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examples of 1st line of defense
Skin- physical barrier Saliva & tears- antimicrobial proteins) Cilia in lungs (sweep dust so it exists when you exhale) Gastric juices- (stomach acid) Good bacteria- (mutualistic) already taking up the real estate Mucus- (physically trap pathogens)
the 1st line of defense is...
a physical defense barrier
defense line 1 & 2 are...
innate (there is no adaptation to them)
Phagocytes
(macrophages & natural killer cells) AKA WBC
What do phagocytes do?
Pull pathogens cells & will stretch plasma membrane around the invader and digest it
Interferons are...
substances secreted by cells invaded by viruses that stimulate neighboring cells to produce protein for themselves
Inflammatory Response
a series of nonspecific events that occur in response to pathogens
Histamine is secreted by
WBC called basophils
Vasodilation increases
blood pressure & causes redness
what causes inflammation when vasodilation occurs?
White cells are sneaking out
Complement proteins
help the phagocytes engulf invaders
What makes it easier for WBC to escape
Increasing the size of cells (blood) make them porous
What's the 3rd line of defense against pathogens?
immune response (A part of the adaptive immune system)
does the 3rd line Targets specific antigens
yes
major histocompatibility complex (MHC) ...
distinguishes self from, non-self
primary agents of the 3rd line of defense
lymphocytes which are made in the bone marrow are stored in lymph nodes
B-cells Have antigen receptors called
antibodies (made up of 2 heavy chains & 2 light chains)
what do they produce when B-cells encounter antigens that bind to their antibodies?
2 things: Plasma cells & Memory cells
Memory cells are
long-lived B cells that do not release antibodies until the antigen is encountered in the future
Plasma cells
B-cells that release specific antibodies
humoral response
Use of antibodies to fight disease
passive immunity
Antibodies can also be given from a mother to her child prior to birth.
Artificial passive immunity
can also occur when antibodies are transferred from one individual to another by nonnatural means
T-cells are...
lymphocytes that mature in the thymus gland
Cytotoxic T-cells (killer)...
recognize & destroy specific pathogens puncturing them
Helper T-cells
stimulate the proliferation (growth) of B-cells & killer T-cell
cell mediated response
The use of T-cells to fight disease
Epidemiology
Study of the occurrence, distribution & control of disease in a population
Epidemiologist study...
how many people have a certain disease in a given time period
Epidemiologist examine...
regions of the country/world where it occurs & how its distributed
Epidemiologist determine...
best strategies to prevent the spread
How many infections are needed for an epidemic to occur?
any number larger than normal
Pandemics
world-wide infections/epidemics
Ex of pandemics
Spanish Flu in 1918, Bird Flu of 2007
What factors can lead to a pandemic? (most important)
ability to travel around the world###