The Body at War

Year 92012

Introduction

• Health: – A state of physical, mental and social well-being.

• Disease:– Said to be present in the body when a part of it

doesn’t function normally or properly.

VIRUS:

• So small they can only be seen with an electron microscope.

• They are not considered to be living things as they do not self-reproduce, grow, feed or produce waste.

• They move from place to place, but only if they hitch a ride on something: other organisms, wind or water.

VIRUS:

• They are not cells.• They are parasitic invaders made of DNA

coated in protein.• They attach to a host cell and take it over. • They hijack the cell and reprogram it to make

more virus particles. • Eventually there are so many virus particles

that the cell breaks open and releases the virus particles which then invade other cells.

VIRUS

• They are hard to treat because they are not cells and cannot be stopped by antibiotics.

• With most viral infections, you have to wait until your body uses its own defenses to stop and kill the invading virus.

VIRUS examples

• Warts

http://virus.stanford.edu/papova/2000/papova/virus1.html

VIRUS examples

• Rubella

http://www.nlm.nih.gov/medlineplus/ency/imagepages/1315.htm

VIRUS examples

• Influenza• Common cold• Polio• AIDS

BACTERIA• Identified by their shape. They can be rod-shaped (bacilli),

spiral (spirilla) or spherical (cocci).

http://en.wikipedia.org/wiki/Bacterial_shape

BACTERIA

• All bacteria consist of ONE CELL, but they join together to form pairs, chains or clusters.

• Bacteria can multiply very quickly under the right conditions.

• Bacteria can remain inactive for days or even years.

• Many types of bacteria can be killed using penicillin or other types of antibiotics.

BACTERIA examples

• Strep throat

http://www.nlm.nih.gov/medlineplus/ency/imagepages/19694.htm

BACTERIA examples

• Tetanus• Pneumonia• Food poisoning

FUNGI

• Many fungi are parasites that feed on living plants and animals.

• This often results in a disease.• Fungi commonly invade hair, nails and skin.• Fungi are opportunistic pathogens – they are

not usually associated with infection, but will infect a person if there are ideal conditions or if their immune system is weakened.

FUNGI examples

• Tinea (athlete’s foot)

http://www.lib.uiowa.edu/hardin/mD/cdc/4803.html

FUNGI examples

• Ringworm

http://www.lib.uiowa.edu/Hardin/MD/cdc/2938.html

WORMS

• A type of parasite• Depend on their host for food

WORMS example

• Tapeworms• Can measure up to 10 meters in length.

Internal parasites found in the intestines.

http://www.ndpteachers.org/perit/biology_image_gallery1.htm

INSECTS example

• Lice• External• Thrive on human blood by biting into the skin

of their host.

http://schoolipm.ifas.ufl.edu/graphics/lice_c.htm

PROTOZOA

• Diseases caused by protozoa (protisis) are often seen in tropical/subtropical areas.

• Single-celled• Most protozoa are harmless to humans, but

some parasitic times can cause serious illness.• Sometimes form cysts around themselves if

conditions are unfavorable so they can survive between outbreaks

PROTOZOA

• Can contaminate water supplies• Ex. plasmodium is a parasitic protozoan that

lives in red blood cells and liver cells and causes malaria.

• Amoebic dysentery • African sleeping sickness