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Lymphatic immune system

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Lymphatic immune system

  1. 1. Lymphatic Immune system Biology case (3) G5 PBL
  2. 2. Objectives: ● Define the lymphatic system, explain it function and identify it components. (General). ● Describe the structure of the lymphatic system. ● Describe each component of the lymphatic system ( definition, physiology, histology). ● Describe the mechanism of circulation. ● Describe how the lymphatic system works with others systems. ● Compare between lymphatic and cardiovascular system. ● Diseases of lymphatic system (edema). ● Define the Immune system, explain it function and identify it components. ● Explain the types of Immune system. ● Describe the difference between lymphatic and Immune system.
  3. 3. lymphatic system Do you know what the lymphatic system is ? it is network of tissues and organs that help rid the body of toxins, waste and other unwanted materials. What does the lymphatic system consist of ? lymphatic vessels, lymph nodes, the spleen, and other lymphatic organs.
  4. 4. The Main functions of the lymphatic system : The lymphatic system has four main functions that contribute to homeostasis: (1) Lymphatic capillaries absorb excess tissue fluid and return it to the bloodstream (2) in the small intestines, lymphatic capillaries called lacteals absorb fats in the form of lipoproteins and transport them to the bloodstream (3) the lymphatic system is responsible for the production, mainte- nance, and distribution of lymphocytes (4) the lymphatic system helps defend the body against pathogens
  5. 5. STRUCTURE OF LYMPHATIC SYSTEM The lymphatic system consists of lymphatic vessels and lymphatic organs THE LYMPHATIC VESSELS LYMPH excessive tissue fluid carried by lymphatic vessels Collects lymph from lymph capillaries Delivers lymph to lymph nodes Returns fluid to circulatory veins near the heart
  6. 6. Fluid & plasma proteins are not all resorbed at the capillary beds and must be returned to the blood to maintain blood volume …lymphatic vessels accomplish this One-way system, lymph flows toward the heart Lymph vessels include: Microscopic, permeable, blind-ended capillaries Lymphatic collecting vessels Trunks and ducts
  7. 7. The lymphatic organs 1. Primary lymphoid organs: Where lymphocytes are generated a. Bone marrow B lymphocytes are mature in bone marrow Produce plasma cells, which secrete antibodies Antibodies immobilize antigens and “tag” them for destruction by leukocytes (WBCs)
  8. 8. b. Thymus gland T lymphocytes are mature in thymus Manage the immune response Attack and destroy foreign cells 2. Secondary lymphoid organs : initiate adaptive immune responses Lymph node Spleen Appendix Peyer’s patches Tonsils
  9. 9. Lymphoid organ: Lymph nodes. It is a small, bean-shaped organ that serves as a filtering and processing center for your immune system. *Approximately 600 lymph nodes are scattered throughout the human body. They can exist singly or in closely connected groups called chains. *Lymph nodes are connected to their neighbors by a sort of network of tubes called lymphatic vessels. *lymph: it’s a clear fluid contains more white blood cells than plasma.
  10. 10. Lymph nodes
  11. 11. *Lymphocytes: *Macrophages: 1- They detect if there is any viruses or bacteria 1 - They will directly phagocytes the viruses in the lymphatic fluid. and bacteria. 2 - They produce antibodies to combat viruses and bacteria.
  12. 12. Types of lymphocytes: 1 - T cells: a type of white blood cell and they help protect the body from infection and may help fight cancer. Location : in cortex. 2 - B cells: A type of white blood cell that makes antibodies. Location: in germinal center.
  13. 13. Function of lymph nodes 1. Filtration. 1. Immune system activation. 1. Production of lymphocytes.
  14. 14. Other Lymphoid Organs: spleen Spleen : is the largest lymphatic organ. Located: in the upper left abdominal quadrant. Contains two tissue types: *White pulp *Red pulp
  15. 15. Function of the spleen 1 - acts as a blood filter and controls the amount of red blood cells and blood storage in the body. 2 - help to fight infection.
  16. 16. Other Lymphoid Organs : Tonsils Definition : The tonsils are small masses of lymphoid tissue that ring the pharynx (the throat) . The function: Their job is to trap and remove any bacteria or other foreign pathogens entering the throat. Disorder : sometimes they become congested with bacteria and become red, swollen, and sore,a condition called tonsillitis .
