Transcript 31 Health and Disease

Health and
Disease
Disease
• Change that disrupts the normal function
of the body (not an injury)
Disease is caused by:
• Pathogens-disease producing agents
– Bacteria- Streptococcus
– Fungi- athletes foot, nail fungus
– Worms- tapeworms, roundworms
– Viruses- HIV, Common Cold
– Protists- Plasmodium; malaria
Bacteria• Domain- Eubacteria
• Prokaryotic – NO nucleus
• Single Celled
• Has its own DNA – circular
(plasmid)
3 Shapes:
Bacilli, Cocci, and Spirilla
3
– Viruses• not a living thing
• No cell structures or processes
–Composed of: a core of DNA wrapped
in a Protein coat called a, capsid
– If they contain RNA instead, they are
called retroviruses
Pg. 479 Figure 19-9
• Types of Viruses
• Reproduce inside living cells by forcing
cell to make more viruses
• Types: Colds, warts, HIV, influenza,
smallpox
– Protists•
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Single Celled; Eukaryotes
Some are plant-like- Euglena
Some are animal-like- Amoeba
Plasmodium causes Malaria
Disease is also caused by:
•
Environmental Factors–
–
Diet- heart disease, diabetes
Carcinogens –substances known to
cause cancer- abnormal cells
divide out of control
•
tobacco products, UV Rays, radiation
skin cancer
Disease is also caused by:
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Genetic factors- hemophilia, cystic
fibrosis, PKU, sickle cell anemia
Combination of factors- cancer, diabetes
can be caused by genetic and environmental factors
Disease is spread by:
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Physical contact- touch, air, objects,
sexual contact
Contaminated food and water
Animals
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–
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Dog- rabies
Mosquitoes- malaria
Tick- Lyme disease
Fighting Infectious Disease
•
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Antibiotics- compounds that kill
bacteria but not host cells
Antivirals- compounds that fight viral
infections
Body Defenses- 3 lines of defense
–
1st Line of Defense -keeps pathogens out
of the body
•
Skin **most important nonspecific
defense**, mucus, tears, sweat,
stomach acid and saliva (contain lysozyme)
•
Not specific- attacks any invader
Fighting Infectious Disease
–
2nd Line of Defense- cells or
processes
•
Not specific- attack any
foreign invader
•
White blood cellsPhagocytosis: ingest and
digest
•
Inflammatory Resonsepain and swelling
•
Fever- increase in body
temperature; slows or
STOPS the growth of
pathogen
phagocytosis
Fighting Infectious Disease
–
3rd Line of Defense- Immune Response
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Specific for each foreign invader
Antigen-substance that triggers an immune
response
B cells– produce antibodies- proteins that circulate in
bloodstream and cause invader death
– Provide memory when same invader is
encountered again
T cells
Immune Response
– Help activate B cells
– Kill cancer or infected cells
– Suppress immune response
Types of Immunity
–
Active Immunity
•
vaccine (weakened or
dead pathogens) or
active infection
•
Stimulates immune
system to create B
cells ready to
produce specific
antibodies for the
long term
•
Chicken pox
infection, polio
vaccine
Types of Immunity
–
Passive Immunity
•
Antibodies produced elsewhere
•
Provides only short term protection
•
Mothers antibodies passed to fetus,
snake antivenom given to bite victim