Chapter 5. Lymphatic System

  1. lymphatic system consists of what components?
    • lymphatic vessels
    • lymphatic organs
    • lymphocytes
  2. lymphatic vessels contain what?
    contain a fluid called lymph
  3. lymphatic organs include what?
    • lymph nodes
    • tonsils
    • spleen
    • thymus gland
  4. lymphocytes, which include
    B cells and T cells
  5. what are the 2 major functions the lymphatic system has?
    • It drains the tissues of excess interstitial fluid
    • It participates in immunity
  6. Recall that some H2O moves from the blood into the interstitium as cells undergo
    gas, nutrient, and waste exchange with the capillaries
  7. can the H2O in the interstitial fluid diffuse into body cells if needed
  8. If there is too much H2O in the interstitium, where does the interstitial fluid drain to?
    the excess interstitial fluid drains into a nearby lymphatic vessel (usually a lymphatic capillary)
  9. what would happen if the interstitial fluid were to stay in the interstitium? 
    what is it called?
    the tissues would swell (edema), which causes tissue damage.
  10. what is the new name that is given to the interstitial fluid once it enters the lymphatic capillary?
    Once inside of a lymphatic capillary, the interstitial fluid is called lymph
  11. what is lymph?
    lymph is any excess interstitial fluid found within the lymphatic vessels of the body
  12. what eventually happens to the excess interstitial fluid that enters the lymphatic capillary/vessels?
    The excess interstitial fluid will eventually make it back to the blood because lymphatic vessels ultimately merge with veins.
  13. What happens to any pathogens (viruses, bacteria, etc.) that happen to be in the interstitium trying to invade body cells?
    will also be swept into the lymphatic capillaries as a component of lymph (just like a swimmer may be swept away from the shore by a tidal wave).
  14. how does immunity help in the lymphatic system?
    resistance to disease
  15. how does immunity function in the lymphatic system ?
    achieved by the leukocytes (white blood cells) of the body
  16. Because of its role in immunity...
    the lymphatic system is also called the immune system.
  17. The lymphatic system begins with the..
    lymphatic capillaries, which are the smallest lymphatic vessels
  18. like a blood capillary, a lymphatic capillary consists of
    endothelial cells
  19. there are 2 major ways that a lymphatic capillary differs from a blood capillary, what are they?
    • A lymphatic capillary lacks a basement membrane
    • The endothelial cells of a lymphatic capillary overlap
  20. endothelial cells of a lymphatic capillary overlap, this arrangement allows for what
    unidirectional flow of fluid into the lymphatic capillary
  21. As excess interstitial fluid approaches a lymphatic capillary what happens to the endothelial cells?
    endothelial cells spread apart, forming large spaces between each other
  22. the large spaces formed between the endothelial cells in a lymphatic vessel allows what kind of substances in?
    and where does it move to?
    small molecules (like H2O) and large substances (such as proteins, viruses, bacterial cells, cancer cells, and debris) to move from the interstitium into the lumen of the lymphatic capillary
  23. the lymphatic capillary is far more what than a blood capillary?
    lymphatic capillary is far more permeable than a blood capillary.
  24. what happens if the lymph tries to move out of the lymphatic capillary back into the interstitium?
    the endothelial cells come back together and overlap with one another, which closes off the spaces and essentially traps the lymph within the lymphatic vessel.
  25. Lymphatic capillaries converge to form what?
    larger lymphatic vessels
  26. a larger lymphatic vessel resembles the structure of what?
    what are the the 2 things that makes them different?
    resembles a vein in structure, but has a thinner wall and more valves
  27. Excess interstitial fluid (and any dissolved pathogens and debris) flows from the interstitium into the..
    and it forms what?
    lymphatic capillaries, forming lymph
  28. The lymph then moves into larger lymphatic vessels. As these larger
    lymphatic vessels course through the body, they give rise to what?
    and what does that do?
    lymph nodes, where lymph is filtered of any pathogens and debris
  29. Lymph eventually flows into the largest lymphatic vessels, what are the called?
    the right lymphatic duct and the thoracic (left lymphatic) duct.
  30. Finally, lymph moves from the right lymphatic duct and the thoracic (left
    lymphatic) duct into the..
    right and left subclavian veins, respectively
  31. The lymphatic organs include the...
    lymph nodes, the tonsils, spleen, and the thymus gland
  32. what are lymph nodes?
    small, bean-shaped masses that are located between lymphatic vessels
  33. where are lymph nodes located?
