Download Disease Class Notes

Disease Class Notes
Types of Diseases
1. Non-Communicable: an illness that
is caused by something other than
a pathogen. (ex.?)
2. Chronic Disease: an illness that
persists for a long time or is
reoccurring in nature. (ex.?)
3. Communicable: an illness caused
by a pathogen that can spread
from living being to another. (ex.?)
Disease Causing Pathogens
• Bacteria: single celled
microorganisms.
• Virus: the smallest
known type of infectious
agent.
• Rickettsiae: pathogens
that grow inside living
cells and resemble
bacteria. Found in
intestinal tracts of
animals.
• Fungi: simple
organisms that cannot
make their own food
and prefer dark, damp
environments.
Examples include:
yeast or molds.
• Protozoa: tiny singlecelled organisms that
produce toxins that
cause disease.
• Parasitic Worms: an
organism that lives in or
on another organism
and benefits from living
off of the host.
Disease Transmission
• People: Diseases are spread through direct or indirect
contact with an infected person.
– Direct contact- Direct physical contact. Sexually transmitted
diseases, bites, pregnancy.
– Indirect contact- Bacteria and viruses can enter the body
through lungs. Coughing and sneezing.
• Animals: Bites. Examples – dogs can spread rabies
which can be fatal. Mosquitos can pass Malaria.
• Contaminated objects: An uninfected person touches
an object an infected person used. Example- glasses,
eating utensils, toothbrushes, needles.
• The environment: Food, water, soil, and air can contain
pathogens. Some are caused by human negligence,
for example, dumping toxic waste, careless handling of
food.
Body’s Natural Defenses:
1. Skin: unbroken skin helps prevent pathogens
from entering the body.
2. Tears, Saliva + Perspiration: chemical barriers
that can destroy bacteria. They can cause body
changes that help cells inside the body, fight
infection.
3. Mucous Membranes: the soft, skin like lining of
many parts of the body. They are in your mouth,
nose, and bronchial tubes.
4. Stomach Acids: chemical juices that destroy
pathogens that are swallowed with food.
5. Fever: abnormally high body temp. accompanied
by possible shivering and headaches.
Immune System Response
• Immune System: the
body system that
contains cells and
organisms that fight
disease.
• Phagocytes: white
blood cells that
surround + kill
pathogens by ingesting
them.
• Lymphatic System:
drains fluid back into
the bloodstream + fights
infection.
• Lymphocytes: white blood
cells that protect the body
against pathogens.
• Lymph Nodes: act as a
barrier to spread infection,
destroying or filtering out
bacteria before they can
pass into the blood.
• T-Cells: white blood cells
that regulate the action of
the immune system.
• B-Cells:cells that produce
antibodies.
Reducing the Risk of Disease
1. Immunity: the body’s natural defenses
against infection.
 Active immunity: resistance to disease
due to the production of antibodies.
 Passive immunity: the results from
introducing antibodies into the
bloodstream.
2. Vaccine: dead or weakened pathogens that
are given to the body to give a person more
immunity.
3. Other Healthy Lifestyle Behaviors: