen?
It provides a site for lymphocyte proliferation and immune surveillance and response. It also extracts aged and defective blood cells and platelets from the blood, removes debris and foreign matter, and performs blood-cleansing functions.
What are the blood vessels that serve the spleen?
The large splenic artery and vein.
What is lymphadenopathy?
A condition where lymph nodes become swollen, tender, and infected.
What are buboes?
Infected lymph nodes that are often pus-filled.
What happens when cancer cells enter lymphatic vessels and become trapped in lymph nodes?
Lymph nodes can become secondary cancer sites, particularly when metastasizing cancer cells enter lymphatic vessels and become trapped there.
What is the benefit of having fewer efferent than afferent lymphatics in lymph nodes?
Having fewer efferent than afferent lymphatics in lymph nodes slows down the flow of lymph, allowing more time for immune cells to carry out their functions.
What is a lymphoid follicle?
A lymphoid follicle is a spherical mass of lymphoid tissue that is not surrounded by a connective tissue capsule. B cells predominate in follicles, especially in their germinal centers.
Define Peyer’s patches.
Peyer’s patches are large clusters of lymphoid follicles located in the wall of the distal portion of the small intestine.
What is the function of Peyer’s patches?
To trap bacteria and particulate matter and generate many ‘memory’ lymphocytes for long-term immunity.
What is the appendix?
The appendix is a tubular offshoot of the first part of the large intestine that contains a high concentration of lymphoid follicles.
What is the function of the appendix?
To prevent bacteria from breaching the intestinal wall and generate many ‘memory’ lymphocytes for long-term immunity.
What are tonsils?
Tonsils are a ring of lymphoid tissue around the entrance to the pharynx that gather and remove many of the pathogens entering the pharynx in food or inhaled air.
What are the different types of tonsils?
The different types of tonsils are palatine tonsils, lingual tonsil, pharyngeal tonsil, and tubal tonsils.
What is the function of the tonsils?
To gather and remove many of the pathogens entering the pharynx in food or inhaled air.
What are the characteristics of the lymphoid tissue in the tonsils?
The lymphoid tissue of the tonsils contains follicles with obvious germinal centers surrounded by diffusely scattered lymphocytes. The tonsils are not fully encapsulated, and the epithelium overlying them invaginates deep into their interior, forming blind-ended tonsillar crypts.
What is the function of the thymus?
The thymus functions as a maturation site for T lymphocyte precursors.
What is the blood thymus barrier?
The blood thymus barrier keeps bloodborne antigens out of the thymus.
What is the stroma of the thymus made of?
The stroma of the thymus consists of epithelial cells.
Where is the thymus located?
The thymus is found in the inferior neck and extends into the superior thorax.
What happens in the thymus?
T lymphocyte precursors mature to become immunocompetent lymphocytes in the thymus.
What happens to the thymus as we age?
The thymus gradually atrophies and is replaced almost entirely by fibrous and fatty tissue.
What are thymic corpuscles?
Thymic corpuscles are bizarre structures consisting of concentric whorls of keratinized epithelial cells that are involved in the development of regulatory T cells.
How does the thymus differ from secondary lymphoid organs?
The thymus has no follicles because it lacks B cells and it is the only primary lymphoid organ.
Name the major functions of lymph nodes.
Cleanse lymph and serve as a site for lymphocyte activation and proliferation.
What is the function of the spleen?
Cleanses blood, removes aged or defective red blood cells, serves as a site for lymphocyte activation and proliferation, and stores platelets, monocytes, and iron.
What is the function of MALT?
Prevent pathogens from penetrating mucous membrane and serve as a site for lymphocyte activation and proliferation.
What is the function of the thymus?
Site of T cell maturation.
What is elephantiasis?
A tropical disease in which the lymphatics become clogged with parasitic roundworms, causing swelling in the lower limbs and scrotum.
What is Hodgkin’s lymphoma?
A malignancy of lymphoid tissue characterized by swollen, nonpainful lymph nodes, fatigue, and often intermittent fever and night sweats. It is treated with chemotherapy and radiation and has a high cure rate.
What is lymphadenopathy?
Any disease of the lymph nodes.
What is lymphangiography?
A diagnostic procedure in which the lymphatic vessels are injected with radiopaque dye and then visualized with X rays.
What is lymphoma?
Any neoplasm (tumor) of the lymphoid tissue, whether benign or malignant.
What is non-Hodgkin’s lymphoma?
Includes all cancers of lymphoid tissues except Hodgkin’s lymphoma. It involves uncontrolled multiplication and metastasis of undifferentiated lymphocytes, with swelling of the lymph nodes, spleen, and Peyer’s patches other organs may eventually become involved.
What is a sentinel node?
The first node that receives lymph drainage from a body area suspected of being cancerous. When examined for presence of cancer cells, this node gives the best indication of whether metastasis through the lymphatic vessels has occurred.
What is splenomegaly?
Enlargement of the spleen, typically caused by accumulation of infectious microorganisms and may be due to septicemia, mononucleosis, malaria, or leukemia.
What is tonsillitis?
Inflammation of the tonsils, typically due to bacterial infection. Tonsils become red, swollen, and sore.
Which body system helps protect nervous system structures from specific pathogens?
Immune system.
What is the role of lymphatic vessels in the endocrine system?
They pick up leaked fluids and proteins.
How do stress hormones affect immune activity in the endocrine system?
They depress immune activity.
What is the role of the spleen in the cardiovascular system?
It removes and destroys aged RBCs and debris, and stores iron, platelets, and monocytes.
What is the function of lymphoid follicles in the intestinal wall in the digestive system?
They prevent invasion of pathogens.
How does the urinary system maintain homeostatic balances of water, pH, and electrolytes in the blood for lymphoid/immune cell functioning?
By eliminating wastes.
What is the role of lymphocytes in the integumentary system?
They enhance the skin’s protective role by defending against specific pathogens via the immune response.
What is the function of hematopoietic tissue in the skeletal system?
It produces the lymphocytes (and macrophages) that populate lymphoid organs and provide immunity.
How does the skeletal muscle ‘pump’ aid the flow of lymph in the muscular system?
It aids the flow of lymph.
What is the role of shivering in the muscular system?
It produces heat at the beginning of a fever.
Define lymph nodes.
Lymph nodes are the principal lymphoid organs that are clustered along lymphatic vessels. They filter lymph and help activate the immune system.
What are the components of a lymph node?
Each lymph node has a fibrous capsule, a cortex, and a medulla. The cortex contains mostly lymphocytes, which act in immune responses the medulla contains macrophages, which engulf and destroy viruses, bacteria, and other foreign debris, as well as lymphocytes.
How does lymph flow through the lymph nodes?
Lymph enters the lymph nodes via afferent lymphatic vessels and exits via efferent vessels. There are fewer efferent vessels therefore, lymph flow stagnates within the lymph node, allowing time for its cleansing.
What is the function of the spleen?
The spleen removes bloodborne pathogens and aged red blood cells, provides a site for lymphocyte proliferation and immune function, recycles the breakdown products of hemoglobin, stores platelets and monocytes, and may be a hematopoietic site in the fetus.
What is MALT?
MALT (mucosa-associated lymphoid tissue) is a collection of lymphoid tissues that guard the body’s entryways against pathogens. It includes Peyer’s patches of the intestinal wall, lymphoid follicles of the appendix, tonsils of the pharynx and oral cavity, and follicles in the genitourinary and respiratory tract mucosae.
What is the function of the thymus?
The thymus provides the environment in which T lymphocytes mature and become immunocompetent. The thymus is most functional during youth.
What is the lymphatic system?
The lymphatic system includes lymphatic vessels, lymph, and lymph nodes. Lymphatic vessels return fluids that have leaked from the blood vascular system back to the blood. Lymphoid organs and tissues protect the body by removing foreign material from the lymph and bloodstream, and provide a site for immune surveillance.
What are the primary lymphoid organs?
The primary lymphoid organs are the red bone marrow and thymus, which are sites where lymphocytes develop and mature.
What are the secondary lymphoid organs?
The secondary lymphoid organs include lymph nodes, the spleen, and MALT. They are sites where lymphocytes encounter their antigens and are activated.
What is the function of lymphoid tissue?
Lymphoid tissue is an important element of the immune system. It houses macrophages and a continuously changing population of lymphocytes. It may be diffuse or packaged into dense follicles, which often display germinal centers (areas where B cells are proliferating).
What is the immune system?
The body’s defense against disease-causing organisms and cancerous cells.
