Communicable Diseases Chapter 24

Communicable Diseases  A disease spread from one living thing to another or through the environment.  Causes of diseases? Pathogens Pathogens An organism that causes disease.An organism that causes disease. They are EVERYWHEREThey are EVERYWHERE A disease will develop if your body can not fight off the infectionA disease will develop if your body can not fight off the infection

 Infection: Condition that occurs when pathogens enter the body, multiply and damage body cells.  Viruses: pieces of genetic material surrounded by a protein coat.  Bacteria: Single-celled organism-live anywhere on earth.

Viruses

Bacteria

Fungi  Plant-like organisms  Mold and yeast

Protozoans  Single celled organism

Rickettsias  Pathogens that resemble bacteria  Enter through insect bites

Three ways communicable diseases are transmitted? 1. Direct contact: 2. Indirect contact 3. Airborne A toxin is a substance that kills cells or interferes with their functions.

Vector  Organisms usually an arthropod, such as tick, that carries and transmits pathogens to humans or other animals.

Ways to make sure food is handled properly to avoid food borne illnesses  Wash hands before handling  Use paper towels to keep surfaces clean  Separate raw meat from other foods  Cook food to proper temperature  Chill leftover foods properly and quickly

In a 24 hour period, your body is exposed to millions of pathogens. Most of the time it stays free of infection because of…..

Lesson 2 Respiratory Infections  Many diseases begin as respiratory infections.  Respiratory tract: the passageway that makes breathing possible.

Common Cold  Mucous membrane

Influenza

Pneumonia

Strep Throat

Tuberculosis

Mononucleosis

Measles

Encephalitis

Meningitis

Chicken Pox

Lesson 3 Immune System  A network of cells, tissues, organs, and chemicals that fight off pathogens

Inflammatory response  Reaction to tissue damage  Area around injury becomes hot, swollen, red, and painful  Phagocytes: white blood cells that attack invading pathogens

Antigen  Substances found on the surfaces of pathogens  Immunity: the state of being protected against a particular disease.  Lymphocytes: a specialized white blood cell that coordinates and performs many functions of specific immunity

Antibody  Produced by lymphocytes and act against specific antigens

Active Immunity  Your body produces its own antibodies  May last a lifetime  Vaccines: Preparation of dead or weakened pathogens that are introduced into the body to stimulate an immune response

Passive immunity  You receive antibodies that are produced by another person or animal.  Short lived

Vaccinations Live-Virus Vaccines Pathogens grown under special laboratory conditions. Weakened stimulates production of antibodies (measles, mumps, rubella, chicken pox) Killed-Virus Vaccines  Inactivated pathogens, dead but still stimulates an immune response and antibodies production Flu, hep A, rabies, cholera, plague

Vaccinations Cont Toxoids Inactivated toxins from pathogens Tetanus and diptheria New and second generation vaccines Developed by scientists Hep B