CHAPTER 24: THE IMMUNE SYSTEM

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CHAPTER 24 THE IMMUNE SYSTEM
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THE IMMUNE SYSTEM CAN BE DIVIDED IN DIFFERENT WAYS

• SPECIFIC AND NONSPECIFIC DEFENSES
• SPECIFIC CELLS REACT AGAINST A SPECIFIC ANTIGEN
• NON SPECIFIC - REACT TO TISSUE DAMAGE AND NOT TO
  A SPECIFIC PATHOGEN
• CELLULAR VS. HUMORAL IMMUNITY
• T LYMPHOCYTES VS B LYMPHOCYTES

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NON-SPECIFIC DEFENSESNOT AGAINST A SPECIFIC
PATHOGEN

• SKIN
• PHYSICAL BARRIER TO PATHOGENS
• ACID SECRETED BY SKIN GLANDS CAN KILL MICROBES
• SWEAT, SALIVA, TEARS CONTAINS LYSOZYME AN
  ENZYME THAT KILLS BACTERIA
• DIGESTIVE AND RESPIRATORY SYSTEMS
• OPEN TO THE EXTERNAL ENVIRONMENT
• MUCOUS MEMBRANES PROVIDE PROTECTION
• STOMACH ACID CAN KILL BACTERIA
• RESPIRATORY HAIR IN NOSTRILS FILTER AIR AND
  MUCOUS IN RESPIRATORY TRACT CAN TRAP MICROBES
  CILIA CAN SWEEP BACTERIA AWAY

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OTHER NON-SPECIFIC DEFENSES

• WHITE BLOOD CELLS
• NEUTROPHILS
• MONOCYTES AND MACROPHAGES (INTERLEUKINS AND
  INFLAMMATION)
• ENGULF FOREIGN PARTICLES
• -NATURAL KILLER CELLS
• ATTACK CANCER CELLS AND OTHER CELLS THAT HAVE
  VIRUSES

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NON-SPECIFIC DEFENSES INTERFERONS

• PROTEINS MADE BY VIRUS-INFECTED CELLS HELP OTHER
  CELLS TO FIGHT OFF VIRUSES

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NON-SPECIFIC DEFENSES COMPLEMENT

• ACTIVATED BY WALLS OF BACTERIA AND FUNGI
• PUT HOLES INTO INVADERS CELL WALL
• ATTRACT WHITE BLOOD CELLS TO INFECTED AREA
• AMPLIFY THE INFLAMMATORY RESPONSE
• STIMULATE HISTAMINE PRODUCTION (PRODUCED BY WHITE
  BLOOD CELLS)

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NON-SPECIFIC DEFENSE INFLAMMATORY RESPONSE

• LOCALIZED RESPONSE OF TISSUES
• REDNESS
• SWELLING
• HOT TEMPERATURE

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STEPS IN THE INFLAMMATORY RESPONSE

• DAMAGED CELLS RELEASE HISTAMINE
• MAST CELLS

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HISTAMINE INDUCES NEIGHBORING BLOOD VESSEL TO
DILATE AND BECOME LEAKER -PHAGOCYTES (WBCs) AND
FLUID MOVE INTO THE AREAMACROPHAGES RELEASE
CYTOKINES
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• PHAGOCYTES EAT BACTERIA AND CELL DEBRIS
• TISSUE HEALS

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INFLAMMATORY RESPONSE

• LOCALIZED SINGLE SITE
• SYSTEMIC WIDESPREAD
• NUMBER OF WHITE BLOOD CELLS INCREASE
• FEVER FROM TOXINS OR FROM MEDIATORS RELEASED BY
  WBCs
• LOCAL INFLAMMATION CAN HELP HEALING BUT
  WIDESPREAD INFLAMMATION CAN BE PROBLEMATIC

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ROLE OF INFLAMMATION IN DISEASES

• MOST OF THE TIME, INFLAMMATION LETS OUR BODY
  FIGHT OFF DISEASES AND PATHOGENS
• BACTERIA
• VIRUSES
• PARASITES
• THEN, IT SUBSIDES
• SOMETIMES, IT DOES NOT SHUT DOWN AND INFLAMMATION
  BECOMES CHRONIC RATHER THAN TRANSITORY BODY
  TURNS ON ITSELF
• ROUTE OF MANY DISEASES OF MIDDLE AND OLD AGE

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INFLAMMATION CAN CONTRIBUTE TO VARIOUS DISEASES

• HEART ATTACKS
• DESTABILIZE CHOLESTEROL DEPOSITS IN CORONARY
  ARTERIES
• ALZHEIMERS DISEASE
• DESTROYS NERVE CELLS
• CANCER
• FOSTERS PROLIFERATION OF ABNORMAL CELLS
• ? INSTEAD OF DIFFERENT TREATMENTS, A SINGLE
  INFLAMMATION REDUCING REMEDY MIGHT BE ABLE TO
  PREVENT ALL THREE DISEASES