    • Single lymph nodes are found throughout the body
    • can also exist in groups; neck, armpit, and groin
  34. the lymph nodes that exist in groups, (neck, armpit, & groin) are called what?
    cervical nodes, axillary nodes, and inguinal nodes, respectively
  35. what is within a lymph nodes structure?
    and what else does it consist of?
    • reticular connective tissue
    • a. reticular fibers
    • b. macrophages
    • c. lymphocytes
  36. what are the reticular fibers that are on the structure of an lymph node?
    thin collagen fibers that interact together to form a netlike association
  37. what are the lymphocytes in a lymph node?
    both B cells and T cells
  38. what is the function of the lymph nodes?
    Lymph nodes filter the lymph of foreign substances (pathogens and debris, etc.).
  39. Lymphatic vessels bring lymph to lymph nodes. So as lymph travels through each lymph node, any foreign substances
    in the lymph are
    trapped by the netlike reticular fibers, which then allows the macrophages and lymphocytes to destroy them (like a spider that traps and then kills a fly in its web).
  40. location of our tonsils?
    located in the pharynx (throat) and the oral cavity
  41. what are the 3 types of tonsils,
    • a. pharyngeal tonsil
    • b. palatine tonsils
    • c. lingual tonsils
  42. pharyngeal tonsil
    paired or unpaired?
    • unpaired
    • also called the adenoid
    • located in wall of the nasopharynx
  43. palatine tonsils
    paired or unpaired?
    which one is more susceptible to infection, and what happens?
    • paired
    • located in the posterior end of the oral cavity
    • The palatine tonsils are most susceptible to infection and may have to be removed (tonsillectomy).
  44. lingual tonsils
    paired on unpaired?
    • paired
    • located at the base of the tongue
  45. what is the structure like for tonsils?
    tonsils consist of reticular connective tissue containing reticular fibers, macrophages, and lymphocytes.
  46. what is the function of the tonsils?
    tonsils trap and destroy any pathogens that enter the pharynx and oral cavity from inhaled air or from ingested food and beverages
  47. upon close inspection of the external structure of the tonsils reveals
    that the...
    tonsils contain invaginations (folds) that form valleys called crypts.
  48. As pathogens in air, food, or liquid interact with the tonsils, the pathogens become trapped in the crypts.By chance, the pathogens then move....
    deeper into the reticular connective tissue within the tonsils, where the macrophages and lymphocytes destroy them.
  49. spleen 
    • the largest lymphatic organ
    • located on the left side of the body between the diaphragm and the stomach
  50. structure of the spleen?
    consists of reticular connective tissue that is organized into regions called white pulp and red pulp
  51. In addition, the spleen is heavily
    • vascularized
    • splenic artery provides blood to the spleen
    • splenic vein drains it
  52. Since the spleen is so heavily vascularized, trauma to the spleen....
    can cause severe bleeding and even death
  53. trauma to the spleen can cause severe bleeding and even death. what must be done if this happens?
    he spleen must be removed (splenectomy) to stop the bleeding
  54. what are the functions of the spleen?
    • It filters the blood of pathogens
    • It destroys worn out blood cells
  55. The splenic artery brings blood to the spleen. From the splenic artery, blood eventually moves into the....
    reticular connective tissue that forms the white pulp and the red pulp
  56. (spleen) As blood moves through the white pulp and red pulp,
    lymphocytes and macrophages remove and destroy any pathogens that get caught in the reticular fibers
  57. (spleen) lymphocytes and macrophages remove and destroy any pathogens that get caught in the reticular fibers, so then the blood then moves from the white pulp and red pulp into...
    the splenic vein, which takes the filtered blood away from the spleen
  58. the filtering function of the spleen is similar to that of the...
    what is the only difference b/wn the 2?
    lymph nodes; the only difference is that the spleen filters blood, while the lymph nodes filter lymph.
  59. spleen destroys worn out blood cells. As blood is filtered in the spleen, the macrophages can
    remove and destroy any worn out blood cells via phagocytosis.
  60. what is the thymus gland
    bilobed gland that partially covers the superior portion of the heart
  61. thymus glands different sizes,
    changes with age: it is largest during infancy and childhood and gradually gets smaller as we age
  62. what is the structure of the thymus gland like?
    contains T lymphocytes (T cells)
  63. function of the thymus gland?
    promotes the maturation of T cells
  64. where are Immature T cells are initially produced?
    in the red bone marrow
  65. (thymus gland) after being produced in the red bone marrow,  these immature T cells are released into the blood
    and then...
    migrate to the thymus gland
  66. The thymus gland produces hormones called...
    & what does it do?
    thymosins that mature the T cells
  67. The mature T cells then migrate back into the blood. Some T cells patrol the blood for... 
    while others move into...
