Download Communicable Diseases:

Communicable Diseases:
Diseases that are spread from
one person / animal to
another.
Germs/Microorganisms/
Pathogens:
Tiny living creatures that
cause disease.
Bacteria
Most common of all pathogens
100 million will fit on a grain of sand
Most do not cause disease
Reproduces through cell division
Treated with antibiotics
Examples of diseases caused by
bacteria: strep throat, gonorrhea, Lyme
disease, MRSA (Methicillin-Resistant
Staphylococcus aureus).
Deer Tick
http://www.lymedisease.org/lyme101/preven
tion/lyme_prevention.html
Strep Throat
Virus
All viruses are considered parasites
Smallest and simplest of all pathogens
Can only live in living cells – tricks human
cells to reproduce more viruses
(reproduce every 20 minutes)
Reproduce until “cell bust”
Examples: chicken pox, cold, flu, measles,
rabies, HIV/AIDS
Cell Bust
http://www.youtube.com/watch?feature=end
screen&v=Rpj0emEGShQ&NR=1
Virus:
http://video.nationalgeographic.com/video/n
ews/history-archaeology-news/swine-fluoverview-vin/
Viruses attack certain parts
of the body
Rabies – brain
Polio – central nervous system (CNS)
Chicken Pox, Mumps – skin
Cold/Flu – respiratory system
Protozoa
Most are harmless
One celled organisms
Grows in water
Multiplies very quickly in moist places
Examples: diarrhea, malaria
http://www.youtube.com/watch?v=6MU7Sxz
wMVo
Fungi
Saprophytes- meaning that they live off of
non-living things
One celled or multi-cellular plants such as
yeasts, molds & mushrooms
Live in warm, moist places
examples: athlete’s foot and ringworm
Athlete’s Foot
Fungi
Athlete’s Foot
Ring Worm
Body’s Defense Against
Communicable Diseases
1. Skin- most important, it keeps out most
harmful germs, produces sweat that kills
some type of pathogens (germs).
2. Mucus Membrane- cells that line the
nose, throat and mouth. They produce
mucus to trap harmful germs so they do
not enter the body.
Body’s Defense Against
Communicable Diseases
3. Cilia- tiny hairs that move in a wavelike
motion to sweep out harmful
microorganisms.
4. Fever- normal body temperature is 98.6.
Your body raises its temperature to slow
down the multiplication of
microorganisms.
Body’s Defense Against
Communicable Diseases
5. White Blood Cells- cells in your body that
fight infection. They kill pathogens by
surrounding them and swallowing them.
6. Chemical Barriers- tears and saliva.
7. Reflexes- blinking, coughing, and
sneezing.
Mucus
Membrane
Reflexes
White Blood
Cells
Cilia
Body’s
Defense
Chemical
Barriers
Fever
Skin
Ways that disease enters the body
Mouth
Eyes
Nose
Ears
Break in Skin
Genitals
How Microorganisms are Spread
Direct Contact: touching an infected area
of another person.
Indirect Contact: sneezing, coughing,
sharing personal items.
Contact with Animals: insect bites, dog
bite, bat bite.
Other Contact: eating contaminated food.
White blood cells
Many different white blood cells work together to
protect us against disease-causing germs.
Macrophages:
When a germ invades our bodies, macrophages gobble up
the germ and display its surface shape, or antigen, for other
immune cells to see.
Helper T cells: direct the defense by spotting the
foreign antigen on the macrophage and begin to multiply.
They alert other white blood cells and direct the body's
defense.
B cells: make chemicals called antibodies. Antibodies
lock onto foreign antigens making it easier for other
immune cells to destroy them.
Killer T cells: Alerted by helper T cells, killer T cells
multiply and destroy the invading germs.
Definitions
Vaccine: medicine that contains weakened
or dead pathogens that cause a certain
disease.
Antibiotic: substance used to kill/control
infectious disease by prescription.
Antiseptics: chemicals used to kill germs
on contact.