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INFLAMMATION AND CANCER

• MACROPHAGES RELEASE CYTOKINES
• MACROPHAGES AND OTHER INFLAMMATORY CELLS RELEASE
  OXYGEN FREE RADICALS
• HIGHLY REACTIVE MOLECULES
• DESTROY ABOUT ANYTHING IN THEIR PATH,
• INCLUDING DNA
• CAUSE MUTATIONS BRING IN INFLAMMATORY CELLS
  THAT SECRETE GROWTH FACTORS
• MAKE CANCER CELLS MULTIPLY EVEN MORE
• ANTI-OXIDANTS CAN HELP FIGHT OFF OXYGEN FREE
  RADICALS

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INFLAMMATION AND ALZHEIMERS DISEASE AND OTHER
NEURODEGENERATIVE DISEASES

• GLIAL CELLS COMMUNICATE AND NOURISH NEURONS
• GLIAL CELLS ARE MACROPHAGES IN THE BRAIN
• GLIAL CELLS PRODUCE INFLAMMATORY CYTOKINES THAT
  CALL OTHER IMMUNE CELLS IN
• CHRONIC GLIAL CELL ACTIVATION
• CAUSES PROBLEMS BESIDES THE INTIAL FACTORS THAT
  CAUSE THESE DISEASES

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INFLAMMATION AND AUTOIMMUNE DISEASES

• THESE DISEASES OCCUR WHEN THE BODY ATTACKS ITS
  OWN CELLS
• RHEUMATOID ARTHRITIS
• MULTIPLE SCLEROSIS
• LUPUS
• AGE
• DIRECT INFLAMMATORY ATTACK AGAINST HEALTHY CELLS
• JOINTS
• NERVES
• CONNECTIVE TISSUES

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TO LIMIT INFLAMMATION

• EXERCISE REDUCE STRESS, AMONG OTHER THINGS
• EAT
• FRUITS
• VEGATABLES
• FISH
• ANTI-OXIDANTS

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LYMPHATIC SYSTEM

• INVOLVED IN BOTH SPECIFIC AND NON-SPECIFIC
  RESISTANCE TO INFECTION
• INCLUDES
• LYMPH
• LYMPHATIC VESSELS
• LYMPH NODES
• TONSELS AND ADDENOIDS
• APPENDIX
• SPLEEN
• TWO FUNCTIONS
• RETURNS FLUID TO THE CIRCULATORY SYSTEM
• FIGHTS INFECTION

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INFECTION-FIGHTING LYMPH ORGANS IN
PINKMACROPHAGES AND LYMPHOCYTES IMPORTANT
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LYMPH NODES IMPORTANT

• LYMPHNODES SWELL DURING AN INFECTION
• CONTAIN MACROPHAGES - NONSPECIFIC IMMUNITY AND
  LYMPHOCYTES SPECIFIC IMMUNITY

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SPECIFIC IMMUNE RESPONSE

• NON-SPECIFIC DEFENSES AGAINST ANY ORGANISM
• SPECIFIC RESPONSES MUST BE PRIMED BY AN ANTIGEN
  A MOLECULE THAT GENERATES AN IMMUNE RESPONSE
• T AND B LYMPHOCYTES

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SPECIFIC IMMUNITY

• ANTIGEN
• ANTIBODY
• ACTIVE VS. PASSIVE IMMUNITY
• HUMORAL (B CELL) VS. CELL-MEDIATED IMMUNITY (T
  CELLS)
• DEVELOPMENT OF B AND T CELLS
• EFFECTOR AND MEMORY CELLS
• CLONAL SELECTION

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• ANTIGEN FOREIGN PARTICLES
• MOLECULES ON THE SURFACE OF DIFFERENT INFECTIOUS
  AGENTS OR CELLS
• DUST
• TRANSPLANTED ORGANS
• ANTIBODIES
• FOUND IN BLOOD PLASMA
• BIND TO A SPECIFIC ANTIGEN

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IMMUNITY

• RESISTANCE TO SPECIFIC INVADERS
• THE IMMUNE SYSTEM HAS A MEMORY
• THE IMMUNE RESPONSE AFTER A SECOND EXPOSURE TO AN
  ANTIGEN IS FASTER THAN THE FIRST EXPOSURE
• IMMUNITY CAN BE ACQUIRED
• NATURALLY, BY INFECTION WITH A GIVEN ORGANISM
• ARTIFICIALLY, BY VACCINATIONS
• INACTIVATED FORM OF A DISEASE CAUSING
  MICROORGANISM

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VACCINATION

• YOUR IMMUNE SYSTEM MOUNTS AN IMMUNE RESPONSE
  AGAINST THE VACCINE
• AFTER VACCINATION, WE WILL RESPOND QUICKLY WHEN
  EXPOSED TO THE NATURAL PATHOGEN

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• WHAT DISEASES DO WE HAVE VACCINES FOR?