    • pathogens
    • lymphatic organs (like the lymph nodes) to fight pathogens there.
  68. what cells are produced and matured in the red bone marrow?
    because of this they do not have to migrate to the thymus gland!!
    B cells
  69. what does immunity in lymphatic system do?
    resistance to disease
  70. what are the 2 major types of immunity in the L.S?
    • nonspecific immunity
    • specific immunity
  71. what is  nonspecific immunity?
    ability to protect the body from any foreign substance in a general, nonspecific way
  72. what types of cells are involved in nonspecific immunity?
    • white blood cells
    • (neutrophils, monocytes/macrophages, eosinophils, and basophils)
  73. what is specific immunity?
    the ability to protect the body from any foreign substance in a way that involves specificity and memory
  74. specific immunity is achieved through the activities of what cells?
    • B lymphocytes and T lymphocytes (also called B cells and T cells,
    • respectively)
  75. what is difference between nonspecific immunity and specific immunity ?
    based on specificity and memory
  76. specificity
    Specific immunity targets a specific...
    pathogen (example: E. coli vs. the influenza virus)
  77. specificity
    The more specific the immune response is, the...
    easier it is to kill the invading pathogen
  78. specificity
    Nonspecific immunity is more...
    and, therefore, can target any
    type of..
    • general
    • pathogen (any type of bacterium or virus, etc.)
  79. specificity
    Nonspecific immunity
    A major disadvantage to this generalized approach is that it is...
    harder to kill a pathogen without being able to specifically target it
  80. Specific immune responses involve...
  81. memory is not associated with...
    nonspecific immunity
  82. a person often become ill upon the first exposure to a particular pathogen because..
    it usually takes time for nonspecific immunity and for specific immunity to become effective
  83. Because specific immunity involves memory, the person does
    not get sick due to a subsequent exposure to the same pathogen because the specific immunity response acts quicker this time around.
  84. Since there is no memory associated with nonspecific immunity, the nonspecific immunity response will
    still occur at the same slow pace as before and the person runs the risk of still becoming sick until the nonspecific immunity response can become effective.
  85. In order to describe specific immunity any further, one must first understand the concept of an...
  86. whats is an antigen?
    antigen is any substance that the body recognizes as being foreign (nonself) and is therefore immunogenic (promotes a specific immune response
  87. example of antigens
    Most antigens are foreign proteins:
    (what are these examples?)
    • a. the capsid (protein coat) or glycoproteins of a virus
    • b. the proteins in the cell wall and flagellum of a bacterial cell
  88. examples of antigen
    (what are the examples?)
    • -During their reproductive cycles, many plants release pollen-- a multicellular male structure that gives rise to sperm.
    • -The cell membranes of the cells in pollen contain proteins that are immunogenic in many people.
  89. examples if antigen
    certain foods
    (what are the examples?)
    The proteins found in peanuts are immunogenic in many people
  90. examples of antigen
    foreign human cells
    (what are the examples?)
    • Cells from other people contain proteins that are immunogenic
    • a. the A or B antigens in the cell membranes of the blood cells of a person that has a blood type different than yours
    • b. the MHC antigens found in nucleated cells of the tissues and organs of other people
    • -This concept will be discussed shortly.
    • c. strange proteins found in the cell membranes of cells that become cancerous in your body
    • -As a normal cell turns into a cancer cell, it produces strange proteins that the body will recognize as foreign
  91. what happens next once antigens are introduced into the body?
    B cells and T cells will find them and destroy them
  92. Note that most plastics are not
  93. since plastic is not immunogenic, it allows for what?
    they can be used to replace damaged heart valves or damaged areas of the hip or knee without fear of rejection from the body
  94. what are MHC Proteins?
  95. Our cells contain a variety of what?
  96. The majority of lipids, nucleic acids, carbohydrates, and proteins are the...
    same from person to person and, consequently, are not immunogenic to other people
  97. there is a group of proteins that is unique from individual to individual and, consequently, causes an immune response when introduced into another person
    major histocompatibility complex (MHC)
  98. what is major histocompatability complex?
    • special group of proteins found in the plasma membrane of nucleated cells
    • unique from individual to individual
    • Exception: identical twins
  99. serves as cellular “identity tags” or self-antigens
    major histocompatibility complex (MHC)
  100. what are self-antigens?