  17. 17. Lymphatic Vessels Lymphatic vessels are tupe-shaped structures of the lymphatic system that transport fluid away from tissues - the lymph. This fluid becomes the interstitial fluid that surrounds cells. Functions: Lymphatic vessels collect and filter this fluid before directing it toward blood vessels near the heart. Then, that lymph re-enters blood circulation. Returning lymph to the blood helps to maintain normal blood volume and pressure. It prevents edema, the excess accumulation of fluid around tissues.
  18. 18. Lymphatic Vessels Structure: Large lymphatic vessels are composed of three layers. - tunica intima, tunica media, and tunica adventitia. Tunica Intima - lymph vessel inner layer composed of smooth endothelium (type of epithelial tissue). This layer contains valves in some lymph vessels to prevent fluid backflow. Tunica Media - lymph vessel middle layer composed of smooth muscle and elastic fibers. Tunica Adventitia - lymph vessel strong outer covering composed of connective tissue as well as collagen and elastic fibers. The adventitia attaches lymphatic
  19. 19. THYMUS - The thymus gland is the main organ of the lymphatic system. Located in the upper chest region. - The primary function of this gland is to promote the development of specific cells of the immune system called T lymphocytes. - T lymphocytes (T-cells) are white blood cells that protect against foreign organisms (bacteria and viruses) that have managed to infect body cells. They also protect the body from itself by controlling cancerous cells. - From infancy to adolescence, the thymus is relatively large in size. After puberty, the thymus begins to decrease in size and continues to shrink with age.
  20. 20. THYMUS ANATOMY The thymus is a two-lobed structure that is positioned in the upper chest cavity. The thymus is situated above the pericardium of the heart, in front of the aorta, between the lungs, below the thyroid, and behind the breastbone. The thymus has a thin outer covering called a capsule.
  21. 21. THYMUS HISTOLOGY Thymus consist of three cells: Epithelial cells - tightly packed cells that give shape and structure to the thymus. Lymphocytes - immune cells that protect against infection and stimulate an immune response. Kulchitsky cells { neuroendocrine }- hormone-releasing cells. Each lobe of the thymus contains many smaller divisions called lobules. A lobule consists of an inner area called the medulla and an outer region called the cortex. The cortex region contains immature T lymphocytes. The medulla region contains the larger, mature T-lymphocytes. While T lymphocytes mature in the thymus, they originate from bone marrow stem cells. Immature T-cells migrate from the bone marrow to the thymus via the blood. The "T " in T lymphocyte stands for thymus- derived.
  22. 22. Vermiform Appendix Anatomy In Latin, the term "vermiform" means worm-shaped. Although the appendix ranges from a length of two centimeters to twenty centimeters, the average length is ten centimeters. The appendix usually has a diameter between seven and eight millimeters. The vermiform appendix is attached dorsomedially to the end of the cecum where all three taeniae converge. It is 2 to 15 cm long and lies often intraperitoneally retrocecal or in the lesser pelvis. The appendix is attached to the posterior abdominal wall by the mesoappendix. Here taeniae, haustra, semilunar folds and appendices epiploicae are all absent.
  23. 23. Vermiform Appendix Histology Histologically the appendix looks quite similar to the colon and cecum. A distinctive feature is however the numerous lymph follicles and the parafollicular tissue in the connective tissue layer of the mucosa (lamina propria mucosae) and the submucosa. The crypts are particularly deep so that the follicles are in close contact to the intestinal lumen. M-cells (microfold cells) are found in the epithelium which access antigens from the intestinal lumen. As the appendix lacks taeniae it has a regular outer longitudinal musculature.
  24. 24. Circulatory System Similarities Lymphatic System ● Both are circulatory systems. ● The medium is contained in vessels. Comparison of the Circulatory and Lymphatic Systems
  25. 25. Circulatory System Differences Lymphatic System ● Closed continuous circuit throughout the body. ● Comprises of the heart, arteries, veins and capillaries. Structure ● Open circuit from the tissues into lymphatic vessels. ● Comprises of right lymphatic duct and thoracic duct, lymph nodes, lymphatic vessels and capillaries, thymus and spleen. Blood Medium Lymph Erythrocytes, leucocytes, platelets, dissolved substances, waste products and protein plasma. Composition of medium Leucocytes, dissolved substances, waste products and protein plasma.
