THE LYMPHATIC SYSTEM

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THE LYMPHATIC SYSTEM IMMUNITY

• CHAPTER 14
• A P

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Functions

• Return tissue fluid to the blood to maintain
  blood volume
• Protect the body against pathogens and other
  foreign material

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THE LYMPHATIC SYSTEM

• Lymph
• Lymph vessels
• Lymph nodes and nodules
• Spleen
• Thymus

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LYMPH-fig 14-1

• Tissue fluid that enters the lymph capillaries
• Similar to blood plasma, but with more WBCs
  present
• This fluid must be returned to the blood in order
  to maintain blood volume and BP

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LYMPH VESSELSFIG 14-2

• Dead end lymph capillaries found in most tissue
  spaces
• Structures like veins with valves to prevent
  backflow of lymph
• Lymph is kept moving by
• constriction of the vessels
• skeletal muscle pump
• respiratory muscle pump

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LYMPH VESSELSFIG 14-3

• Lymph from the lower body and LUQ enters the
  thoracic duct and then into the left subclavian
  vein and back into the heart
• Lymph from the RUQ goes into the right lymphatic
  duct then into the right subclavian vein and back
  into the heart

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LYMPH NODES

• Masses of lymphatic tissue that produce
  lymphocytes monocytes
• Found in groups along the pathways of lymph
  vessels
• As lymph flows through them

• lymphocytes monocytes enter the lymph
• foreign materials are phagocytized by fixed
  macrophages
• fixed plasma cells produce antibodies to
  foreign antigens

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LYMPH NODES

• Major paired groups of lymph nodes are the
  cervical, axillary, inguinal groups.
• These are found at the junctions of the head
  extremities with the trunk

• Remove pathogens from the extremities before the
  lymph is returned to the blood

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LYMPH NODULES

• Small masses of lymphatic tissue found in mucous
  membranes located along natural body openings
• Peyers patches in small intestine
• Tonsils along the pharynx where food air that
  may contain pathogens pass
• The macrophages present in the nodules attack
  destroy the bacteria before they get into the
  blood

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SPLEEN

• Located in the LUQ behind the stomach
• Fetal spleen produces RBCs
• Function after birth
• production of lymphocytes monocytes
• production of antibodies
• fixed macrophages phagocytize pathogens old
  RBCs form bilirubin send to liver for
  excretion as bile

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THYMUS

• Located inferior to the thyroid gland
• Large in the fetus infant, shrinks with age
• Functions
• produces T lymphocytes
• produces thymic hormones that make T cells
  mature
• by age 2 the immune system matures becomes
  fully functional

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WHAT IS IMMUNITY?

• THE ABILITY OF THE BODY TO DESTROY FOREIGN
  ANTIGENS PREVENT FUTURE CASES OF CERTAIN
  INFECTIOUS DISEASES
• FOREIGN ANTIGENS INCLUDE BACTERIA, VIRUSES,
  FUNGI, PROTOZOA, MALIGNANT CELLS

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How Does Immunity Work?

• Antigens are chemical markers one cells that
  identify them as has self or nonself
• The immune system recognizes this launches an
  attack on the antigen by 2 mechanisms
• Innate immunity is nonspecific, always the
  same, does not create memory does not become
  more efficient with repeated exposures
• Adaptive immunity is specific, changeable, does
  create memory becomes more efficient with
  repeated exposures

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INNATE IMMUNITY fig 14-6

• Barriers
• skin
• mucous membranes of respiratory, digestive,
  urinary reproductive tracts
• lysozyme in saliva tears
• WBCs in SQ tissue

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INNATE IMMUNITY fig 14-6

• Defensive Cells
• macrophages phagocytize pathogens
• Langerhans cells of the skin also phagocytize
  pathogens
• Natural killer cells (NK cells) make direct
  contact with pathogens rupture their cell
  membranes

