Presentation on theme: "“Fighting the Enemy Within”"— Presentation transcript:
1 “Fighting the Enemy Within” phagocytic leukocyte“Fighting the Enemy Within”Immune Systemlymphocytesattackingcancer celllymphsystem
2 Why an immune system? Attack from the outside & inside lots of organisms want you for lunch!we are a tasty vitamin-packed mealcells are packages of proteins, carbohydrates & fatsno cell wallanimals must defend themselves against invadersvirusesHIV, flu, cold, measles, chicken pox, SARSbacteriapneumonia, meningitis, tuberculosisfungiyeastprotistsamoeba, Lyme disease, malariacancer cellsabnormal body cellsWhat’s for lunch?!
3 How are invaders recognized? Antigenschemical name tags on the surface of every cell“self” vs. “invader”one of your own cellsdisease-causing virusdisease-causing bacteriaantigens say: “I belong here”antigens say: “I am an invader”antigens say: “I am an invader”
4 Non-specific patrol (passive) Immune system (active) Lines of defense1st line:broad, external defense“walls & moats”skin & mucus membranes2nd line:broad, internal defense“patrolling soldiers”phagocyte (eating) WBCs3rd line:specific, acquired immunity“elite trained units”lymphocyte WBCs & antibodiesB & T cellsBarriersNon-specific patrol (passive)Immune system (active)
6 2nd: Generalist, broad range patrols Passive immunityPatrolling white blood cellsattack invaders that get through the skinrecognize invader by reading antigensurface name tagphagocyte cellsmacrophages“big eaters”Macrophage “eating” bacteria
7 2nd “circulatory” system Production of white blood cells & traps “foreign” invadersLymph systemlymph vessels(intertwined amongst blood vessels)2nd “circulatory” systemlymph node
8 Why do injuries swell? Inflammation injured cells release chemical signalshistaminesincreases blood flowbrings more white blood cells to fight bacteriabrings more red blood cells & clotting factors to repairBlood clotPin or splinterSwellingBacteriaChemicalalarm signalsPhagocytesBlood vessel
9 Fever When a local response is not enough full body response to infectionraises body temperaturehigher temperature helps in defenseslows growth of germshelps macrophagesspeeds up repair of tissuesCertain bacterial infections can induce an overwhelming systemic inflammatory response leading to a condition known as septic shock.Characterized by high fever and low blood pressure, septic shock is the most common cause of death in U.S. critical care units.Clearly, while local inflammation is an essential step toward healing, widespread inflammation can be devastating.
10 3rd line: Lymphocytes Active immunity Specific defense B cellActive immunitySpecific defenseresponds to specific invadersrecognizes specific foreign antigenswhite blood cellsB cells & antibodiesT cells
11 B cells & antibodies B cells Patrolling B cells Memory B cells white blood cells that attack invaders in bloodmature in Bone marrowPatrolling B cellsmake antibodies against invader immediatelyMemory B cellsremembers invadercan make antibodies quickly the next timeprotects you from getting disease more than once
12 AntibodiesProteins made by B cells that tag invaders in the blood so macrophages can eat themtag says “this is an invader” gotcha!biological “handcuffs”antibody attaches to antigen on invaderYinvading germs tagged with antibodiesB cells releasing antibodiesYYmacrophage eating tagged invaders
13 Vaccinations Exposure to harmless version of germ (pathogen) stimulates immune system to produce antibodies to invaderrapid response if future exposureMost successful against viral diseases
14 Protecting you from disease Vaccinationsadvantagedon’t get illnesslong term immunityproduce antibodies for lifeworks against many viruses & bacteriadisadvantagenot possible against all invadersBreastfeedingmother’s milk gives baby antibodies & keeps baby healthy`IMPORTANT PROTECTIONantibodies pass from mother to baby in breast milk
15 You need trained assassins to kill off these infected cells! What if the attacker gets past the B cells in the blood & infects some of your cells?You need trained assassins to kill off these infected cells!TAttack of the Killer T cells!
16 T cells T cells mature in Thymus Helper T cells Killer T cells sounds the alarm for rest of immune systemKiller T cellsdestroys infected body cellsMemory T cellsremembers invader & reacts against it again quicklyWhere’s that?
17 Attack of the Killer T cells Destroys infected body cellsT cell binds to invaded cellsecretes perforating proteinpunctures cell membrane of infected cellcell burstsKiller T cellvesiclePerforin punctures cell membranecell membranecell membraneinvaded cell
18 Immune response Y Y invader skin skin invaders in body invaders in bloodinvaders infect cellsmacrophagesB cellshelper T cellsT cellsplasma B cellsmemory B cellsmemory T cellskiller T cellsYantibodiesYantibodies
19 Diseases of the immune system HIV: Human Immunodeficiency Virusinfects helper T cellshelper T cells can’t activate rest of immune systembody doesn’t hear the alarmAIDS: Acquired ImmunoDeficiency Syndromeinfections by opportunistic diseasesdeath usually from other invading diseases or cancer
21 Protecting you from disease Antibiotics = medicineadvantagekill bacteria that have successfully invaded youmake you well after being sickdisadvantageuse only after sickonly good against bacteriapossible development of resistance by bacteria (if don’t use correctly)can get sick again
22 Immune system malfunctions Auto-immune diseasesimmune system attacks own cellslupusantibodies attack many different body cellsrheumatoid arthritisantibodies causing damage to cartilage & bonediabetesbeta-islet cells of pancreas attacked & destroyedmultiple sclerosisT cells attack myelin sheath of brain & spinal cord nerves
23 Immune system malfunctions Allergiesover-reaction to harmless compoundsallergensproteins on pollenproteins from dust mitesproteins in animal salivabody mistakenly thinks they are attackers