Transcript The Body at War - aiss-science-9

The Body at
War
Year 9
2010
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
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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
WORMS 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