  26. 26. Circulatory System Differences Lymphatic System Collects and distributes oxygen, nutrients, waste products and hormones to the tissues of the entire body. Role of medium Collects and removes waste products left behind in the tissues. By the kidneys. Filtration By lymph nodes. Blood is visible and damaged blood vessels cause obvious signs. Vessel damage Lymph is invisible and damaged lymphatic system is difficult to detect. Blood is propelled throughout the body by the pumping of the heart and the muscular movement. Propulsion Lymph is not pumped. It passively flows from the tissues into the lymph capillaries aided by muscular movement, breathing mechanism and blood circulation.
  27. 27. circulation lymphatic system •Mingled among the blood capillaries throughout your body is another network of tiny, thin-walled vessels called lymphatic capillaries. Lymphatic capillaries are designed to pick up the fluid that leaks into your tissues from your bloodstream and return it to your circulatory system.
  28. 28. circulation lymphatic system •Just like their neighboring blood capillaries, your lymphatic capillaries join into progressively larger tubes called lymphatic vessels, which transport the fluid from your tissues (this fluid is now called lymph) toward the center of your body. Eventually, the lymph is returned to your bloodstream through two large ducts in the upper central portion of your chest. •The largest of these lymphatic ducts, the thoracic duct, originates in your abdomen, where it collects lymph from your legs, intestine, and other internal organs. As it proceeds upward into your chest, the thoracic duct collects lymph from your thoracic organs, your left arm, and the left side of your head and neck.
  29. 29. Circulation Of the Lymphatic System The right lymphatic duct, which is much shorter than the thoracic duct, begins high in the right side of your chest. It collects lymph from the right side of your chest wall, your right arm, and the right side of your head and neck. The thoracic duct and the right lymphatic duct reintroduce lymph to your bloodstream through the large veins returning to your heart from your arms: the left and right subclavian veins.
  30. 30. How the lymphatic system works with other systems?Cardiovascular system Lymphatic vessels pick up leaked plasma and proteins; spleen destroys aged RBCs, stores iron, and removes debris from blood; immune cells protect cardiovascular organs from specific pathogens Blood is the source of lymph; lymphatics develop from veins; blood provides the route for circulation of immune elements Nervous system The lymphatic vessels pick up leaked plasma fluid and proteins in the peripheral nervous system structures; immune cells protect peripheral nervous system structures from specific pathogens The nervous system innervates larger lymphatic vessels;the brain helps regulate immune response
  31. 31. How the lymphatic system works with other systems?Urinary system Lymphatic vessels pick up leaked fluid and proteins from urinary organs; immune cells protect urinary organs from specific pathogens Urinary system eliminates wastes and maintains homeostatic water/ acid-base/electrolyte balance of the blood for immune cell functioning; urine flushes some pathogens out of the body Endocrine System Lymphatic vessels pick up leaked fluids and proteins; lymph distributes hormones; immune cells protect endocrine organs from pathogens The thymus produces hormones that promote development of lymphoid organs and
  32. 32. How the lymphatic system works with other systems?Reproductive system Lymphatic vessels pick up leaked fluid and proteins from reproductive organs; immune cells protect the organs from specific pathogens Acidity of vaginal secretions prevents bacterial multiplication Respiratory system Lymphatic vessels pick up leaked fluid and proteins from respiratory organs; immune cells protect respiratory organs from specific pathogens; plasma cells in the respiratory mucosa ecrete IgA to prevent pathogen invasion of deeper tissues The lungs provide oxygen needed by lymphoid/immune cells and eliminate carbon dioxide; the pharynx houses tonsils; the respiratory “pump” aids lymph flow
  33. 33. How the lymphatic system works with other systems?Integumentary System Lymphatic vessels pick up leaked plasma fluid and proteins from the dermis; lymphocytes in lymph enhance the skin’s protective role by defending against specific pathogens The skin’s keratinized epithelium provides a mechanical barrier to pathogens; acid pH of skin secretions inhibits growth of bacteria on skin Digestive system Lymphatic vessels pick up leaked fluids and proteins from digestive organs; lymph transports some products of fat digestion to the blood; lymphoid nodules in the wall of the intestine prevent invasion of pathogens The digestive system digests and absorbs nutrients needed by cells of lymphoid organs; gastric acidity inhibits pathogens’ entry into blood