    Self-antigens are proteins that belong in one person and nobody else.
  101. The MHC complex is the basis of tissue rejections for what?
    tissue rejections during tissue or organ transplantations
  102. MHC antigens in the cells are similar to who's?
    & because they are so similar what can happen?
    • one of your close relatives
    • close relative can donate an organ to you without there being a severe immunogenic response in your body
  103. do RBCs contain MHC proteins?
    why or why not?
    • not found in RBCs
    • RBCs are non-nucleated cells; consequently, they lack MHC proteins.
  104. if RBCs do not contain MHC, then what do they contain?
    RBCs do contain their own self-antigens: the antigens of the ABO blood group and those of the Rh blood group.
  105. where and how are B & T cells produced?
    B cells and T cells are produced in red bone marrow from hemocytoblasts via the process of hematopoiesis
  106. once B & T cells are produced in the bone marrow what happens next?
    • the B cells remain in the red bone marrow for a while to undergo maturation
    • T cells do not mature in red bone marrow, they migrate to the thymus gland
  107. what happens to the T cells when they move to the thymus gland?
    T cells migrate via the blood to the thymus gland to undergo maturation there with the help of thymosins (thymic hormones)
  108. during immaturation process the T cells and the B cells become what ?
    the B cells and the T cells become immunocompetent, which is the process by which B cells and T cells develop specific antigen-binding receptors in their plasma membranes
  109. Once the maturation process has been completed, the immunocompetent B cells and T cells leave the red bone marrow and thymus gland, respectively, and migrate into what?
    and what happens?
    migrate into the blood and into the reticular connective tissue of lymphatic organs. These lymphocytes continuously travel between the blood and lymphatic organs as they patrol these areas for antigens.
  110. how many different antigens are there in the environment that could potentially cause a person to becomes sick?
    there are millions
  111. before we even encounter any of these millions antigens that could potentially make us sick what happens?
    Fortunately, the body already contains a specific B cell or T cell that can destroy each one of these antigens before you even encounter them!
  112. Hence, there are millions of different types of B cells and millions of different types of T cells in the body; each of these cells contains a specific what?
    contains a specific antigen-binding receptor in its plasma membrane
  113. yes there are millions of different types of B & T cells in our bodies BUT there are only a few what ?
    few copies of each of these different types of B cells and T cells before the initial exposure to antigens
  114. Such a small army consisting of only a few copies of each of these lymphocytes is not enough to fight a massive invasion of pathogens.As a solution to this problem, when a B cell or T cell binds to an
    antigen, it undergoes clonal selection.
  115. what is clonal selection?
    process by which a B cell or T cell divides into a clone of cells that can bind to the same antigen
  116. what is the result of clonal selection?
    results in the production of more B cells or T cells (often thousands of them) that can be used to destroy an antigen
  117. what is another result of clonal selection other than the production of more B&T cells?
    In addition, the cells of the clone become differentiated
  118. Although the differentiated cells of the clone bind to the same antigen, they function
    differently in the specific immune response that is about to occur.
  119. 1.formation of B cells
    what happens first ?
    an antigen invades the body
  120. 2. formation of B cells
    The receptor on the appropriate B cell binds to the antigen
  121. 3. formation of B cells
    The B cell is then activated by cytokines released from a helper T cell.
  122. 4. formation of B cells
    The B cell subsequently undergoes clonal selection, resulting in the production of many plasma cells and memory B cells. Both of these cell types bind to the same antigen as the original B cell.
  123. what do the plasma cells do (created by B cells)
    secrete antibodies into the blood or other body fluids
  124. antibody
    whats its role?
    • -also called an immunoglobulin (Ig)
    • -a protein that binds to and subsequently destroys an antigen
  125. antibody 
    who secretes it?
    where are they found?
    • -The antibodies secreted by the plasma cell are specific for the antigen that was recognized by the original B cell.
    • -Antibodies are found in many types of body fluids (blood , saliva, lymph, tears, mucus, breast milk, etc..)
  126. what are memory cells?
    cells that remember the antigen that caused the original B cell to undergo clonal selection
  127. Should the same antigen invade the body again, the memory B cells immediately produce what?
    more plasma cells and more memory B cells that possess the same antigen specificity.
  128. Consequently, there is a rapid production of antibodies produced by the plasma cells, which results in the quick
    destruction of the pathogen. Because the response is SOO fast..
    response is so fast that the person typically does not exhibit any signs of being ill.
