Download nonspecific defense

The Lymphatic System
Function 1: to return interstitial fluid to
blood stream
Function 2: to provide working location
for immune system
IMMUNE SYSTEM
Immunity is the ability to defend against
pathogens.
Pathogen: an organism or virus that
causes disease.
ex. infectious agents, foreign cells, even
abnormal body cells (cancer).
NONSPECIFIC DEFENSE
 SKIN
keratin
 CILIA
 MUCOUS MEMBRANES
 STOMACH ACID
 RESIDENTIAL BACTERIA
 Sweat, tears, saliva have lysozyme.
INTERFERONS
 Small proteins
 Active only against viruses
 Released by invaded cell
 To “warn” neighbor cells
 Inhibit reproduction of viruses.
Inflammatory response
 Skin is cut
 Histamines released by damaged cells
 WBC’s attracted (phagocytes)
 Blood flow increased
 Capillaries permeable to phagocytes
 Phagocytes ingest pathogens by endocytosis
 Local temp rises
 Blood clot forms with platelets
 Hot, red, swollen, painful. :(
BLOOD CELLS
1 in 1000 blood cells is a leukocyte
 A. ERYTHROCYTES
 B. LEUKOCYTES
 Phagocytes
 Lymphocytes.
Phagocyte: NEUTROPHILS
 50-70% OF WBC’S
 Push thru capillaries to
phagocytize invaders
 Granules are lysosomes
with hydrolytic enzymes.
Phagocyte: BASOPHILS
 0.1% OF WBC’s
 Role in allergic reaction
 Granules have histamines
 Rupture easily.
Phagocyte: EOSINOPHILS
 1-4% of WBC’s
 Infections with parasites
 Granules have toxins.
Phagocyte: Monocytes
 Transformed into MACROPHAGES
 Ingest bacteria and viruses
 Circulate & Lodge in spleen, liver, lungs, nodes
 2-8% of WBC’s
 Activate Helper T cells (lymphocytes).
Major Histocompatability Complex
 MHC
 Class I for body cells (nucleated)
 Class II for immune cells
 20 different glycoproteins
each with 8-10 choices.
Lymphocytes:
 20 - 40% of WBC’s
 2 types:
 B (bone) cells
 T (thymus) cells
Specific defense
B lymphocytes
 Mature in the bone
 Have antigen receptors
 Produce antibodies (proteins)
 Humoral immunity
Antibody activity
 1. Coat & Clump “agglutination”
 2. Combine & Interfere “neutralization”
 3. With complement, lyse & destroy.
antibody
Clonal selection theory
of B lymphocytes
IMMUNE RESPONSE
 PRIMARY: plasma & memory cells
 SECONDARY: immediate
 Vaccinations (heat killed, weakened, close strains)
 Passive immunity versus Active immunity.
T Lymphocytes
 Mature in the thymus
 3 types
 Helper T cells (recognize Class II MHC)
 Activate B plasma cells with receptor
 Cytotoxic T cells (recognize Class I MHC)
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Attack and lyse invader
Or make clones & memory cells
Or release chemicals to attract monocytes
Or release toxins or interferons
 Supressor T cells
 turn off immune response.
Helper T Cells
Cytotoxic T Cells
Cytotoxic T-cell attacking a body cell
infected with a virus.
Central Role of Helper T Cells
Immune system
 Nonspecific:
 anatomic barriers,inflammatory, interferons
 Specific:
 Humoral with B-cells and antibodies
 Cell mediated with T-cells.
HIV - AIDS
 Human Immunodeficiency Virus
is responsible for
Acquired Immune Deficiency Syndrome
 HIV infects the helper T-cells.
 Body is vulnerable to opportunistic pathogens.
 Transmission: bodily fluids
i.e. blood, sex, breast milk, across placenta
HIV
Helper T Cell releasing HIV