immune system. ph=3-5 skin secretions lysozyme tears mucus, saliva

Immune System

pH=3-5•Skin•Secretions •Lysozyme

•Tears•mucus,•saliva

Mucus Membranes

Phagocytic cells

Migrate OUT of the blood when the sense differences in concentration of certain chemicals engulf bacteria, dead cells, etc….

Recognize surface molecules on abnormal cells (cancerous or virus infected)

Pin

1 2 3

SwellingSkin surface

Bacteria

Chemicalsignals

Whiteblood cell

Blood vessel

Phagocytes andfluid moveinto area

Phagocytes

Tissue injury; release ofchemical signals such ashistamine

Dilation and increasedleakiness of local bloodvessels; migration ofphagocytes to the area

Phagocytes(macrophages andneutrophils) consumebacteria and celldebris; tissue heals

link

http://www.sumanasinc.com/webcontent/anisamples/dynamicillustrations/inflammatory.html

Fig. 24-2a

Pin

1

Skin surface

BacteriaChemicalsignals

Whiteblood cell

Blood vessel

Tissue injury; release ofchemical signals such ashistamine

Fig. 24-2b

2

Swelling

Phagocytes andfluid moveinto area

Dilation and increasedleakiness of local bloodvessels; migration ofphagocytes to the area

Fig. 24-2c

3

Phagocytes

Phagocytes (macrophagesand neutrophils) consumebacteria and cell debris;tissue heals

Lymphatic system includes: -vessels (with valves)

-fluid (lymph) -organs

Important cells involved are T lymphocytes and B lymphocytes

These cells are responsible for specific immune responses to specific pathogens

•Is highly specific•Produces antibodies in response to specific antigens•Antigens may be molecules on bacteria, viruses, protozoa, worms, transplanted organs

•Both B and T lymphocytes have receptors on membrane that recognize different antigens

Acquired Immunity (the immune response)

B cells -mature in bone- produce antibodies

-antibodies float through the blood, recognizing and attaching to antigens

T cells -mature in thymus-do not produce antibodies-cytotoxic T cells - require cell/cell contact to destroy pathogen

Both B cells and T cells can produce memory cells

Fig. 24-5a

Humoral immuneresponse

Cell-mediatedimmune response

Lymph nodes,spleen, and

other lymphaticorgans

Final maturationof B and T cells inlymphatic organ

Viablood

T cellB cell

Viablood

Antigenreceptor

Thymus

Antigenreceptor

Immaturelymphocytes

Stem cell

Bonemarrow

T cells are selected

B cells are selected-antibody producing plasma cells are produced

Person feels ill while these cells are producedSymptoms diminish as these cells do their job

Response is much faster

Memory cells are activated -tend to have a stronger response than the primary

Fig. 24-7aa-1

Primary immuneresponse

B cells withdifferentantigenreceptors

Antigen receptor(antibody on cellsurface)

1

Fig. 24-7aa-2




1 Antigenmolecules

2

Fig. 24-7aa-3




1 Antigenmolecules

2

First exposureto antigen

Cell activation:growth,division, anddifferentiation

3

Fig. 24-7aa-4




1 Antigenmolecules

2



3

Antibodymolecules

EndoplasmicreticulumFirst clone

Plasma (effector) cells secreting antibodies

4

Fig. 24-7aa-5




1 Antigenmolecules

2



3

Antibodymolecules

EndoplasmicreticulumFirst clone

Plasma (effector) cells secreting antibodies

4

Memory cells

5

Fig. 24-7aa-6

Second clone

Plasma (effector) cells secreting antibodies Memory cells

6

Antigenmolecules

Second exposureto same antigen

Endoplasmicreticulum

Antibodymolecules

Secondaryimmuneresponse (Mayoccur long afterprimary immuneresponse.)

Fig. 24-12-1

1 Cytotoxic T cell bindsto infected cell

Self-nonselfcomplex

CytotoxicT cell

Foreignantigen

Perforinmolecule

Infected cell

T cells work by directly binding to infected cells and then destroying them

Fig. 24-12-2


Self-nonselfcomplex

CytotoxicT cell

Foreignantigen

Perforinmolecule

Infected cell

Perforin makes holes ininfected cell’s membraneand enzyme enters

Holeforming

2

Fig. 24-12-3


Self-nonselfcomplex

CytotoxicT cell

Foreignantigen

Perforinmolecule

Infected cell

Perforin makes holes ininfected cell’s membraneand enzyme enters

Holeforming

2 Infected cellis destroyed

3

Allergies

Hypersensitivity to environmental antigen (allergen)

Antibodies attach to mast cells - later, allergen attaches to these antibodies on mast cells

Histamine & other inflammatory agents released

Fig. 24-17a

B cell(plasma cell)

Mastcell

HistamineAntibodiesattach tomast cell

Antigenic determinant

B cells makeantibodies

Allergen (pollen grain)enters bloodstream

Sensitization: Initial exposure to allergen

1 2 3

Fig. 24-17b

Allergen binds toantibodies onmast cell

Histamine isreleased, causingallergy symptoms

Later exposure to same allergen

4 5

Anaphylactic shock

Acute reaction to allergen

Massive dilation of blood vessels-drop in blood pressure

Counteracted by epinephrine

Active immunityresults from natural recovery from infections

vaccinations

Passive immunityReceive antibodies from someone else

-IgG anitibodies cross placenta-breast milk-shots (rabies treatment)

Transfusions/transplantsABO blood group

-IgM doesn’t cross placenta

Antibodies produced against bacterial antigens which are very similar

rH factor-IgG crosses placenta

Tissue graphs/ organ transplants

Give drugs that suppress cell mediated immunity

Bone marrow transplants

Risk of graft vs host reactionDonor lymphocytes attack host cells

Autoimmune diseasesImmune system doesn’t recognize “self” and attacks

MS

Insulin dependent diabetes

HIV infection of cells require CD4-found on T cells

Is a retrovirusAntibodies are ineffective because

-provirus gives it “invisibility”-rapid rate of mutation-Helper T cells decrease-secondary infections

Drug treatments slow viral replication-AZT (reverse transcriptase inhibitors)-protease inhibitors

immune system. ph=3-5 skin secretions lysozyme tears mucus, saliva

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selectedb cells

dead cells

plasma cells

antigenst cells

fastermemory cells

b lymphocytesthese cells

pathogenboth b cells

immune responseb cells