Diseases Disease Any malfunction of the body genetic

Diseases

Disease • Any malfunction of the body genetic or developmental errors, infection, poisons, nutritional deficiency or imbalance, toxins, or unfavorable environmental factors

Infectious – caused by germs • Germs – bacteria, viruses, protozoa, fungi, small animals Viruses bacteria fungi roundworms flatworms

Communicable • Can be spread from 1 organism to another Direct contact Indirect contact Airborne Contaminated food / water Animal bites

Direct Contact • Touching an infected person Shaking hands High five

Indirect Contact • Touching an object that an infected person has touched

Contamination “flu-fiction” • Movie clip

Air born • Travel through the air – effect respiratory system Cold viruses in droplets can be transmitted to a person as far as 15 feet away

Animal Bites

Malaria • Transmitted by mosquitoes

Bubonic plague • Spread by fleas buboes

Lyme disease • Spread by ticks

Rabies • A virus found in saliva of mammals such as dogs or squirrels

Contaminated Food and Water

Amoebic dysentery • caused from contaminated water

Salmonella • eating raw or undercooked foods

Botulism • improperly canned foods Serious cases can cause death from heart or respiratory failure

If germs are everywhere, why aren’t we always sick?

Body’s Defenses 1 st Line 2 nd Line 3 rd Line

1 st line – structural defense • Examples – skin Large barrier covers both outside and inside organs

• Examples – tears Contain enzymes that kill bacteria, excessive tears help wash out foreign substances

• Examples – mucus

• Examples – stomach acids

2 nd Line – cellular defense

White blood cells • Engulf the germ

Fever • Body temp. rises, slows bacterial growth

3 rd Line – chemical defense

Interferon • Chemical released from infected cells, helps protect surrounding cells

Antibodies • Proteins from white blood cells that destroy or immobilize foreign bodies

Immunity – resistance to a disease

How do you get immunity?

Inborn – genetic, born with it

Acquired – get it after you’re born

Get disease • Some antibodies stay in body to fight future germs

Vaccination • Dead or weakened germ injected into person to trigger immunity

Serum Shot • Blood plasma from immune animal injected to fight germs in another animal

Antibiotics • Chemicals from living things that kill or slow down growth of bacteria

Chemotherapy • Inorganic chemicals that kill germs