the immune system. nonspecific defenses against infection include the – skin – mucous membranes...
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THE IMMUNE SYSTEM
THE IMMUNE SYSTEM
• NONSPECIFIC DEFENSES AGAINST INFECTION INCLUDE THE– SKIN– MUCOUS MEMBRANES– PHAGOCYTIC CELLS– ANTIMICROBIAL PROTEINS
THE IMMUNE SYSTEM
• NONSPECIFIC DEFENSE MEANS THAT THEY DON’T DISTINGUISH BETWEEN MICROBES– THE SKIN IS THE FIRST LINE OF DEFENSE– THE RESPIRATORY AND DIGESTIVE SYSTEMS ARE
OPEN TO THE ENVIRONMENT; LINED WITH MUCUS TO PREVENT BACTERIAS (MICROBES) FROM ENTERING
THE IMMUNE SYSTEM
• NONSPECIFIC DEFENSE MEANS THAT THEY DON’T DISTINGUISH BETWEEN MICROBES– IF MICROBES DO ENTER THE BODY CELLS OR
TISSUES THEN• NEUTROPHILS AND
MONOCYTES ATTACK FOREIGN BODY– PHAGOCYTIC CELLS
THE IMMUNE SYSTEM
• NONSPECIFIC DEFENSE MEANS THAT THEY DON’T DISTINGUISH BETWEEN MICROBES– IF MICROBES DO ENTER THE BODY CELLS OR TISSUES THEN
• NEUTROPHILS AND MONOCYTES ATTACK FOREIGN BODY– MACROPHAGES
» LARGE MONOCYTES THAT WANDER ACTIVELY THROUGH INTERSTITIAL FLUID
THE IMMUNE SYSTEM
• NONSPECIFIC DEFENSE MEANS THAT THEY DON’T DISTINGUISH BETWEEN MICROBES– IF MICROBES DO ENTER THE BODY CELLS OR TISSUES
THEN• NEUTROPHILS AND MONOCYTES ATTACK FOREIGN BODY
– NATURAL KILLER CELLS ATTACK CANCER CELLS AND INFECTED BODY CELLS
– INTERFERONS PROTEINS PRODUCED BY VIRUS-INFECTED CELLS THAT HELP OTHER CELLS RESIST VIRUSES (VIRUS INFECTION ACTIVATES INTERFERON GENE)
– COMPLEMENT PROTEINS COAT SURFACES OF MICROBES TO EASE PHAGOCYTOSIS, CUT HOLES IN MICROBE MEMBRANE, OR AMPLIFY INFLAMMATORY RESPONSE
THE IMMUNE SYSTEM
• THE INFLAMMATORY RESPONSE MOBILIZES NONSPECIFIC DEFENSE FORCES
THE IMMUNE SYSTEM
• INFLAMMTORY RESPONSE– MAJOR COMPONENT OF OUR NONSPECIFIC DEFENSE
SYSTEM– DAMANGED CELLS RELEASE CHEMICAL ALARM SIGNALS
LIKE HISTAMINE• DILATES THE BLOOD VESSELS MAKING THEM LEAKIER
– CHEMICALS SPARK THE MOBILIZATION OF VARIOUS DEFENSES
– THE WHITE BLOOD CELLS GATHERED IN THE AREA ENGULF THE BACTERIA AND THE REMAINS OF ANY DAMAGED OR DEAD CELLS
THE IMMUNE SYSTEM
• INFLAMMATORY RESPONSE– HELPS PREVENT SPREAD OF INFECTION BY
RELEASING CLOTTING FACTORS– INFLAMMATORY RESPONSE MAY BE LOCALIZED
OR WIDESPREAD (EX. FEVER)– WIDESPREAD INFLAMMATION CAN BE
DANGEROUS• SEPTIC SHOCK BACTERIAL INFECTION THAT BRINGS
