Immunity

The Immune System is a defense system to help an organism survive against invaders. Organisms with a developed immune system are considered well adapted and more likely to survive (remember adaptation and evolution????)

Antibodies vs Antigens Foreign molecules are antigens. Brought in by pathogens (invaders such as bacteria or viruses) OR Brought in by harmless things such as dust, pollen or peanut butter! Our natural defense molecules are antibodies.

Immunity Cells Non-specific Response: Immune system reacts to a general invader: fever, itching, excess mucous. Macrophages (announce)- Engulf invaders and present antigens T Cells (attack)-also called dendritic cells Helper Killer Specific Response: Immune system reacts to a specific invader. B Cells (chemical warfare)- produce antibodies Memory Cells (later protection)-allow the immune system to fight subsequent infections faster.

Antibiotics are medications that help the immune system Antibiotics are medications that help the immune system. They can ONLY be used on living invaders such as bacteria. Viruses are NOT alive so antibiotics will not treat them! Vaccines- strengthen your immune system by making is work earlier.

Ways to build immunity… Active Immunity-your body works to build an immunity. YOU build antibodies Examples Natural: Illness or exposure to a pathogen Artificial: Vaccinations

Ways to build immunity… Passive Immunity-your body does not work to build an immunity, the antibodies are given to you. Examples Natural: From your Mother’s immune system via placenta or milk.

In autoimmune diseases, white blood cells attack the body’s healthy cells. Allergies are due to an overactive immune system. HIV destroys the T cells so the immune system cannot function.

There are over 60 autoimmune diseases.

Viruses are non living things. Viruses cannot grow, maintain homeostasis, process energy or reproduce without a host cell. Composed of a protein coat and a nucleic acid. (RNA or DNA). capsid DNA tail sheath tail fiber colored SEM; magnifications: large photo 25,000; inset 38,000x

Two ways viruses replicate: Lytic Cycle-invades a host cell, makes new viruses then destroys the cell by releasing the new viruses. Virulent. Ex. Flu Lysogenic Cycle- invades the host cell, integrates its DNA into the host DNA, begins to replicate with the host cell. Temperate. Certain chemicals, etc. can cause the viral DNA to move into the lytic cycle. Ex. Herpes

Treatment and Prevention Viruses are difficult to cure. Some anti-viral drugs will keep the virus in a dormant (lysogenic) stage but it is still there. Ex. Herpes, HIV Some viruses your body can fight. Ex. Common Cold, Flu Vaccinations Chemicals that stimulate the body’s immune system to produce antibodies. If your immune system is prepared to fight a disease you will not become symptomatic.

Bacteria Simple, single-celled, PROKARYOTIC organisms. Can be harmful and helpful. There are two groups of bacteria. Archaebacteria-old, extreme bacteria Eubacteria-newer, disease causing Named based on their cell shape.

Bacterial Reproduction Cellular Division (asexual) Since bacteria are only single celled organisms so they copy their DNA and split into two organisms. Conjugation (sexual) Two living bacteria bind together and one bacterium transfers genetic information (DNA) to the other. Q. Why might this be a problem? A. Bacteria that are resistant to antibiotics can share/exchange those genes!

How do bacteria become resistant to antibiotics?

MRSA

Treatment: Antibiotics kill living invaders inside the body. Prevention: Vaccines build up your immunity to a bacterial infection. So YOU can fight it. Treatment: Antibiotics kill living invaders inside the body. target one specific bacterium, fungus or protist not effective against viruses

Different pathogen cause common infectious diseases.

Diversity Booklet Due Date: 5/4 @ beginning of class 40 min. today 40 min. tomorrow 40 min. Friday Articles and materials are in the back.