What we will learn today . . .
1. Infectious diseases are spread by pathogens,
whether a virus or bacteria
2. Communicable diseases are contagious and
can spread rapidly from a single source
3. Nonspecific immune defenses are the body’s
first way to fight off general pathogens;
these defenses include the skin, mucus
membranes, stomach acid, and the
inflammatory response
The Immune System
We are constantly exposed to
pathogens!
Our body’s first line of defense against
those pathogens are nonspecific
defenses.
Nonspecific Defenses
Skin and Mucous Membranes
1. Skin is made of tough keratin
2. Skin releases sweat, oil, and waxes
which contain toxins
3. Mucus traps pathogens because it is
sticky
4. Stomach acids are lethal to most
bacteria
The Inflammatory Response
1. If pathogens enter the skin or mucous
membranes, this response occurs
2. Damaged cells release histamines, which
increase blood flow to the injured area
3. Inflammation results: redness, swelling,
warmth, and pain
4. Platelets will seal off any bleeding
5. White blood cells called macrophages
produce pus
The Inflammatory Response
Interferon
• Protein that inhibits the growth of
viruses
Fever
• Elevation of body temperature to kill
pathogens
References
• http://fig.cox.miami.edu/~lfarmer/BIL265/B
IL2001/immuniflame.JPG
• http://www2.bc.cc.ca.us/bio16/images/1501_Defense_1.jpg
• http://uhaweb.hartford.edu/bugl/images/imm
body.jpg
• http://farm3.static.flickr.com/2296/1888714
439_5276906b78.jpg
• http://www.mcmua.com/images/BoyWithFeve
r.jpg