ABOUT OVERWHELMING INFLAMMATORY RESPONSE
THE IMMUNE SYSTEM
• THE LYMPHATIC SYSTEM BECOMES A CRUCIAL BATTLEGROUND DURING INFECTION
THE IMMUNE SYSTEM
• LYMPHATIC SYSTEM– CONSISTS OF A BRANCHING NETWORK OF
VESSELS, NUMEROUS LYMPH NODS (SAC-LIKE ORGANS PACKED WITH THE WHITE BLOOD CELLS CALLED LYMPHOCYTES), THE TONSILS AND ADENOIDS, THE APPENDIX AND THE SPLEEN
THE IMMUNE SYSTEM
• LYMPHATIC SYSTEM– ALSO INCLUDES THE BONE MARROW AND THYMUS
(SITES WHERE WHITE BLOOD CELLS DEVELOP)– 2 MAIN FUNCTIONS
• RETURN TISSUE FLUID TO THE CIRCULATORY SYSTEM• FIGHT INFECTION
– LYMPH• FLUID CARRIED IN THE LYMPATHIC VESSELS; SIMILAR TO
INTERSTITIAL FLUID BUT LESS OXYGEN AND NUTRIENTS
– **SWOLLEN GLANDS ARE THE RESULT OF LYMPH NODES MAKING EXTRA LYMPHOCYTES TO FIGHT INFECTION
THE IMMUNE SYSTEM
• THE IMMUNE RESPONSE COUNTERS SPECIFIC INVADERS– IMMUNE SYSTEM RECOGNIZES AND DEFENDS
AGAINST INVADING MICROBES AND AGAINST CANCER CELLS
– ANTIGEN A MOLECULE THAT ELICITS AN IMMUNE REPONSE
– ANTIBODY A PROTEIN FOUND IN BLOOD PLASMA THAT ATTACHES TO ONE PARTICULAR KIND OF ANTIGEN AND HELPS COUNTER ITS EFFECTS
THE IMMUNE SYSTEM
• THE IMMUNE RESPONSE COUNTERS SPECIFIC INVADERS– IMMUNE SYSTEM HAS A REMARKABLE
“MEMORY”; ONCE IT ENCOUNTERS AN ANTIGEN IT REMEMBERS IT AND CAN COMBAT IT VERY QUICKLY
– IMMUNITY RESISTANCE TO SPECIFIC INVADERS
THE IMMUNE SYSTEM
• IMMUNITY RESISTANCE TO SPECIFIC INVADERS– CAN BE ACQUIRED NATURALLY OR BY VACCINATION
• VACCINE HARMLESS VARIANT OF A DISEASE-CAUSING MICROBE– STIMULATES
THE IMMUNESYSTEM TOMOUNTDEFENSESAGAINST THEVARIANT
THE IMMUNE SYSTEM
• IMMUNITY– 2 FORMS• ACTIVE IMMUNITY
– BODY IS STIMULATED TO PRODUCE ITS OWN ANTIBODIES
• PASSIVE IMMUNITY– BODY IS GIVEN ANTIBODIES (NOT PERMANENT!!)
» EXAMPLES INCLUDE:FETUS GETS FROM MOTHER; A DIRECT SHOT OF ANTIBODIES
THE IMMUNE SYSTEM
• LYMPHOCYTES MOUNT A DUAL DEFENSE– LYMPHOCYTES
• WHITE BLOOD CELLS THAT SPEND MOST OF THEIR TIME IN THE TISSUES AND ORGANS OF THE LYMPATIC SYSTEM
THE IMMUNE SYSTEM
• B CELLS– ARISE FROM IMMATURE LYMPHOCYTES THAT
DEVELOP IN THE BONE MARROW– GIVE RISTER TO
HUMORAL IMMUNITY• IMMUNITY
OCCURING IN THE BODY FLUIDS
THE IMMUNE SYSTEM
• T CELLS– ARISE FROM IMMATURE LYMPHOCYTES THAT DEVELOP
IN THE THYMUS– GIVE RISE TO CELL-MEDIATED IMMUNITY
• ATTACKS INFECTED CELLS
• ANTIGEN RECEPTORS– MOLECULES
