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 growthacidic - inhibits bacterial growth contains lysozyme - an enzyme that digests bacterial cell walls (also in tears)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 disease- causing 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 Viruses vs. bacteria (venn diagram) HIV/AIDS virus notes Your defense system notes Old material The test is 5/20, 5/21