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

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Bacteria- • Domain- Eubacteria• Prokaryotic – NO nucleus• Single Celled• Has its own DNA – circular (plasmid)

3 Shapes: Bacilli, Cocci, and Spirilla

– 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- • 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:• 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:

• Physical contact- touch, air, objects, sexual contact

• Contaminated food and water

• Animals– Dog- rabies– Mosquitoes- malaria– Tick- Lyme disease

Fighting Infectious Disease

• AntibioticsAntibiotics- compounds that kill bacteria but not host cells

• AntiviralsAntivirals- 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 lysozymecontain lysozyme)

• Not specific- attacks any invader

Fighting Infectious Disease– 2nd Line of Defense- cells or

processes• Not specific- attack any

foreign invader• White blood cells-

Phagocytosis: ingest and digest

• Inflammatory Resonse-pain and swelling

• Fever- increase in body temperature; slows or STOPS the growth of pathogen

phagocytosis

Fighting Infectious Disease– 3rd Line of Defense- Immune Response

• 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– Help activate B cells– Kill cancer or infected cells– Suppress immune response

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