CAPABLE OF BINDING TO A SPECIFIC TYPE OF ANTIGEN
THE IMMUNE SYSTEM
• CLONAL SELECTION MUSTERS DEFENSIVE FORCES AGAINST SPECIFIC ANTIGENS– CLONAL SELECTION• ATTACHMENT OF AN
ANTIGEN TO A SPECIFIC LYMPHOCYTE CAUSES MULTIPLICATION OF THAT LYMPHOCYTES VIA MITOSIS
THE IMMUNE SYSTEM
• THE INITIAL IMMUNE RESPONSE RESULTS IN A TYPE OF “MEMORY”– IT TAKES TWO EXPOSURES TO AN ANTIGEN TO
MOUNT THE STRONGEST IMMUNE RESPONSE
THE IMMUNE SYSTEM
• THE INITIAL IMMUNE RESPONSE RESULTS IN A TYPE OF “MEMORY”– PRIMARY IMMUNE RESPONSE
• OCCURS WHEN LYMPHOCYTES ARE FIRST EXPOSED TO AN ANTIGEN AND FORM A CLONE OF EFFECTOR CELLS
– SECONDARY IMMUNE RESPONSE• AFTER PRIMARY; SECOND EXPOSURE ELICITS FASTER,
STRONGER RESPONSE
– MEMORY CELLS• MADE AT SAME TIME AS EFFECTOR CELLS; DIFFER IN
STRUCTURE AND FUNCTION; MAY LAST FOR DECADES
THE IMMUNE SYSTEM
• OVERVIEW: B CELLS ARE THE MAIN WARRIORS OF HUMORAL IMMUNITY– PLASMA CELLS
• ANOTHER NAME FOR EFFECTOR B CELLS, THE ONES PRODUCING ANTIBODIES
• ANTIBODIES ARE THE WEAPONS OF HUMORAL IMMUNITY– ANTIBODY HAS 2 RELATED FUNCTIONS
• RECOGNIZE AND BIND TO CERTAIN ANTIGENS• ASSIST IN NEUTRALIZING THE ANTIGEN
– ANTIGEN-BINDING SITE• REGION OF THE MOLECULE RESPONSIBLE FOR THE ANTIBODY’S
RECOGNITION-AND-BINDING FUNCTION
THE IMMUNE SYSTEM
• ANTIBODIES MARK ANTIGENS FOR ELIMINATION– ANTIBODIES BIND TO FORM ANTIBODY-ANTIGEN
COMPLEX WHICH ALLOWS FOR ANTIGEN DESTRUCTION
THE IMMUNE SYSTEM
• MONOCLONAL ANTIBODIES ARE POWERFUL TOOLS IN THE LAB AND CLINIC– MONOCLONAL ANTIBODIES• ALL THE CELLS PRODUCING
THE ANTIBODIES ARE DESCENDANTS OF A SINGLE CELL AND THEREFORE ARE IDENTICAL• GREAT PROMISE IN
MEDICINE AND RESEARCH
THE IMMUNE SYSTEM
• T CELLS MOUNT THE CELL-MEDIATED DEFENSE AND AID HUMORAL IMMUNITY– 2 MAIN KINDS OF T CELLS
THE IMMUNE SYSTEM
• T CELLS MOUNT THE CELL-MEDIATED DEFENSE AND AID HUMORAL IMMUNITY– 2 MAIN KINDS OF T CELLS• CYTOTOXIC T CELLS
– ATTACK BODY CELLS THAT ARE INFECTED WITH PATHOGENS
• HELPER T CELLS– HELP ACTIVATE CYTOTOXIC
T CELLS AND MACROPHAGES,EVEN HELP STIMULATE B CELLSTO PRODUCE ANTIBODIES
THE IMMUNE SYSTEM
• T CELLS MOUNT THE CELL-MEDIATED DEFENSE AND AID HUMORAL IMMUNITY– CYTOTOXIC T CELLS
• ATTACK BODY CELLS THAT ARE INFECTED WITH PATHOGENS• CTYOTOXIC T CELLS BIND TO ANTIGEN• WHEN BOUND IT CAUSES THE PRODUCTION OF PERFORIN