  34. 34. How the lymphatic system works with other systems?Skeletal system Lymphatic vessels pick up leaked plasma fluid and proteins from the periostea; immune cells protect bones from specific pathogens The bones house hematopoietic tissue (red marrow) which produces the cells that populate the lymphoid organs and provide body immunity Muscular system Lymphatic vessels pick up leaked fluid and proteins from skeletal muscle; immune cells protect muscles from specific pathogens The skeletal muscle “pump” aids the flow of lymph; muscles protect superficial lymph nodes
  35. 35. Difference between Immune System and Lymphatic SystemLymphatic System Immune System The main function The main function is fluid recovery, immunity, and lipid absorption Provide long term immunity and defend against foreign substances by activating immune responses The anatomy Has specific anatomy No specific anatomy Made of composed of lymph nodes, lymph vessels, and other related organs while made up of basically B and T lymphocytes
  36. 36. Difference between Immune System and Lymphatic System Lymphatic System Immune System Associated with associated with the cardiovascular system mainly associated with nervous and endocrine systems The relationship The products of the immune system are transported in the lymphatic system
  37. 37. Disease of the lymphatic system Lymphedema Lymphedema is a build-up of lymph fluid in the fatty tissues just under your skin. This build-up causes swelling (or edema), most often in the arms or legs. Lymphedema can result from surgery or radiation therapy to treat certain cancers.
  38. 38. Types of lymphedema Primary Lymphedema It’s largely hereditary, meaning you’re born with it. This is less common than secondary lymphedema. You’re more likely to have primary lymphedema if a family member is also affected.. Secondary lymphedema Secondary lymphedema results from an identifiable damage to or obstruction of normally-functioning lymph vessels and nodes.
  39. 39. Causes of lymphedema Surgery Radiation treatment for cancer Cancer Infection
  40. 40. Symptoms of lymphedema Fever Decreased flexibility of hands Aching and pain Skin rash Swelling of the arm Weight loss
  41. 41. Prevention of lymphedema Avoid insect bites and sunburns Do not carry a heavy purse on an affected arm Practice skin hygiene Keep the body adequately hydrated
  42. 42. DEFINITION OF IMMUNE SYSTEM The bodily system that protects the body from foreign substances, cells, and tissues by producing the immune response and that includes especially the thymus, spleen, lymph nodes, special deposits of lymphoid tissue (as in the gastrointestinal tract and bone marrow), macrophages, lymphocytes including the B cells and T cells, and antibodies.
  43. 43. FUNCTION OF THE IMMUNE SYSTEM The major function of the immune system is to protect the host from environmental agents such as microbes or chemicals, thereby preserving the integrity of the body. This is done by the recognition of self and response to nonself. The immune response has been artificially divided into innate immunity (resistance) and specific immunity. Specific immunity is further divided into humoral immunity, the one involved with antibody, and cellular immunity, which is orchestrated by T cells.
  44. 44. COMPONENTS OF THE IMMUNE SYSTEM● Lymph nodes: Small, bean-shaped structures that produce and store cells that fight infection and disease and are part of the lymphatic system. ● Spleen: The largest lymphatic organ in the body, which is on your left side, under your ribs and above your stomach, contains white blood cells that fight infection or disease. ● Bone marrow: The yellow tissue in the center of the bones produces white blood cells. ● Lymphocytes: These small white blood cells play a large role in defending the body against disease.The two types of lymphocytes are B-cells, which make antibodies that attack bacteria and toxins, and T-cells, which help destroy infected or cancerous cells. Killer T-cells are a subgroup of T-cells that kill cells that are infected with viruses and other pathogens or are otherwise damaged. Helper T-cells help determine which immune responses the body makes to a particular pathogen.
  45. 45. ● Thymus: This small organ is where T-cells mature. This often- overlooked part of the immune system, which is situated beneath the breastbone (and is shaped like a thyme leaf, hence the name), can trigger or maintain the production of antibodies that can result in muscle weakness. ● Leukocytes: These disease- fighting white blood cells identify and eliminate pathogens and are the second arm of the innate immune system. A high white blood cell count is referred to as leukocytosis.