What are surface barriers?
The skin and mucosae that provide the first line of defense against pathogens.
What are innate internal defenses?
Cells and chemicals that provide a rapid, non-specific response to pathogens.
What are lymphocytes and antigen-presenting cells?
Specialized cells that play a key role in the adaptive immune response.
What is the humoral immune response?
The production of antibodies by B cells to neutralize pathogens in the body.
What is the cellular immune response?
The activation of T cells to directly attack and destroy infected cells.
What happens when things go wrong with the immune system?
Autoimmune diseases, allergies, and immunodeficiency disorders can occur.
What are the developmental aspects of the immune system?
The immune system develops and matures throughout childhood and adolescence.
Where can you find a video about the chapter content being used in a healthcare setting?
Mastering A&P® > Study Area > Animations and Videos or use quick access URL https://bit.ly/3P8hiZa
What is the immune system?
A functional system consisting of a diverse array of molecules and immune cells that inhabit lymphoid tissues and circulate in body fluids.
What are the innate and adaptive defenses?
The innate and adaptive defenses are deeply intertwined. The innate responses are not as nonspecific as once thought and have specific pathways to target certain foreign substances. Proteins released during innate responses alert cells of the adaptive system to the presence of specific foreign molecules in the body.
What is the role of the immune system?
To protect the body from most infectious microorganisms, cancer cells, and transplanted organs and grafts, both directly by cell attack and indirectly by releasing mobilizing chemicals and protective antibody molecules.
What are surface barriers?
The skin and mucous membranes, along with the secretions these membranes produce, that act as the body’s first line of defense to keep invaders out of the body.
What is the innate defense system?
The innate defense system is the body’s first line of defense consisting of surface barriers and internal defenses such as antimicrobial proteins, phagocytes, and other cells to inhibit the invaders’ spread throughout the body.
What is the adaptive defense system?
The adaptive defense system functions like an elite fighting force equipped with high-tech weapons to attack identified foreign substances and takes considerably longer to mount than the innate defense response.
What is the hallmark of the second line of defense?
Inflammation.
What is the difference between humoral immunity and cellular immunity?
Humoral immunity primarily involves B lymphocytes, while cellular immunity involves T lymphocytes. Both are distinct but overlapping areas of adaptive immunity.
Name some innate internal defenses of the body.
Phagocytes, natural killer cells, antimicrobial proteins, and fever.
What is the inflammatory response and what are its components?
The inflammatory response is a protective response that enlists macrophages, mast cells, all types of white blood cells, and dozens of chemicals that kill pathogens and help repair tissue.
What are pattern recognition receptors and what is their role in immune responses?
Pattern recognition receptors are receptors that identify potentially harmful substances by recognizing molecules with specific shapes that are part of infectious organisms but not normal human cells. Toll-like receptors (TLRs) are a class of pattern recognition receptors that play a central role in triggering immune responses.
What are the body’s antimicrobial substances and what are their functions?
The body’s antimicrobial substances include acid, enzymes, mucin, defensins, and other chemicals. They function to inhibit bacterial growth, destroy bacteria, trap microorganisms, and control bacterial and fungal colonization in exposed areas.
What are the surface barriers of the body and how do they protect against pathogens?
The surface barriers of the body include intact skin epidermis, intact mucous membranes, nasal hairs, cilia, gastric juice, acid mantle of vagina, lacrimal secretion, saliva, and urine. They protect against pathogens by forming mechanical barriers, trapping microorganisms, inhibiting bacterial growth, and destroying pathogens.
What is the first line of defense against disease?
The surface membrane barriers are the first line of defense against disease.
What are TLRs and what is their function?
TLRs are pattern recognition receptors found on various cells, including macrophages and epithelial cells, that allow the cells to recognize invaders and initiate inflammation.
What are phagocytes and how do they work?
Phagocytes are cells that engulf and digest particulate matter, such as pathogens. Neutrophils and macrophages are types of phagocytes. They use receptors to bind to the particle and pull it inside, enclosed within a membrane-lined vesicle. The resulting phagosome then fuses with a lysosome to form a phagolysosome, which is then destroyed by lysosomal enzymes and other protein-digesting enzymes.
What is opsonization and how does it help phagocytosis?
Opsonization is the process of coating pathogens with opsonins, such as complement proteins or antibodies, which provide ‘handles’ to which phagocyte receptors can bind. This greatly accelerates phagocytosis of the pathogen.
What is the respiratory burst and how does it promote killing of pathogens?
The respiratory burst is a process in which neutrophils and macrophages release a deluge of highly destructive free radicals, oxidizing chemicals, and other substances that increase the phagolysosome’s pH and osmolarity. This activates other protein-digesting enzymes that digest the invader and promotes killing of pathogens.
What are defensins and how do they work?
Defensins are antimicrobial peptides that neutrophils use to pierce the pathogen’s membrane. They disrupt the membrane’s integrity and cause the pathogen to leak and die.
What are phagocytes and how do they kill their targets?
Phagocytes are defensive cells that ingest and destroy their targets. When they are unable to ingest their targets, they can release their toxic chemicals into the extracellular fluid. Neutrophils rapidly destroy themselves in the process, while macrophages are more robust and can survive to kill another day.
What are natural killer (NK) cells and how do they kill their targets?
Natural killer (NK) cells are a unique group of defensive cells that can kill cancer cells and virus-infected body cells before the adaptive immune system is activated. Unlike lymphocytes of the adaptive immune system, which only recognize and react against specific infected or tumor cells, NK cells are far less picky. They can eliminate a variety of infected or cancerous cells by detecting general abnormalities such as the lack of “self” cell-surface proteins called MHC. NK cells kill by directly contacting the target cell, inducing it to undergo apoptosis (programmed cell death).
What is inflammation and what are its beneficial effects?
Inflammation is a nonspecific response to any tissue injury caused by physical trauma, intense heat, irritating chemicals, or infection. Its beneficial effects include preventing the spread of damaging agents to nearby tissues, disposing of cell debris and pathogens, alerting the adaptive immune system, and setting the stage for repair.
What are the four cardinal signs of acute inflammation?
The four cardinal signs of acute inflammation are redness, heat, swelling, and pain. Impaired function may also be considered a fifth cardinal sign.
What are inflammatory chemicals and how do they contribute to the inflammatory process?
Inflammatory chemicals are released by injured or stressed tissue cells and immune cells. They can also be formed from chemicals circulating in the blood. Inflammatory chemicals dilate local arterioles, make local capillaries leakier, attract phagocytes to the injured area, and mobilize lymphocytes and other elements of adaptive immunity. They include histamine, kinins, prostaglandins, cytokines, and complement.
What is vasodilation and how does it contribute to inflammation?
Vasodilation of local arterioles causes local hyperemia, which brings more cells and chemicals of the immune system to the injured area. It accounts for the redness and heat of an inflamed region.
What is increased vascular permeability and how does it contribute to inflammation?
Inflammatory chemicals increase the permeability of local capillaries and venules, causing exudate to seep from the blood vessels into the surrounding tissue. Exudate contains clotting factors and antibodies and helps dispose of cell debris and pathogens. It also promotes the formation of edema, which contributes to the swelling of an inflamed region.
What are the four cardinal signs of acute inflammation?
Heat, redness, pain, and swelling.
What is the initial stimulus for acute inflammation?
Tissue injury.
What are the physiological responses to tissue injury?
Release of inflammatory chemicals, dilation of arterioles, increased capillary permeability, and local hyperemia.
What is leukocytosis?
Increased numbers of white blood cells in the bloodstream.
What is the purpose of leukocytes in acute inflammation?
To migrate to the injured area, cling to capillary walls, and pass through capillary walls to perform phagocytosis of pathogens and dead tissue cells.
What is the possible result of an abscess formed during acute inflammation?
It may need to be surgically drained before healing can occur.
What are granulomas?
Tumorlike growths that contain a central region of infected macrophages surrounded by uninfected macrophages and an outer fibrous capsule.
What is the potential danger of harboring pathogens walled off in granulomas?
If a person’s resistance to infection is ever compromised, the bacteria may be activated and break free, leading to clinical disease symptoms.
What are interferons and how do they protect against viruses?
Interferons are immune modulating proteins produced by body cells that block further protein synthesis and degrade viral RNA, thus interfering with viral replication. They diffuse to nearby cells and stimulate them to synthesize proteins that block viral replication. IFNs produced against a particular virus protect against other viruses too.
What are the different types of interferons and what are their physiological effects?