– PROTEIN THAT CUTS HOLES IN MEMBRANE– ALLOWS OTHER
PROTEINS TO ENTER AND CAUSE DEATH OF ANTIGEN
THE IMMUNE SYSTEM
• T CELLS MOUNT THE CELL-MEDIATED DEFENSE AND AID HUMORAL IMMUNITY– CYTOTOXIC T CELLS• MAY HELP PREVENT CANCER• MONITOR CELLS AND DESTROY CANCEROUS ONES• IT’S A MYSTERY
WHY THEYSTOP WORKING
THE IMMUNE SYSTEM
• T CELLS MOUNT THE CELL-MEDIATED DEFENSE AND AID HUMORAL IMMUNITY– HELPER T CELLS• HELP ACTIVATE CYTOTOXIC
T CELLS AND MACROPHAGES,EVEN HELP STIMULATE B CELLSTO PRODUCE ANTIBODIES
THE IMMUNE SYSTEM
• THE IMMUNE SYSTEM DEPENDS ON OUR MOLECULAR FINGERPRINTS– MAJOR HISTOCOMPATIBILITY COMPLEX (MHCs)• GROUP OF SELF-PROTEIN GENES• PROTEINS FOUND ON OWN CELLS; MARK THEM AS
“OFF-LIMITS” TO IMMUNE SYSTEM
THE IMMUNE SYSTEM
• MALFUNCTION OR FAILURE OF THE IMMUNE SYSTEM CAUSES DISEASE– AUTOIMMUNE DISEASES• RESULTS WHEN THE IMMUNE SYSTEM GOES AWRY
AND TURNS AGAINST THE BODY’S OWN MOLECULES (EXAMPLE = LUPUS)
THE IMMUNE SYSTEM
• MALFUNCTION OR FAILURE OF THE IMMUNE SYSTEM CAUSES DISEASE– IMMUNODEFICIENCY DISEASES• LACK ONE OR MORE COMPONENTS OF THE IMMUNE
SYSTEM, AND ARE SUSCEPTIBLE TO INFECTIONS THAT ORDINARILY WOULD NOT CAUSE A PROBLEM (EXAMPLE = HODGKIN’S; AIDS)
THE IMMUNE SYSTEM
• ALLERGIES ARE OVERREACTIONS TO CERTAIN ENVIRONMENTAL ANTIGENS– ALLERGIES• ABNORMAL SENSITIVITIES TO ANTIGENS IN OUR
SURROUNDINGS
THE IMMUNE SYSTEM• ALLERGIES ARE OVERREACTIONS TO CERTAIN ENVIRONMENTAL
ANTIGENS– ALLERGENS
• ANTIGENS THAT CAUSE ALLERGIES
– MAST CELLS• NORMAL BODY CELLS THAT PRODUCE HISTAMINE AND OTHER CHEMICALS THAT
TRIGGER THE INFLAMMATORY RESPONSE
– ANTIHISTAMINES• DRUGS THAT INTERFERE WITH HISTAMINE’S
ACTION AND GIVE TEMPORARY RELIEF FROM AN ALLERGY
– ANAPHYLACTIC SHOCK• VERY SEVERE (POSSIBLY FATAL) ALLERGIC
REACTION• CAN BE COUNTERED WITH AN INJECTION OF
EPINEPHRINE (ADRENALINE)
THE IMMUNE SYSTEM
• AIDS LEAVE THE BODY DEFENSELESS– HIV DESTROYS THE HELPER T CELLS; TURNING OFF
HUMORAL AND CELL MEDIATED IMMUNE RESPONSES
– LEAVES THE BODY DEFENSELESS AND OPEN TO OPPORTUNISTIC INFECTIONS
– AIDS DOESN’T KILL, OPPORTUNISTIC INFECTIONS DUE
THE IMMUNE SYSTEM
• SOME THINGS THAT ARE BAD FOR US; OR THAT ARE NOT SUPPOSED TO BE INSIDE OF US, ARE THE RESULT OF CHEMICAL (METABOLIC) REACTIONS IN OUR CELLS…OUR IMMUNE SYSTEM CAN’T BE RESPONSIBLE FOR THESE
• WE NEED THE EXCRETORY SYSTEM!!!