  46. 46. Immune system The Immune system is composed of two major subdivisions. They are : Non specific immunity. Specific immunity.
  47. 47. Non specific immunity Nonspecific immunity includes the external physical and chemical barriers provided by the skin and mucous membranes. It also includes various internal defenses, such as antimicrobial substances, natural killer cells, phagocytes, inflammation, and fever. The nonspecific line of defences are : First line of defence Second line of defence
  48. 48. First line of defence (skin and mucous) The skin provides a barriers that discourage pathogens and foreign substances from penetrating the body and causing disease. With its many layers of closely packed, keratinized cells,the epidermis—provides a formidable physical barrier to the entrance of microbes The epithelial layer of mucous membranes,secretes a fluid called mucus that lubricates and moistens the cavity surface. It traps many microbes and foreign substances.
  49. 49. Second Line of Defense (Internal Defenses) When pathogens penetrate the physical and chemical barriers of the skin and mucous membranes, they encounter a second line of defense: internal antimicrobial substances, phagocytes, natural killer cells, inflammation, and fever.
  50. 50. Antimicrobial An antimicrobial is an agent that kills or inhibits the growth of microorganisms. These agents interfere with the growth and reproduction of causative organisms like bacteria, fungi, parasites, virus etc. Phagocytes Phagocytes are specialized cells that ingest microbes or other particles.The two major types of phagocytes are neutrophils and macrophages Natural killer cells They have the ability to kill a wide variety of infected body cells and certain tumor cells. They attack any body cells that display abnormal or unusual plasma membrane proteins.
  51. 51. Fever Fever is an abnormally high body temperature that occurs because the hypothalamic thermostat is reset. Elevated body temperature intensifies the effects of interferons, inhibits the growth of some microbes, and speeds up body reactions that aid repair. Inflammation Inflammation is a nonspecific, defensive response of the body to tissue damage. It is caused due to pathogens, abrasions, chemical irritations, distortion or disturbances of cells, and extreme temperatures. Inflammation is an attempt to dispose of microbes, toxins, or foreign material and tissue repair.
  52. 52. Third line of Defences Also known as Acquired Immune system It is specific Long time period between exposure and maximal response Has immunological memory Is flexible Components are T lymphocytes and B lymphocytes
  53. 53. Activation of lymphocytes Lymphocytes are formed in the bone marrow Those that are matured in the thymus gland are called T-cells Those that mature in the bone marrow are called B-cells Before B-cells leave bone marrow (antibodies) and T-cells leave thymus, they must become immunocompetent. This is achieved by developing surface receptors capable of recognizing various antigens. Specific immunity is two kinds: ● Cell-mediated immunity ● Antibody-mediated immunity
  54. 54. Cell-mediated Immunity Involves T-cells: They are four kinds: ● Cytotoxic T-cells ● Helper T-cells ● Memory T-cells ● Suppressor T-cells Once a T-cell (helper or cytotoxic T-cell) binds to an antigen, it is activated. It undergoes clonal selection (making clones) It starts secreting many cytokines, one of which activates cytotoxic T-cells, B-cells
  55. 55. Cytotoxic T-cells are the soldiers. They recognise and attach to target cells which are: Infected body cells Tumour cells Cells of a tissue transplant Cytotoxic T cells have two principal mechanisms for killing infected target cells: By producing protein digesting enzymes that causes apoptosis of infected cells. Microbes are released and killed by phagocytes By producing perforin that insert into the plasma membrane of the target cell and creates
  56. 56. Antibody-mediated Immunity B-cells, unlike T-cells, are rarely found in circulation. Upon interaction with foreign antigen and usually with the assistance of T helper cells, B lymphocytes become mature antibody secreting cells called plasma cells. A few days after exposure to antigens, plasma cells secrete hundreds of millions of antibodies each day for 4-5 days, after that they die. Antibodies produced by a clone of plasma cells enter the circulation and form antigen–antibody complexes with the antigen. Memory B cells do not secrete antibodies. Instead, they can quickly differentiate into more plasma cells and more memory B cells should the same antigen reappear at a future time.
  57. 57. Structure of Antibodies An antibody (also called immunoglobulins) can combine specifically with the epitope on the antigen, the antibody’s structure matches its antigen Almost all antibodies are made of 4 polypeptide chain. 2 of them are identical, called heavy chains 2 of them are light chains.
