Transcript Our Defense System Spring 2014

Our Defense System
Spring 2014
Two ways your body defends you
• Nonspecific – attacks invaders without
discretion. (doesn’t attack only specific
invaders)
• Specific – cells that are trained to only
attack one kind of invader (chicken pox, for
example).
Non Specific Defenses
First line of defense (4)
1. Skin
– Physical barrier as long as it’s
unbroken
– Chemical barrier – sweat
• acidic - inhibits bacterial growth
• contains lysozyme - an enzyme that
digests bacterial cell walls (also in
tears)
Non Specific Defenses
First line of defense
2.Hair –
Some are large, like
eyelashes or eyebrows
Most are very small,
called cilia, they line
the respiratory
system. They trap
and sweep particles
out
Nonspecific Defenses
First line of defense
• 3. Mucous
Membranes
– Layers of
cells that
produce
mucous.
– Trap
pathogens
Non specific Defenses
First line of defense
4. Stomach Acid
• Hydrochloric acid
(HCl)
• pH around 1 or 2
• Destroys most
pathogens you
swallow
• Stomach protects
itself with a thick
lining of mucous
Non specific Defenses
Second Line of defense (4)
1. Inflammatory
Response
2. Temperature
response
3. Proteins
4. White blood
cells
Inflammatory response – triggered
by pathogens enter the skin
• Injured cells release
histamine.
• Histamine causes local blood
vessels to dilate, increasing
blood flow in the area.
• But it also brings more white
blood cells which will
destroy the pathogens
• Increased blood flow causes
swelling, redness, raised
temperature.
Temperature Response
Normal body temperature is 37 degrees C
(98.6 degrees F)
As pathogens invade, the
body will increase
several degrees. This
will inhibit diseasecausing bacteria.
Proteins and White blood cells
• When a cell is attacked by a virus, the cell
releases a protein called interferon
• Interferon travels to other cells and prevents
the virus from successfully reproducing
• White blood cells travel throughout the body
and destroy and consume any non-self cell.
Specific Response
Certain white blood cells (T cells) are
programmed to recognize only a
particular pathogen (Called antigen)
You have thousands of different T cells.
They each recognize a different antigen.
When they recognize an antigen, they clone
themselves many times and will destroy
the antigen. Some stick around for years
and work as immunological memory
Primary and secondary response
• Let’s graph it!!
• Vaccines introduced a deadened form of a
pathogen. Your body makes the memory
cells
• Then when you are exposed to the real
thing, your body knows exactly how to fight
it.
• A vaccine is like a fire drill for your
immune system
What’s on the test
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Viruses vs. bacteria (venn diagram)
HIV/AIDS virus notes
Your defense system notes
Old material
The test is 5/20, 5/21