The different types of interferons are IFN alpha (α), beta (β), and gamma (γ). IFN alpha and beta have antiviral effects and activate NK cells. IFN gamma is secreted by lymphocytes and has widespread immune mobilizing effects, such as activating macrophages.
What is the complement system and how does it destroy foreign substances in the body?
The complement system is a group of at least 20 plasma proteins that normally circulate in the blood in an inactive state. Its activation unleashes inflammatory chemicals that amplify virtually all aspects of the inflammatory process. Activated complement also lyses and kills certain bacteria and other cell types. Complement activation by any of the three pathways involves a cascade in which proteins are activated in an orderly sequence, each step catalyzing the next. The three pathways converge at C3, which is split into C3a and C3b. Splitting C3 initiates a common terminal pathway that enhances inflammation, promotes phagocytosis, and can cause cell lysis.
What are the three pathways by which complement can be activated?
The three pathways by which complement can be activated are the classical pathway, the lectin pathway, and the alternative pathway.
What are antimicrobial proteins and how do they enhance our innate defenses?
Antimicrobial proteins are proteins that attack microorganisms directly or hinder their ability to reproduce. They enhance our innate defenses by providing a nonspecific defense mechanism that complements the effectiveness of both innate and adaptive defenses. The most important antimicrobial proteins are interferons and complement proteins.
What is fever and how does it benefit the body?
Fever is an abnormally high body temperature that is a systemic response to invading microorganisms. It benefits the body by causing the liver and spleen to sequester iron and zinc, which may make them less available to support bacterial growth. Additionally, fever increases the metabolic rate of tissue cells and may speed up repair processes.
What are pyrogens and how do they cause fever?
Pyrogens are chemicals released by leukocytes and macrophages when exposed to foreign substances in the body. They act on the body’s thermostat, raising the body’s temperature above normal.
What is cell lysis and how does it occur?
Cell lysis is the destruction of a cell’s membrane, which leads to the release of its contents. It occurs when C3b binds to the target cell’s surface and triggers the insertion of a group of complement proteins called MAC (membrane attack complex) into the cell’s membrane. MAC forms and stabilizes a hole in the membrane that allows a massive influx of water, lysing the target cell.
What is opsonization and how does it help phagocytes?
Opsonization is the process by which complement proteins, such as C3b, coat the surface of a microorganism, providing ‘handles’ that receptors on macrophages and neutrophils can adhere to. This allows them to engulf the particle more rapidly. An example of a molecule that acts as an opsonin is C3b.
Under what circumstances might NK cells kill our own cells?
NK cells might kill our own cells under circumstances where the cells are infected with a virus or have become cancerous, as these cells may display abnormal surface proteins that trigger the NK cells’ response.
What is humoral immunity?
Humoral immunity, also called antibody-mediated immunity, is provided by antibodies present in the body’s fluids (blood, lymph, etc.).
What is cellular immunity?
Cellular immunity, also called cell-mediated immunity, is when living cells (lymphocytes) provide protection against pathogens, cancer cells, and cells of foreign grafts.
What is the difference between humoral and cellular immunity?
Humoral immunity uses antibodies present in the body’s fluids, while cellular immunity uses living cells (lymphocytes) to provide protection.
What are the cardinal signs of inflammation?
The cardinal signs of inflammation are redness, heat, swelling, and pain.
What causes the cardinal signs of inflammation?
The cardinal signs of inflammation are caused by increased blood flow and permeability of blood vessels in the affected area.
What is the body’s third line of defense?
The adaptive immune system is the body’s third line of defense.
What is the major shortcoming of the adaptive immune system?
The major shortcoming of the adaptive immune system is that it must be primed by an initial exposure to a specific foreign substance (antigen) before it can protect the body against that substance.
What devastating diseases can result from the failure or disablement of the adaptive immune system?
Devastating diseases such as cancer and AIDS can result from the failure or disablement of the adaptive immune system.
What did experiments in the late 1800s reveal about specific immunity?
Experiments in the late 1800s revealed that animals surviving a serious bacterial infection have protective factors (the proteins we now call antibodies) in their blood that defend against future attacks by the same pathogen.
Define antigen.
Substances that can mobilize the adaptive defenses and are the ultimate targets of all adaptive immune responses.
What is the difference between complete antigens and haptens?
Complete antigens have immunogenicity and reactivity, while haptens have reactivity but not immunogenicity.
What are antigenic determinants?
Certain parts of an antigen that are immunogenic and antibodies or lymphocyte receptors bind to these antigenic determinants.
What are MHC proteins?
A group of glycoproteins that identify a cell as self and are strongly antigenic to other individuals.
What are the four key characteristics of the adaptive immune response?
It involves B and T lymphocytes, is specific, systemic, and has memory.
What is the difference between naturally occurring antigens and large simple molecules?
Naturally occurring antigens have a variety of antigenic determinants on their surfaces, while large simple molecules have little or no immunogenicity.
What are some examples of chemicals that act as haptens?
Certain drugs (particularly penicillin), poison ivy, animal dander, detergents, cosmetics, and a number of common household and industrial products.
Why are large proteins highly immunogenic and reactive?
They have hundreds of chemically different antigenic determinants on their surfaces.
What is the basis of transfusion reactions and graft rejection?
Self-antigens are strongly antigenic to other individuals.
What is the meaning of the term ‘antigen’?
A contraction of ‘antibody generating’ and refers to substances that can mobilize the adaptive defenses.
Define immunocompetence.
The ability of a lymphocyte to recognize and bind to a specific antigen.
What is self-tolerance?
The relative unresponsiveness of a lymphocyte to self-antigens to prevent attacking the body’s own cells.
What are primary lymphoid organs?
The lymphoid organs where lymphocytes mature, such as the thymus and red bone marrow.
What are secondary lymphoid organs?
All other lymphoid organs, such as lymph nodes and spleen, where immunocompetent B and T cells seed and encounter antigens.
What is the function of antigen-presenting cells (APCs)?
APCs play essential auxiliary roles in the adaptive immune response and are required for T cells to recognize their antigens.
What are the two distinct populations of lymphocytes involved in the adaptive immune response?
B lymphocytes (B cells) and T lymphocytes (T cells).
What is the difference between B cells and T cells?
B cells oversee humoral immunity and produce antibodies, while T cells constitute the cellular arm of adaptive immunity and do not produce antibodies.
What are the five general steps in the development, maturation, and activation of B and T cells?
Origin, maturation, immunocompetence, self-tolerance, and seeding secondary lymphoid organs and circulation.
What is clonal selection?
The process by which an antigen selects a particular immunocompetent lymphocyte for further development and activation.
What are homing signals (CAMs)?
Signals displayed on vascular endothelial cells that regulate lymphocyte movement into the tissues.
What determines which foreign substances our immune system can recognize and resist?
Our genes, not antigens we encounter.
What represents our genetically acquired knowledge of the microbes that are likely to be in our environment?
The immune cell receptors.
What determines which existing T or B cells will proliferate and mount the attack against an antigen?
The antigen itself.
What is a clone in the context of lymphocyte proliferation and differentiation?
An army of identical cells, all descended from the same ancestor cell.
What are effector cells in the context of lymphocyte proliferation and differentiation?
The cells that actually do the work of fighting infection.
What are memory cells in the context of lymphocyte proliferation and differentiation?
Cells that are able to respond quickly after any subsequent encounter with the same antigen.
Where do B cells mature?
In the bone marrow.
Where do lymphocyte precursors destined to become T cells migrate to and mature?
To the thymus.
What happens when a lymphocyte’s antigen receptors bind its antigen?
That lymphocyte can be activated.
What are the primary lymphoid organs involved in lymphocyte development and maturation?
Red bone marrow and thymus.
What are the secondary lymphoid organs involved in antigen encounter and activation?
Lymph nodes, spleen, etc.
What are the two types of adaptive defenses?
Humoral immunity and cellular immunity.
What are dendritic cells and where are they found?
Dendritic cells are mobile sentinels found at the body’s frontiers, such as the skin, and are efficient antigen catchers.
What is the most important way of ensuring that lymphocytes encounter invading antigens?
Migration of dendritic cells to secondary lymphoid organs.
What is the job of dendritic cells?
Dendritic cells are the most effective antigen presenter known.
How do lymphocytes generate a seemingly limitless number of different antigen receptors?
Through a process called somatic recombination, where gene segments are shuffled and combined in different ways.
What is the selection process that lymphocytes undergo during maturation?
The selection process consists of positive and negative selection in the thymus.