  58. 58. Function of Antibodies Antibodies inactivate antigens in a number of ways: Complement fixation Neuralization Agglutination or precipitation The most Important is the complement system. It is activated when antibodies bind to antigens and are recognized by complement protein. One result of complement fixation is formation of substances that that make holes in the foreign cell’s surface. Agglutinating and precipitating antigen: Because antibodies have two or more sites for binding to antigen, the antigen– antibody reaction may cross-link pathogens
  59. 59. References :- (Books) ● Human Biology Book. Sylvia S. Mader & Michael Windelspecht. 12th edition. chapter 7.pages 137 and 140 ● Essential of human anatomy and physiology 11th edition pg. no. 399 402 , 403 ● Human biology 14th edition MC GRAW-HILL EDUCATION, chp 7, pg no.132 ● Essential of human anatomy and physiology 11th edition pg. no. 430 ● Principles of Anatomy and Physiology 13th ed - G. Tortora, B. Derrickson
  60. 60. References:- (Websites) ● http://www.livestrong.com/article/73427-human-body-systems-work-immune ● http://www.livescience.com/26983-lymphatic-system.html ● https://www.google.com.sa/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&cad=rja&uact=8&ve d=0ahUKEwiynLO9zprTAhUICBoKHaVbDXcQFghKMAY&url=http%3A%2F%2Fstudy.com%2F academy%2Flesson%2Flymphatic-vessels-definition-function- quiz.html&usg=AFQjCNFjHS_1yefHS0JyddYSbKbq_lKnFQ&sig2=8E-uVv2FEaQ7JRKLU2Eq4g ● http://www.kean.edu/~jfasick/docs/Fall%2009%20&%20SP10%20%20A&PII/Chapter%2020.pdf
  61. 61. Thank you

Editor's Notes

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    T lymphocytes-These cells have not yet developed the ability to distinguish cells of the body from foreign cells.
    Mature T-lymphocytes-These cells have the ability to identify self and have differentiated into specialized T lymphocytes.
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    •Your circulatory system consists of a pump (your heart) and a network of tubes that conduct blood throughout your body (your blood vessels). With each heartbeat, blood is forced into your arteries, which carry blood away from your heart and toward all of your tissues and organs. As your arteries travel farther from your heart, they divide into progressively smaller vessels called arterioles, which themselves divide into tiny, thin-walled, somewhat leaky vessels called capillaries.
    •As blood travels through your capillaries, oxygen, nutrients, and fluid are pushed into the surrounding tissues, and carbon dioxide and cellular wastes are retrieved. The blood then proceeds on its way, coursing into progressively larger vessels called venules and then into even larger veins, which finally return the blood to your heart. If the fluid that leaked into your tissues from your bloodstream remained there, your cells would soon drown in the excess. That's where your lymphatic system picks up the ball.

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    SKIN
    In addition, periodic shedding of epidermal cells helps remove microbes at the skin surface. Bacteria rarely penetrate the intact surface of healthy epidermis.
    If this surface is broken by cuts, burns, or punctures, however, pathogens can penetrate the epidermis and invade adjacent tissues or circulate in the blood to other parts of the body.
    Mucous

    The mucous membrane of the nose has mucus-coated hairs that trap and filter microbes, dust, and pollutants from inhaled air.
    The mucous membrane of the upper respiratory tract contains cilia on the surface of the epithelial cells it propels inhaled dust and microbes.
    Coughing and sneezing accelerate movement of mucus and its entrapped pathogens out of the body.


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    PHAGOCYTES

    When an infection occurs, neutrophils and monocytes migrate to the infected area.
    During this migration, the monocytes enlarge and develop into actively phagocytic macrophages called wandering macrophages.
    NATURAL KILLER CELLS
    They bind to target cells, which causes the release of granules containing toxic substances.
    As a result, extracellular fluid flows into the target cell and the cell bursts.

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    INFLAMMATION
    In each case, the inflammatory response has three basic stages: (1) vasodilation and increased permeability of blood vessels, (2) emigration (movement) of phagocytes from the blood into interstitial fluid, and, ultimately, (3) tissue repair.
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