  129. how long do memory B cells stay around in the body?
  130. 1. formation of T cells
    what happens?
    An antigen invades the body
  131. 2. formation of T cells
    The receptor on the appropriate T cell binds to the antigen.
  132. 3. formation of T cells
    The T cell is then activated by cytokines released from a helper T cell.
  133. 4. formation of T cells
    The T cell subsequently undergoes clonal selection, resulting in the production of many cytotoxic T cells, helper T cells, suppressor T cells, and memory T cells. All of these cell types bind to the same antigen as the original T cell
  134. cytotoxic T cells
    what are they and how do they work?
    • -also called killer T cells
    • -Cytotoxic T cells function by poking holes in the cell membrane of their target antigens, which results in cell lysis and cell death.
  135. helper T cells
    what do they do?
    what do they secrete and what does that help?
    • -activate both B cells and T cells, resulting in clonal selection
    • -Consequently, a specific immune response cannot be achieved without the helper T cells.
    • -Helper T cells activate B cells and T cells via the secretion of chemicals called cytokines (example: interleukin).
  136. what do suppressor T cells do?
    • -reduce the activity of B cells and T cells once the pathogen has been destroyed
    • -Hence, these cells only become active once the battle is over and victory has been declared
  137. what are memory T cells?
    cells that remember the antigen that caused the original T cell to undergo clonal selection
  138. if an antigen were to invade the body how would the memory T cells help?
    the memory T cells immediately produce more cytotoxic T cells, helper T cells, suppressor T cells, and memory T cells possess the same antigen specificity.
  139. memory T cells immediately produce more cytotoxic T cells, helper T cells, suppressor T cells.... so what happens tot he pathogen and how do you end up feeling?
    • the pathogen is quickly killed by the huge numbers of cytotoxic T cells.
    • This response is so rapid that the person typically does not exhibit any signs of being ill.
  140. how long do memory T cells stay around for in your body?
  141. what are the ways to acquire specific immunity? & how many are there?
    • 4
    • active natural immunity
    • active natural immunity
    • passive natural immunity
    • passive artificial immunity
  142. what is active natural immunity?
    how do you get?
    what are the signs that a person will show?
    • -specific immunity (i.e. proliferation of B cells/antibodies or T cells) that a person develops due to natural exposure to an antigen (i.e. by chance)
    • -The person will typically develop signs of illness since there has not been a previous encounter with the antigen
  143. active artificial immunity, how does a person develop it?
    specific immunity that a person develops due to deliberate exposure to an antigen by a process called vaccination
  144. what is the process of a person that is developing active artificial immunity?
    does it cause harm to the person?
    • In this process, a person receives a vaccine, which consists of an attenuated (weakened) pathogen.
    • -Since the pathogen is attenuated, it does not cause harm to the body but it is still immunogenic and will result in the production of either B cells/antibodies or T cells.
  145. what is a booster shot what is it used for?
    what immunity do you see it in the notes?
    Years after the vaccine has been administered, the person may need a booster shot to stimulate the number of memory cells in that person’s body just in case some of the previous memory cells that developed after the first vaccination.have dwindled in number.
  146. what is passive natural immunity?
    • specific immunity that develops when antibodies are passed from mother to fetus through the placenta or from mother to infant via breast milk
    • -Neither a fetus nor an infant has a well-developed immune system and, therefore, both are susceptible to frequent pathogenic invasions.
  147. what does Passive natural immunity assuresjQuery112403401908352652576_1529244672400
    that the fetus and the infant are not totally helpless.
  148. do the antibodies last forever during passive natural immunity?
    These antibodies do not last forever; they are eventually broken down and the infant will have to rely on his or her own developing immune system to provide protection.
  149. what is passive artificial immunity?
    -specific immunity that a person develops by receiving serum
  150. 1. passive artificial immunity
    Vaccinate an animal (like a horse or rabbit)
  151. 2. passive artificial immunity
    The animal’s immune system will respond to the vaccination by making antibodies in its blood.
  152. 3. passive artificial immunity
    Remove the blood from the animal and then extract the serum, which contains the antibodies.
  153. 4. passive artificial immunity
    Inject the antibodies into the person that needs immunity to provide immediate protection.
  154. which is the  preferred type of acquired immunity when there is an epidemic...consequently, there is not enough time for a person to develop his or her own specific immune response.
    Passive artificial immunity
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Chapter 5. Lymphatic System
Lymphatic System