Your Body’s Defense
Physical Defenses
 First line of defense
 Skin
 Hair
 Mucous
 Cilia
 Saliva
 Tears
 Sweat
 Digestive tract
Skin
 Protects from micro-organisms entering
the body
 Open cuts/ sores provide entrance
 Cells die and are shed
Sweat
 Our body has many sweat glands
 Sweat is released to control body temp
 Sweat contains acids that kill pathogens
Mucous Membranes
 Moist linings around all
entrances to body
 Covered with mucous
 Mucous = sticky
substance
 Mucous traps
pathogens
 Mucous is released
from body
Saliva & Tears
 Contain enzymes
that fight
pathogens
 Tears wash away
foreign
substances
Cilia
 Tiny hair-like structures
 Trap pathogens
 Help remove mucous from body
Digestive Tract
 Moves pathogens
out of body
 Acids/ chemicals in
digestive tract
 Mouth/Esophagus/
Stomach/ intestines
 Chemicals kill
pathogens
Second Line of Defense
 Occurs after pathogen enters the body
 Inflammation
Inflammation
 1st stage of healing
 Increased blood flow to area
 Increased size/ temperature/ redness
 Caused by dilation of blood vessels
Phagocytes
 Blood brings
phagocytes & chemicals
 Phagocytes = white
blood cells
 Digest pathogens,
dead cells, waste
 Chemicals
 Kill pathogens & start
tissue healing
Immune System
 Last line of defense
 Lymphatic system,
lymph nodes, lymph,
lymphocytes
 Lymph nodes store
and filter lymph
 Lymph - fluid
containing
lymphocytes
 Lymphocytes - white
blood cells
Lymphocytes
 B-cells & T-cells
 T-cells

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Produce interferon- warns
cells about pathogen
Kill some pathogens directly
 B-cells create antibodies

Antibodies bind to
pathogens/ toxins until
phagocytes find them
Immunity
 Active Immunity-body
creates antibodies

Through sickness of
immunization
 Immunization/ vaccine –
injected with small amount
of pathogen
 Passive Immunity-passed
from mother to child
through birth or breast milk
Treatment
 Antibiotics – kill living organisms

Treat bacterial infections only
 Fungus are treated with cream or topical
treatment
Treatment of Virus
 Anti-viral can stop a virus from
reproducing



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Most viruses are fought by our immune
system with…
Rest
Proper diet
Water
Prevention
 Eat well-balanced meals.
 Get enough rest. (8 hours)
 Get exercise. (30 minutes at least 3-4 x
week)
 Wash hands/ shower.
 Keep hands out of eyes and mouth.
 Have regular physicals/ dental visits.
Prevention
 Get vaccinated
 Don’t share utensils,
glasses, cups etc.
 Avoid sick people.
 Avoid stress. Use stress
management techniques.
 Find time to relax.
Questions