What is positive selection in T cell education?
Positive selection ensures that only T cells with receptors that are able to recognize self-MHC proteins survive.
What is negative selection in T cell education?
Negative selection ensures that T cells do not recognize self-antigens displayed on self-MHC, and eliminates self-reactive lymphocytes.
What are antigen-presenting cells (APCs) and what is their role?
Antigen-presenting cells engulf antigens and present fragments of them on their own surfaces where T cells can recognize them, and are necessary for the activation of naive T cells.
Define B lymphocytes.
B lymphocytes are a type of white blood cell that present antigens to helper T cells in order to obtain help in their own activation.
What is the role of dendritic cells in the immune system?
Dendritic cells are one of the key links between innate and adaptive immunity. They initiate adaptive immune responses tailored to the type of pathogen they have encountered.
What is the role of macrophages in the immune system?
Macrophages are widely distributed throughout the lymphoid organs and connective tissues. They can activate naive T cells and present antigens to T cells to maintain T cell activation or to be activated themselves. Activated macrophages are true killers that trigger powerful inflammatory responses and recruit additional defenses.
What is the difference between humoral and cellular immune responses?
Humoral immune response involves B lymphocytes and antibody secretion, while cellular immune response involves T lymphocytes and cytotoxic T cells.
What is clonal selection?
Clonal selection is the process by which a specific antigen selectively activates only those lymphocytes bearing receptors specific for that antigen, leading to the proliferation and differentiation of those lymphocytes into a clone of effector cells and memory cells.
What is the role of APCs in T lymphocyte activation?
APCs, such as dendritic cells and macrophages, present antigens to T cells to activate them.
What is the site of origin and maturation for B and T lymphocytes?
Both B and T lymphocytes originate in the red bone marrow, but B cells mature in the red bone marrow while T cells mature in the thymus.
What is the role of helper T cells in the immune system?
Helper T cells coordinate both B and T lymphocyte responses.
What is the purpose of the adaptive immune system?
The adaptive immune system uses lymphocytes, APCs, and specific molecules to identify and destroy all substances that are in the body but not recognized as self.
What are the major similarities and differences between B and T lymphocytes?
Table 21.4 outlines major similarities and differences between B and T lymphocytes.
What is the process of clonal selection in B cells?
When a matching antigen binds to the surface receptors of a naive B lymphocyte, it is activated and undergoes clonal selection, followed by proliferation and differentiation into effector cells.
What are the effector cells of the humoral response?
Plasma cells are the effector cells of the humoral response.
What is the function of plasma cells in humoral immunity?
Plasma cells secrete antibodies at a high rate to target extracellular antigens.
How long do plasma cells function at a breakneck pace before dying?
Plasma cells function at a breakneck pace for 4 to 5 days before dying.
What is the role of memory cells in humoral immunity?
Memory cells are primed to respond to the same antigen in a secondary response, resulting in a larger and more rapid response.
What is humoral immunity?
Humoral immunity is a type of adaptive defense in which antibodies specific to an antigen are produced.
What is the structure and function of antibodies?
Antibodies are proteins that bind to specific antigens and mark them for destruction by other immune cells.
What are the five classes of antibodies?
The five classes of antibodies are IgM, IgG, IgA, IgD, and IgE.
Define primary immune response.
The primary immune response occurs on first exposure to a particular antigen and typically has a lag period of 3 to 6 days after the antigen encounter. It mirrors the time required for the few B cells specific for that antigen to proliferate and for their offspring to differentiate into plasma cells.
What is the difference between primary and secondary immune response?
Secondary immune responses are faster, more prolonged, and more effective, because the immune system has already been primed to the antigen, and sensitized memory cells are already ‘on alert’. These memory cells provide immunological memory.
What is active humoral immunity?
Active humoral immunity is acquired when B cells encounter antigens and produce antibodies against them. It is either naturally acquired when you get a bacterial or viral infection, or artificially acquired when you receive a vaccine.
What are the benefits of vaccines?
Vaccines provide weakened antigens that are both immunogenic and reactive. They spare us most of the symptoms and discomfort of the disease that would otherwise occur during the primary response.
What is passive humoral immunity?
Passive humoral immunity is acquired when antibodies are passed from mother to fetus via placenta or to infant in her milk, or through injection of exogenous antibodies (gamma globulin). It does not establish immunological memory.
Name three diseases for which antitoxin is used.
Botulism, rabies, and tetanus.
What is the biggest shortcoming of conventional vaccines?
They are not always as effective or long-lasting as we would like.
What is passive humoral immunity?
It is the introduction of ready-made antibodies into the body.
How is passive immunity conferred naturally on a fetus or infant?
When the mother’s antibodies cross the placenta or are ingested with the mother’s milk.
What is the difference between passive and active immunity?
Passive immunity involves the introduction of ready-made antibodies into the body, while active immunity involves the production of antibodies by the body’s own plasma cells.
What is the role of exogenous antibodies in passive immunity?
They are administered to prevent or treat diseases such as hepatitis A and poisonous snake bites.
What did Susumu Tonegawa discover about adaptive immunity?
He discovered that the regions of DNA that produce antibodies become greatly rearranged as the B cell matures, which is how a small number of antibody-producing genes generate the huge variety of antibodies seen.
What is the global status of access to vaccines for both children and adults?
Access to vaccines remains regrettably unequal both for children and adults globally.
What is the average number of deaths per year due to infectious diseases?
Almost six million deaths per year.
Define antibodies.
Antibodies are proteins secreted in response to an antigen by effector B cells called plasma cells, and the antibodies bind specifically with that antigen.
What is the basic structure of an antibody?
Each antibody consists of four looping polypeptide chains linked together by disulfide bonds, forming a molecule called an antibody monomer with two identical halves. The molecule as a whole is T or Y shaped.
What are the two types of chains that form an antibody?
The two types of chains that form an antibody are the heavy (H) chains and the light (L) chains.
What is the difference between the V and C regions of an antibody?
Each chain forming an antibody has a variable (V) region at one end and a constant (C) region at the other end. Antibodies responding to different antigens have very different V regions, but their C regions are the same (or nearly so) in all antibodies of a given class.
What are the five major immunoglobulin classes?
The five major immunoglobulin classes are IgM, IgA, IgD, IgG, and IgE.
What is the main function of IgM?
The main function of IgM is to serve as an antigen receptor on the B cell surface and to activate complement.
What is the most abundant antibody in plasma?
The most abundant antibody in plasma is IgG, accounting for 75-85% of circulating antibodies.
What is the function of IgE?
The stem end of IgE binds to mast cells or basophils, and antigen binding to its receptor end triggers these cells to release histamine and other chemicals that mediate inflammation and an allergic reaction.
What is the difference between secretory IgA and IgA monomer?
Secretory IgA, which is a dimer, is found in body secretions such as saliva, sweat, intestinal juice, and milk, and helps stop pathogens from attaching to epithelial cell surfaces. IgA monomer exists in limited amounts in plasma.
Define agglutination.
Agglutination is the clumping of foreign cells caused by cross-linking of antigen-antibody complexes.
What is the role of IgM in agglutination?
IgM is an especially potent agglutinating agent due to its 10 antigen-binding sites.
What is precipitation in the context of immune response?
Precipitation is the cross-linking of soluble molecules into large complexes that settle out of solution.
What is the chief antibody defense used against cellular antigens?
Complement activation is the chief antibody defense used against cellular antigens, such as bacteria or mismatched red blood cells.
What is neutralization in the context of immune response?
Neutralization is the blocking of specific sites on viruses or bacterial exotoxins by antibodies, preventing them from binding to receptors on tissue cells.
What are the defensive mechanisms used by antibodies?
The defensive mechanisms used by antibodies include neutralization, agglutination, precipitation, and complement activation.
What is the common event in all antibody-antigen interactions?
The common event in all antibody-antigen interactions is the formation of antigen-antibody (or immune) complexes.
What is the role of antibodies in immune response?
Antibodies inactivate antigens and tag them for destruction, and their defensive mechanisms include neutralization, agglutination, precipitation, and complement activation.
Can antibodies act intracellularly?
Yes, antibodies can act intracellularly as well.
What happens when antibodies are attached to a virus before it infects a cell?
The antibodies can ‘hang on’ to the virus as it slips inside the cell and activate intracellular mechanisms that destroy the virus.
Are antibodies effective against intracellular pathogens like viruses and tuberculosis bacilli?
No, antibodies are not very effective against intracellular pathogens.
What comes into play for intracellular pathogens?
The cellular arm of adaptive immunity comes into play for intracellular pathogens.
What are monoclonal antibodies?
Monoclonal antibodies are pure antibody preparations specific for a single antigenic determinant.
What are the uses of monoclonal antibodies?
Monoclonal antibodies are used in research, clinical testing, and treatment. They are used to diagnose pregnancy, certain sexually transmitted infections, some cancers, hepatitis, and rabies. They are also used to treat leukemia and lymphomas, cancers that are present in the circulation and to treat certain autoimmune diseases.
What is the role of antibodies in the destruction of parasitic worms?
IgE antibodies coat the surface of parasitic worms, marking them for destruction by eosinophils. When eosinophils encounter antibody-coated worms, they bind to the exposed stems of the IgE, which triggers the eosinophils to release the toxic contents of their large cytoplasmic granules all over their prey.
What is cellular immunity?
Cellular immunity consists of T lymphocytes that direct adaptive immunity or attack cellular targets.
What are the roles of T cells?
Some activated T cells directly kill body cells that are infected by viruses or bacteria, cancerous or abnormal, or foreign cells (e.g., transplanted cells). Other T cells release chemicals that regulate the immune response.
What are the two major populations of T cells based on?
The two major populations of T cells are based on which of two structurally related cell differentiation glycoproteins—CD4 or CD8—a mature T cell displays.
What are the surface receptors of T cells?
The surface receptors of T cells are CD4 and CD8 glycoproteins.
What are memory T cells?
Activated CD4 and CD8 cells that can remember previous infections and respond more quickly to future infections.
What is the role of MHC proteins in antigen presentation?
MHC proteins display processed fragments of protein antigens on the surface of body cells for recognition by T cells.
What is the difference between naive T cells and activated T cells in terms of naming?
Activated T cells are named after their effector function (helper, cytotoxic, regulatory), while naive T cells are simply called CD4 or CD8 cells.
What is the role of CD4 cells in cellular immunity?
CD4 cells usually become helper T cells that help activate B cells, other T cells, and macrophages, and direct the adaptive immune response.
What is the role of CD8 cells in cellular immunity?
CD8 cells become cytotoxic T cells that destroy cells in the body that harbor anything foreign.
What are regulatory T cells?
Regulatory T cells (TReg) moderate the immune response.
What is antigen presentation?
Antigen presentation is the process of displaying processed fragments of protein antigens on the surface of body cells for recognition by T cells.
What is required for both activation of naive T cells and the normal functioning of effector T cells?
Antigen presentation is necessary for both activation of naive T cells and the normal functioning of effector T cells.
What is the role of APCs in antigen presentation?
APCs (antigen-presenting cells) are responsible for presenting processed fragments of protein antigens on their surface for recognition by T cells.
What is the function of memory T cells?
Memory T cells can remember previous infections and respond more quickly to future infections.
What are MHC proteins?
Cell surface proteins on which antigens are presented to T cells.
What are the two classes of MHC proteins?
Class I and Class II.
Where are Class I MHC proteins found?
On the surface of virtually all body cells except red blood cells.
What is the function of Class I MHC proteins?
To hold an antigen, which is generally a protein fragment of 8 or 9 amino acids, and present it to cytotoxic T cells.
What are endogenous antigens?
Fragments of proteins synthesized inside the cell.
What are exogenous antigens?
Antigens from outside the cell that have been engulfed by the cell that displays them.
Where are Class II MHC proteins found?
On the surfaces of cells that present antigens to CD4 cells, such as dendritic cells, macrophages, and B cells.
What is the function of Class II MHC proteins?
To display foreign antigens to CD4 cells and signal that help is required.
How are antigens presented on Class I MHC proteins?
As proteases degrade cytoplasmic proteins, a random sample of the resulting protein fragments is transported into the endoplasmic reticulum. Inside the ER, these peptides bind to newly synthesized Class I MHC proteins. Transport vesicles then export the ‘loaded’ Class I MHC proteins to the cell surface.
How are antigens presented on Class II MHC proteins?
Exogenous antigens are broken down by proteases inside a phagolysosome. Vesicles from the ER containing Class II MHC proteins fuse with the phagolysosome, and the antigen fragments bind to the groove of the MHC proteins. The vesicle is then exported to the cell surface, where the Class II MHC protein displays its prize for CD4 cells to recognize.
What is the two-signal sequence in T cell activation?
It is a double-handshake process that involves antigen binding and co-stimulation.
What happens if a T cell binds to antigen without receiving the co-stimulatory signal?
The T cell becomes tolerant to that antigen and is unable to respond, which is called anergy.
What is MHC restriction?
It is the constraint that CD4 and CD8 cells have for the class of MHC protein that presents antigens to them, acquired during the education process in the thymus.
What is the difference in MHC restriction between CD4 and CD8 cells?
CD4 cells are restricted to binding antigens only on class II MHC proteins, while CD8 cells are activated by antigen fragments on class I MHC proteins.
How do dendritic cells obtain other cells’ endogenous antigens to display them on class I and class II MHCs?
They obtain other cells’ endogenous antigens either by engulfing dying virus-infected or tumor cells, or by importing antigens through temporary gap junctions with infected cells.
What is the role of co-stimulatory molecules in T cell activation?
Co-stimulatory molecules bind to specific receptors on a T cell and provide a crucial co-stimulatory signal along with antigen binding for T cell activation.
What is clonal selection in T cell activation?
It is the process of selecting and activating T cells that recognize and respond to a specific antigen-MHC complex on the surface of an APC, which requires both antigen binding and co-stimulation.
What is the difference between CD4 and CD8 proteins in T cell activation?
CD4 and CD8 proteins are adhesion molecules that help bind cells together during antigen recognition, and CD4 proteins are specific to helper T cells while CD8 proteins are specific to cytotoxic T cells.
What are cytokines and what is their role in the immune system?
Cytokines are hormone-like or paracrine-like glycoproteins released by a variety of cells that influence cell development, differentiation, and responses in the immune system. They include interferons and interleukins and have myriad effects on target cells, such as promoting T cell proliferation and amplifying and regulating adaptive and innate immune responses.
What is the role of interleukin 2 (IL-2) in the immune system?
IL-2 is a key growth factor that stimulates T cells to liberate more IL-2 and to synthesize more IL-2 receptors. Acting on the cells that release it (as well as other T cells), it sets up a positive feedback cycle that encourages activated T cells to divide even more rapidly.
What are the three major groups of effector T cells?
The three major groups of effector T cells are helper, cytotoxic, and regulatory T cells.
What happens to activated T cells after antigen binding and co-stimulation?
Once activated, T cells enlarge and proliferate, and cytokines released by APCs or T cells themselves promote this process. Cells of the resulting clone differentiate to perform functions according to their T cell class. This primary response peaks within a week of exposure to the triggering antigen. A period of apoptosis then occurs between days 7 and 30, during which time the activated T cells die off and effector activity wanes as the amount of antigen declines.
What is the role of memory T cells in the immune system?
Memory T cells persist perhaps for life, providing a reservoir of T cells that can later mediate secondary responses to the same antigen.
What are some examples of cytokines and their functions in the immune response?
Interferons (IFNs) have antiviral effects and activate NK cells. Interleukin 1 (IL-1) promotes inflammation and T cell activation, and causes fever. IL-2 stimulates T and B cell proliferation, TReg cell development, and NK cell activation. IL-4 promotes differentiation to TH2, promotes B cell activation, and switches antibody production to IgE. IL-5 attracts and activates eosinophils and causes plasma cells to secrete IgA antibodies. IL-10 inhibits macrophages and dendritic cells, turning down cellular and innate immune response. IL-12 stimulates TC and NK cell activity and promotes TH1 differentiation. IL-17 is important in innate and adaptive immunity and recruiting neutrophils, and is involved in inflammation in many autoimmune diseases. Tumor necrosis factors (TNFs) promote inflammation, enhance phagocyte chemotaxis and nonspecific killing, slow tumor growth by selectively damaging tumor blood vessels, and promote cell death by apoptosis. Transforming growth factor beta (TGF-β) is a suppressor factor similar to IL-10 that stimulates TReg and TH17 cell development.
Name two ways in which TH cells amplify the immune response.
TH cells activate macrophages to become more potent killers and release cytokines that mobilize lymphocytes and other white blood cells into the area.
What is the role of TH cells in adaptive immunity?