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• SMALL POX
• POLIO
• MUMPS
• MEASLES
• HEPATITIS HEALTH CARE WORKERS
• TO SEE IF YOU ARE PROPERLY VACCINATED, YOUR
  ANTIBODY TITER IS TESTED

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ACTIVE VS. PASSIVE IMMUNITY

• ACTIVE IMMUNITY
• BODY STIMULATED TO MAKE ITS OWN ANTIBODIES
• VACCINATION OR EXPOSURE TO A PATHOGEN
• PASSIVE IMMUNITY
• PERSON IS GIVEN AN INJECTION OF ANTIBODIES OR A
  FETUS OBTAINS ANTIBODIES FROM THE MOTHER
• IMMUNITY TEMPORARY PERSON DOES NOT MAKE THEIR
  OWN ANTIBODIES

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TWO BRANCHES OF THE IMMUNE SYSTEM

• CELL MEDIATED IMMUNITY
• IMMATURE LYMPHOCYTES DEVELOP IN THE BONE MARROW
  FROM STEM CELLS
• T CELLS DEVELOP IN THE THYMUS
• B CELLS DEVELOP IN THE BONE MARROW
• CIRCULATE IN THE BLOOD AND LYMPH
• ATTACK CELLS INFECTED WITH PATHOGENS
• ATTACK CANCER CELLS
• INDIRECTLY FIGHT INFECTION
• STIMULATE OTHER WHITE BLOOD CELLS
• STIMULATE B CELLS TO MAKE ANTIBODIES
• HUMORAL IMMUNITY
• ANTIBODIES
• CAN BE PASSIVELY TRANSFERRED BY INJECTING PLASMA
  CONTAINING ANTIBODIES FROM ONE PERSON TO ANOTHER

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DEVELOPMENT OF T AND B CELLS
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ANTIGENS AND ANTIBODY BIND LIKE ENZYME AND
SUBSTRATELOCK AND KEY MECHANISM

• ANTIBODIES HAVE TWO ANTIGEN BINDING SITES
• ANTIGENS HAVE DIFFERENT ANTIGENIC DETERMINANTS
  DIFFERENT REGIONS WHERE THE ANTIBODIES CAN BIND

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CLONAL SELECTION

• BODY SELECTS FOR B CELLS THAT BIND A SPECIFIC
  ANTIGEN
• THESE CELLS REPRODUCE TO PRODUCE CLONES OF B
  CELLS THAT SECRETE A SPECIFIC ANTIBODY
• EFFECTOR CELLS ARE PRODUCED

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CLONAL SELECTION
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• IF CELLS ARE AUTOREACTIVE AND REACT AGAINST SELF
  ANTIGENS, THEY WILL BE ELIMINATED

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MEMORY RESPONSES

• PRIMARY RESPONSE
• FIRST EXPOSURE TO AN ANTIGEN
• A FEW ANTIBODIES PRODUCED CONCENTRATION LOW
• LAG FROM EXPOSURE TO ANTIBODY PRODUCTION
• SECONDARY RESPONSE
• SECOND EXPOSURE TO ANTIGEN
• NO LAG
• HIGHER TITER OF ANTIBODY FORMED
• RESPONSE LASTS LONGER

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MEMORY CELLS

• ARISE FROM LYMPHOCYTES
• CAN LAST FOR DECADES
• WHEN EXPOSED TO ANTIGEN, MAKE MORE MEMORY AND
  EFFECTOR CELLS

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SUMMARY

• PRIMARY RESPONSE
• B CELL IS SELECTED BY ANTIGEN
• SPECIFIC RECEPTORS ANTIBODIES ON THE B CELLS
  BIND WITH ANTIGENIC DETERMINANTS ON THE ANTIGENS
  SURFACE
• GROWTH, DIVISION AND DIFFERENTIATION OF THE B
  CELL
• EFFECTOR B CELLS OR PLASMA CELLS
• SMALL NUMBER OF MEMORY B CELLS
• PLASMA CELLS SECRETE ANTIBODY
• PLASMA CELLS HAVE A SHORT LIFESPAN AND WILL DIE
  OUT

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• MEMORY CELLS AWAIT FURTHER EXPOSURE TO ANTIGEN
• SECONDARY RESPONSE ENCOUNTER AN ANTIGEN SEEN
  BEFORE CAN BE YEARS
• MEMORY CELLS BIND ANTIGEN
• MORE QUICKLY PRODUCE A LARGER CLONE OF CELLS THAN
  IN THE PRIMARY RESPONSE
• ANTIBODY TITERS ARE HIGHER

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