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INNATE IMMUNITY fig 14-6

• Chemical Defenses
• interferons proteins produced by cells
  infected by viruses
• complement a group of more than 20 plasma
  proteins that lyse cellular antigens label
  noncellular antigens for destruction
• inflammation a general response to damage of
  any kind

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ADAPTIVE IMMUNITY Fig 14-7

• Carried out by lymphocytes macrophages
• Lymphocytes
• T cells
• B cells
• The immune system must 1st recognize the antigen
  as foreign
• T cells
• B cells
• helper T cells or CD4 cells

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ADAPTIVE IMMUNITY Fig 14-7

• Cell Mediated Immunity
• Antibody Mediated Immunity

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CELL MEDIATED IMMUNITY

• No antibodies produced
• Activated T cells divide to form
• memory T cells which will remember the specific
  antigen become active if it invades the body
  again
• cytoxic (killer) T cells chemically destroy the
  foreign antigens

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ANTIGENS ANTIBODIES

• ANTIGENS
• chemical markers that identify cells
• human cells have self antigens the HLA
  types
• foreign antigens stimulate antibody production
  or other immune responses

• ANTIBODIES
• also called immune globulins or gamma globulins
• proteins produced by plasma cells in response
  to foreign antigens
• each antibody is specific for one foreign
  antigen
• bonds to foreign antigen to label it for
  phagocytosis

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Humoral or Antibody-Mediated Inmmunity

• Uses antibodies is effective against pathogens
  foreign cells
• B cells Helper T cells recognize the foreign
  antigen B cells are antigen-specific begin to
  divide
• Memory B cells will remember the specific foreign
  antigen
• Other B cells become plasma cells that produce
  antigen-specific antibodies

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Humoral or Antibody-Mediated Immunity

• An antigen-antibody complex is formed that
  attracts macrophages
• Complement fixation is stimulated by
  antigen-antibody complexes. Then complement
  proteins bind to the complex lyse cellular
  antigens enhance the phagocytosis of
  noncellular antigens
• Suppressor T cells stop the immune response when
  the foreign antigen has been destroyed

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Antibody Responses their Functions

• 1st exposure to an antigen antibodies are
  produced slowly in small amounts while the
  person may have signs of the disease
• 2nd exposure the memory cells initiate a rapid
  production of large amounts of antibodies a 2nd
  case of the disease may be prevented

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Antibody Responses and Their Functions

• The antibodies cause agglutination or clumping of
  bacterial cells clumped cells are easier for the
  macrophages to phagocytize or eat
• Antibodies neutralize viruses by bonding to them
  preventing their entry into the cells
• Antibodies neutralize bacterial toxins by bonding
  to them changing their shape

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TYPES OF VACCINES-Box 14-4

• ATTENUATED-WEAKENED ORGANISM
• TOXOID-MADE FROM TOXIN ALTERED WITH HEAT AND
  CHEMICALS
• RECOMBINANT DNA-NEWEST FORM PRODUCED FROM
  ANTIGENIC COMPONENTS OF PATHOGENS OR BY GENETIC
  ENGINEERING

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BOOSTERS

• SOME IMMUNITY DOES NOT LAST A LIFETIME
• TO HELP MAINTAIN A HIGH TITER (LEVEL) OF
  ANTIBODIES, BOOSTER SHOTS ARE GIVEN
• STATES HAVE REQUIREMENTS FOR IMMUNIZATIONS AND
  BOOSTERS FOR CHILDREN

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TYPES OF IMMUNITY

• GENETIC
• does not involve antibodies, is programmed into
  the DNA
• some pathogens affect certain host species
  not others
• Example dogs cats dont get measles, people
  dont get plant diseases

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ACQUIRED IMMUNITY

• PASSIVE antibodies from another source
• natural transmission of antibodies from mother
  to fetus via placenta or breast milk
• artificial injection of preformed antibodies
  such as gamma globulin or immune globulins after
  presumed exposure

• ACTIVE production of own antibodies
• natural recovery from a disease with production
  of antibodies memory cells
• Artificial a vaccine stimulates production of
  antibodies and memory cells