The Body at War Year

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

VIRUS examples Rubella

VIRUS examples Influenza Common cold Polio AIDS

BACTERIA Identified by their shape. They can be rod-shaped (bacilli), spiral (spirilla) or spherical (cocci).

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

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)

FUNGI examples Ringworm

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.

WORMS example Lice External Thrive on human blood by biting into the skin of their host.

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