TH cells play a central role in adaptive immunity by mobilizing both its humoral and cellular arms. They help activate B and T cells, induce B and T cells to proliferate, and furnish the chemical help needed to recruit other immune cells.
What are the subsets of TH cells and what are their functions?
TH1 cells stimulate inflammation, activate macrophages, and promote differentiation of cytotoxic T cells. TH2 cells mainly defend against parasitic worms, activate immune responses that depend on B cells and antibody formation, and promote allergies. TH17 cells link together adaptive and innate immunity by releasing IL-17, which promotes inflammatory responses against extracellular microbes and may underlie most autoimmune diseases.
What happens when TH cells are destroyed, as in AIDS?
Without the help of TH cells, there is no adaptive immune response, and the immune system is severely compromised.
How do TH cells activate B cells?
TH cells interact directly with B cells displaying antigen fragments bound to class II MHC receptors. Whenever a TH cell binds to a B cell, the TH cell releases cytokines that prod the B cells into dividing more rapidly and signals for antibody formation to begin.
What is the difference between T cell–independent and T cell–dependent antigens?
T cell–independent antigens tend to be weak and short-lived, while T cell–dependent antigens require T cell help to activate the B cells to which they bind.
How do TH cells help activate CD8 cells?
TH cells cause dendritic cells to express on their surfaces the co-stimulatory molecules required to activate CD8 cells and produce interleukin 2, which causes the CD8 cell to proliferate and differentiate into a TC cell.
What are NK cells and how do they differ from TC cells?
NK cells are immune cells that search for signs of abnormality in cells, such as the lack of class I MHC or the presence of antibodies coating the target cell. They do not look for foreign antigens displayed on class I MHC proteins like TC cells do.
What is immune surveillance?
Immune surveillance is the process by which immune cells, such as NK cells and TC cells, roam the body and examine other cells for markers they might recognize.
What are regulatory T cells and what is their role in the immune response?
Regulatory T cells are T cells that dampen the immune response by suppressing self-reactive lymphocytes. They act either by direct contact or by releasing inhibitory cytokines. They are important in preventing autoimmune reactions.
What are cytotoxic T cells and what is their main target?
Cytotoxic T cells are T cells that can directly attack and kill other cells. Their main targets are virus-infected cells, but they also attack tissue cells infected by certain intracellular bacteria or parasites, cancer cells, and foreign cells introduced into the body by blood transfusions or organ transplants.
How do cytotoxic T cells deliver a lethal hit to their target cells?
Cytotoxic T cells deliver a lethal hit to their target cells through two major mechanisms: perforins and granzymes, which form transmembrane pores and activate enzymes that trigger apoptosis, or by binding to a specific membrane receptor on the target cell that stimulates the target cell to undergo apoptosis.
What do virus-infected cells release to warn nearby uninfected cells?
Interferon.
What is the role of phagocytes in the immune response to viruses?
To engulf viruses and release inflammatory chemicals to sound the alarm.
How does inflammation help in the immune response to viruses?
It brings more immune cells and plasma proteins to the area by dilating arterioles and increasing capillary permeability.
What is the role of complement activation in the immune response to viruses?
It enhances inflammation and causes opsonization of virus particles.
What type of immune cells recognize and kill virus-infected cells?
Natural Killer (NK) cells.
What is the role of mucus in the first line of defense against viruses?
It traps viruses and helps prevent them from entering the body.
What is the primary role of cilia in the first line of defense against viruses?
To sweep contaminated mucus toward the pharynx, where it is swallowed and digested.
How many lines of defense does the immune system have against foreign invaders?
Three.
What is the role of dendritic cells in the immune system?
Dendritic cells engulf viruses and dead virus-infected cells, migrate to a lymph node where they activate T lymphocytes, and activate CD4 and CD8 cells to form clones of helper T (TH) cells, cytotoxic T (TC) cells, and memory cells.
What is the function of TH cells in the immune system?
TH cells form a clone of helper T cells and memory cells, activate CD8 cells to form a clone of cytotoxic T cells and memory cells, and activate B cells to form a clone of plasma cells and memory B cells.
What is the function of TC cells in the immune system?
TC cells migrate to the site of infection, attack and kill the infected cells, and release perforins to destroy the infected cells.
What is the function of plasma cells in the immune system?
Plasma cells release antibodies, which travel via blood to the site of infection, neutralize viruses by covering the proteins that allow the virus to bind to and enter our cells, and enhance phagocytosis by neutrophils and macrophages through agglutination and complement activation.
What is the difference between cellular and humoral immunity?
Cellular immunity involves the activation of T cells to attack infected cells, while humoral immunity involves the production of antibodies by B cells to neutralize viruses and enhance phagocytosis.
What is a B cell?
A lymphocyte that matures in bone marrow and forms plasma cells and memory cells.
What is a plasma cell?
An effector B cell that produces huge numbers of antibodies.
What is a Helper T cell?
An effector CD4 T cell that stimulates production of cytotoxic T cells and plasma cells, activates macrophages, and acts both directly and indirectly by releasing cytokines.
What is a Cytotoxic T cell?
An effector CD8 T cell that kills invaded body cells and cancer cells.
What is a Regulatory T cell?
An effector CD4 T cell that slows or stops activity of the immune system and is important in controlling autoimmune diseases.
What is a Memory cell?
A descendant of activated B cell or any class of activated T cell that may exist in the body for years, enabling it to respond quickly and efficiently to subsequent encounters with the same antigen.
What is an Antigen-presenting cell (APC)?
Any of several cell types (dendritic cell, macrophage, B cell) that engulfs and digests antigens that it encounters, then presents parts of them on its plasma membrane (bound to an MHC protein) for recognition by T cells bearing receptors for the same antigen.
What is an Antibody?
A protein produced by B cell or by plasma cell that attaches to antigens, causing complement activation, neutralization, precipitation, or agglutination, which marks the antigens for destruction by phagocytes or complement.
What are Perforins and Granzymes?
Perforins create large pores in the target cell’s membrane, allowing entry of apoptosis-inducing granzymes. They are released by TC cells.
What is Complement?
A group of bloodborne proteins activated after binding to antibody-covered antigens or certain molecules on the surface of microorganisms enhances inflammatory response and lyses some microorganisms.
What are Cytokines?
Small proteins that act as chemical messengers between various parts of the immune system.
What are the three things we should do to stay safe during the pandemic?
Stay home, save lives, and wash your hands.
What is COVID-19?
COVID-19 is a highly infectious respiratory illness caused by the SARS-CoV-2 virus.
Where did COVID-19 originate?
COVID-19 was first identified in Wuhan, China.
When did COVID-19 arrive in Wuhan?
COVID-19 arrived in Wuhan in December 2019.
How did COVID-19 spread globally?
COVID-19 spread globally through human-to-human transmission, primarily through respiratory droplets.
What are the symptoms of COVID-19?
The symptoms of COVID-19 include fever, cough, and difficulty breathing.
How can COVID-19 be prevented?
COVID-19 can be prevented by practicing good hygiene, wearing masks, social distancing, and getting vaccinated.
What is the current status of COVID-19?
As of now, COVID-19 is still a global pandemic, but vaccines and other measures have helped to reduce its spread in some areas.
What disease has caused 6.3 million deaths?
The flashcard is incomplete and does not provide enough information to answer this question. Please provide more context.
What causes COVID-19?
COVID-19 is caused by infection with the SARS-CoV-2 virus.
What is SARS?
SARS stands for Severe Acute Respiratory Syndrome.
What causes SARS?
SARS is caused by a virus called SARS-CoV.
What are the symptoms of SARS?
Symptoms of SARS include fever, cough, shortness of breath, and difficulty breathing.
How is SARS transmitted?
SARS is transmitted through respiratory droplets when an infected person talks, coughs, or sneezes.
What is the incubation period of SARS?
The incubation period of SARS is typically 2-7 days.
What is the mortality rate of SARS?
The mortality rate of SARS is estimated to be around 10%.
When did the SARS outbreak occur?
The SARS outbreak occurred in 2002-2003.
Where did the SARS outbreak originate?
The SARS outbreak originated in Guangdong, China.
How was the SARS outbreak contained?
The SARS outbreak was contained through public health measures such as quarantine, isolation, and travel restrictions.
What is coronavirus 2 (SARS-CoV-2)?
It is a virus strain responsible for the COVID-19 pandemic.
What is COVID-19?
It is an infectious disease caused by the SARS-CoV-2 virus.
What are the symptoms of COVID-19?
Fever, cough, shortness of breath, fatigue, body aches, loss of taste or smell, sore throat, congestion, nausea or vomiting, and diarrhea.
How does COVID-19 spread?
It spreads mainly through respiratory droplets when an infected person talks, coughs, or sneezes. It can also spread by touching a surface contaminated with the virus and then touching one’s mouth, nose, or eyes.
What are some preventive measures for COVID-19?
Wearing a mask, washing hands frequently, maintaining social distancing, avoiding large gatherings, and getting vaccinated.
What is the incubation period of COVID-19?
The time between exposure to the virus and the onset of symptoms can range from 2 to 14 days, with an average of 5 days.
What is the mortality rate of COVID-19?
The mortality rate varies depending on age, underlying health conditions, and other factors. The overall mortality rate is estimated to be around 2-3%.
What is the treatment for COVID-19?
There is no specific treatment for COVID-19. Treatment is mainly supportive, and severe cases may require hospitalization and oxygen therapy.
What is the best way to prevent the spread of COVID-19?
The best way to prevent the spread of COVID-19 is to get vaccinated, wear a mask, wash hands frequently, maintain social distancing, and avoid large gatherings.
What is SARS?
SARS stands for Severe Acute Respiratory Syndrome.
What causes SARS?
SARS is caused by a virus called SARS-CoV.
What type of virus is SARS-CoV?
SARS-CoV is a type of coronavirus.
What are the symptoms of SARS?
Symptoms of SARS include fever, cough, and difficulty breathing.
How is SARS transmitted?
SARS is transmitted through respiratory droplets when an infected person talks, coughs, or sneezes.
When did the SARS outbreak occur?
The SARS outbreak occurred in 2002-2003.
Where did the SARS outbreak originate?
The SARS outbreak originated in Guangdong, China.
How many people died from SARS?
According to the World Health Organization, there were 8,096 confirmed cases of SARS and 774 deaths during the 2002-2003 outbreak.
What is CoV-2?
CoV-2 is a strain of coronavirus that causes COVID-19.
What are Variants of Concern (VOCs)?
Variants of Concern (VOCs) are mutated strains of the COVID-19 virus that have been identified as having increased transmissibility, severity, or reduced effectiveness of treatments and vaccines.
What are some examples of Variants of Concern (VOCs)?
Some examples of Variants of Concern (VOCs) include the Alpha variant (B.1.1.7), Beta variant (B.1.351), Gamma variant (P.1), and Delta variant (B.1.617.2).
What is the Alpha variant (B.1.1.7)?
The Alpha variant (B.1.1.7) is a VOC that was first identified in the United Kingdom and has since spread to other countries. It is believed to be more transmissible than the original strain of the virus.
What is the Beta variant (B.1.351)?
The Beta variant (B.1.351) is a VOC that was first identified in South Africa and has since spread to other countries. It is believed to be more transmissible than the original strain of the virus and may be less responsive to some treatments and vaccines.
What is the Gamma variant (P.1)?
The Gamma variant (P.1) is a VOC that was first identified in Brazil and has since spread to other countries. It is believed to be more transmissible than the original strain of the virus and may be less responsive to some treatments and vaccines.
What is the Delta variant (B.1.617.2)?
The Delta variant (B.1.617.2) is a VOC that was first identified in India and has since spread to other countries. It is believed to be more transmissible than the original strain of the virus and may be less responsive to some treatments and vaccines.
What does VOC stand for?
VOC stands for Variant of Concern.
How many VOCs have been declared by WHO?
WHO has declared five VOCs.
What are the names of the five VOCs declared by WHO?
The names of the five VOCs declared by WHO are Alpha, Beta, Gamma, Delta, and Omicron.
What is the full form of WHO?
WHO stands for World Health Organization.
What are the ways in which people can expel air from their respiratory system?
Breathing, coughing, and sneezing.
What are the mucous membranes?
Thin layers of tissue that line various parts of the body, including the eyes, nose, mouth, and throat.
Where are the mucous membranes located?
In various parts of the body, including the eyes, nose, mouth, and throat.
What is the function of the mucous membranes in the eyes and nose?
To protect the eyes and nose from foreign particles and infections.
What is the texture of the mucous membranes?
They are moist and slimy due to the presence of mucus.
What is the role of mucus in the mucous membranes?
To trap and remove foreign particles and microorganisms from the body.
What happens when the mucous membranes are irritated or inflamed?
They may produce excess mucus, leading to symptoms such as a runny nose or watery eyes.
What are some ways to prevent the spread of COVID-19?
Washing hands frequently with soap and water for at least 20 seconds, wearing a mask in public places, practicing social distancing by staying at least 6 feet away from others, avoiding large gatherings, staying home when feeling sick, covering coughs and sneezes with a tissue or elbow, cleaning and disinfecting frequently touched objects and surfaces regularly.
What are some general hygiene measures?
Washing hands frequently with soap and water for at least 20 seconds, covering mouth and nose with a tissue or elbow when coughing or sneezing, avoiding close contact with sick people, avoiding touching face, nose, and mouth with unwashed hands, cleaning and disinfecting frequently touched objects and surfaces regularly, wearing a mask in public places, and staying home when feeling sick.
What is social/physical distancing?
It is a practice of maintaining a safe distance (at least 6 feet) from others to reduce the spread of infectious diseases.
Why is social/physical distancing important?
It helps to reduce the spread of infectious diseases by limiting close contact with others.
What is good respiratory hygiene?
It is a set of practices that help to prevent the spread of respiratory infections. These include covering your mouth and nose with a tissue or your elbow when coughing or sneezing, disposing of used tissues properly, and washing your hands frequently.
Why is good respiratory hygiene important?
It helps to prevent the spread of respiratory infections by reducing the amount of respiratory secretions that are released into the air.
What is the recommended distance for social/physical distancing?
At least 6 feet.
What are some examples of good respiratory hygiene practices?
Covering your mouth and nose with a tissue or your elbow when coughing or sneezing, disposing of used tissues properly, and washing your hands frequently.
How can social/physical distancing and good respiratory hygiene help prevent the spread of COVID-19?
They can help to reduce the spread of COVID-19 by limiting close contact with others and reducing the amount of respiratory secretions that are released into the air.
What is the enzyme angiotensin-converting enzyme 2?
It is an enzyme that is found on the surface of cells in the lungs, arteries, heart, kidney, and intestines.
What is the function of angiotensin-converting enzyme 2?
It converts angiotensin II to angiotensin 1-7, which has vasodilatory and anti-inflammatory effects.
What is the role of angiotensin-converting enzyme 2 in COVID-19?
It is the receptor that allows the SARS-CoV-2 virus to enter human cells.
What happens when the SARS-CoV-2 virus binds to angiotensin-converting enzyme 2?
It enters the human cells and starts replicating, leading to COVID-19 infection.
What is the significance of angiotensin-converting enzyme 2 in hypertension?
It is involved in the regulation of blood pressure and is a target for some antihypertensive drugs.
What is the effect of angiotensin-converting enzyme inhibitors on angiotensin-converting enzyme 2?
They increase the expression of angiotensin-converting enzyme 2, which may have potential therapeutic benefits in COVID-19.
What is the effect of angiotensin receptor blockers on angiotensin-converting enzyme 2?
They do not affect the expression of angiotensin-converting enzyme 2.
What is ACE2?
ACE2 stands for Angiotensin-Converting Enzyme 2, which is a protein found on the surface of many types of cells in the human body.
Where is ACE2 abundantly present in the human body?
ACE2 is abundantly present in the lungs, heart, kidneys, and intestines.
What is the function of ACE2 in the human body?
ACE2 plays a crucial role in regulating blood pressure, fluid balance, and electrolyte homeostasis.
What is the significance of ACE2 in COVID-19?
ACE2 is the receptor that allows the SARS-CoV-2 virus to enter human cells, which is the cause of COVID-19.
What happens when the SARS-CoV-2 virus binds to ACE2?
When the virus binds to ACE2, it enters the cell and begins to replicate, leading to COVID-19 infection.
What are the other diseases associated with ACE2?
ACE2 has been implicated in the pathogenesis of other diseases, such as hypertension, diabetes, and cardiovascular disease.
What is the pericardium?
The pericardium is a double-layered sac that surrounds the heart and protects it from infection or inflammation from nearby organs.
What are the two layers of the pericardium?
The two layers of the pericardium are the fibrous pericardium and the serous pericardium.
What is the fibrous pericardium?
The fibrous pericardium is the tough, outer layer of the pericardium that is made of dense connective tissue.
What is the serous pericardium?
The serous pericardium is the inner layer of the pericardium that is made of two layers: the parietal layer and the visceral layer.
What is the parietal layer of the serous pericardium?
The parietal layer of the serous pericardium lines the fibrous pericardium and secretes a small amount of serous fluid to lubricate the heart.
What is the visceral layer of the serous pericardium?
The visceral layer of the serous pericardium is also known as the epicardium, which is the outermost layer of the heart wall that covers the myocardium.
What is the myocardium?
The myocardium is the middle layer of the heart wall that is composed of cardiac muscle tissue and is responsible for the contraction of the heart.
What is the function of the pericardium?
The pericardium protects the heart from infection or inflammation from nearby organs and provides a lubricated environment for the heart to beat in.
What is the function of the myocardium?
The myocardium is responsible for the contraction of the heart, which pumps blood throughout the body.
What is the function of the spike proteins in a virus?
To help the virus attach to and enter host cells.
What is the role of spike proteins in viral infection?
To facilitate viral entry into host cells.
What is the importance of spike proteins for a virus?
They are crucial for the virus to infect host cells.
What is the mechanism of action of spike proteins in a virus?
They bind to specific receptors on the surface of host cells, allowing the virus to enter the cell.
What is the structure of spike proteins in a virus?
They are protruding structures on the surface of the virus, made up of protein subunits.
What is the significance of spike proteins in the COVID-19 virus?
They are the target of many vaccines and treatments being developed to combat the virus.
What are some common symptoms of COVID-19?
Loss of taste and smell, sore throat, and muscle aches.
What is anosmia?
Anosmia is the loss of the sense of smell.
What is ageusia?
Ageusia is the loss of the sense of taste.
What is dysgeusia?
Dysgeusia is a distortion of the sense of taste.
What is a common symptom of a sore throat?
Pain or discomfort in the throat.
What causes muscle aches?
Muscle aches can be caused by inflammation or injury to the muscles.
Are loss of taste and smell always symptoms of COVID-19?
No, loss of taste and smell can also be caused by other factors such as allergies or a common cold.
What are interleukin 1 (IL1), IL-2, IL-6, and interferon?
They are cytokines, which are proteins that play a role in cell signaling.
What is the function of interleukin 1 (IL1)?
It is involved in the regulation of immune and inflammatory responses.
What is the function of IL-2?
It stimulates the growth and proliferation of T cells, which are important for immune responses.
What is the function of IL-6?
It is involved in the regulation of immune responses and inflammation.
What is the function of interferon?
It is involved in the regulation of immune responses and has antiviral activity.
What are the sources of IL1, IL-2, IL-6, and interferon?
They are produced by various cells of the immune system, including T cells, B cells, and macrophages.
What happens when there is an imbalance in the levels of IL1, IL-2, IL-6, and interferon?
It can lead to various immune-related disorders and diseases.
What are some examples of diseases associated with IL1, IL-2, IL-6, and interferon?
Examples include rheumatoid arthritis, multiple sclerosis, and hepatitis C.
What is a cytokine storm?
An overreaction of the immune system that can cause inflammation and damage to organs.
What causes a cytokine storm?
An excessive release of cytokines, which are signaling molecules that help regulate the immune response.
What are some conditions that can lead to a cytokine storm?
Infections, autoimmune diseases, and some types of cancer treatments.
What are some symptoms of a cytokine storm?
Fever, fatigue, inflammation, and organ damage.
What is the role of cytokines in the immune system?
Cytokines help regulate the immune response by signaling between cells.
What are some treatments for a cytokine storm?
Anti-inflammatory drugs, immunosuppressants, and cytokine inhibitors.
Why is a cytokine storm dangerous?
It can cause severe inflammation and damage to organs, which can be life-threatening.
What is an example of a disease that can cause a cytokine storm?
COVID-19 is an example of a disease that can cause a cytokine storm in some patients.
What is the antiviral immune response?
It is the body’s natural defense mechanism against viral infections.
What are the two types of antiviral immune responses?
Innate and adaptive.
What is the innate antiviral immune response?
It is the first line of defense that provides immediate, non-specific protection against viruses.
What are the components of the innate antiviral immune response?
Physical barriers, such as skin and mucous membranes, and immune cells, such as natural killer cells and macrophages.
What is the adaptive antiviral immune response?
It is a specific response that develops over time after exposure to a virus.
What are the components of the adaptive antiviral immune response?
B cells, which produce antibodies, and T cells, which directly attack infected cells.
What is the role of interferons in the antiviral immune response?
They are signaling proteins that help to activate the innate and adaptive immune responses.
What is the role of cytokines in the antiviral immune response?
They are signaling molecules that help to coordinate the immune response and recruit immune cells to the site of infection.
What is the immune system response to SARS?
The immune system produces cytokines to fight the virus.
What happens when there is excessive production of cytokines after SARS infection?
Excessive production of cytokines can lead to a cytokine storm, causing inflammation and damage to organs.
What is a cytokine storm?
A cytokine storm is an overreaction of the immune system, causing excessive inflammation and damage to organs.
What are the symptoms of a cytokine storm?
Symptoms of a cytokine storm include fever, fatigue, and organ dysfunction.
How is a cytokine storm treated?
Treatment for a cytokine storm may include anti-inflammatory medications and immunosuppressants.
Can a cytokine storm be fatal?
Yes, a cytokine storm can be fatal if not treated promptly and effectively.
What other diseases can cause a cytokine storm?
Other diseases that can cause a cytokine storm include influenza, Ebola, and COVID-19.
What is the role of cytokines in the immune system?
Cytokines are signaling molecules that regulate the immune response and help fight infections.
What is the potential consequence of CoV-2 infection?
Acute respiratory illness.
What is CoV-2?
A virus that causes COVID-19 disease.
What does COVID-19 stand for?
Coronavirus Disease 2019.
What are the common symptoms of COVID-19?
Fever, cough, and difficulty breathing.
How is COVID-19 transmitted?
Through respiratory droplets when an infected person talks, coughs, or sneezes.
What are some preventive measures for COVID-19?
Wearing a mask, washing hands frequently, and practicing social distancing.
What is the incubation period for COVID-19?
2-14 days.
What is the mortality rate of COVID-19?
Varies by age and underlying health conditions, but estimated to be around 1-2%.
What is the best way to prevent the spread of COVID-19?
Getting vaccinated and following public health guidelines.
What is hypertension?
Hypertension, also known as high blood pressure, is a condition in which the force of blood against the artery walls is too high.
What are the risk factors for hypertension?
Risk factors for hypertension include family history, age, obesity, smoking, lack of physical activity, stress, and certain chronic conditions.
What is obesity?
Obesity is a medical condition characterized by excessive body fat that increases the risk of health problems.
What are the health risks associated with obesity?
Health risks associated with obesity include type 2 diabetes, heart disease, stroke, high blood pressure, and certain cancers.
What is diabetes mellitus?
Diabetes mellitus, commonly referred to as diabetes, is a chronic condition in which the body is unable to properly regulate blood sugar levels.
What are the two main types of diabetes mellitus?
The two main types of diabetes mellitus are type 1 diabetes, which is an autoimmune disease, and type 2 diabetes, which is often associated with lifestyle factors such as obesity and lack of physical activity.
What are the health risks associated with diabetes mellitus?
Health risks associated with diabetes mellitus include heart disease, stroke, kidney disease, nerve damage, and blindness.
What are cardiovascular diseases?
Diseases that affect the heart and blood vessels, such as coronary artery disease, heart failure, and stroke.
What are respiratory diseases?
Diseases that affect the lungs and breathing, such as asthma, chronic obstructive pulmonary disease (COPD), and pneumonia.
What are renal diseases?
Diseases that affect the kidneys, such as chronic kidney disease, kidney stones, and glomerulonephritis.
What is the name of the guideline?
Living Guideline
What is the version number of the guideline?
Tenth version
When was the tenth version of the guideline released?
April
What is the purpose of the Living Guideline?
To provide up-to-date guidance on a particular topic.
Who is responsible for creating and updating the Living Guideline?
A group of experts in the relevant field.
What is the difference between a living guideline and a traditional guideline?
A living guideline is updated regularly to reflect new evidence and changes in practice, while a traditional guideline is typically only updated every few years.
What are the benefits of a living guideline?
It ensures that healthcare providers have access to the most current and accurate information, which can improve patient outcomes.
What is the potential downside of a living guideline?
It can be challenging to keep up with the frequent updates and changes.
