Section 31-1 “Pathogens and illness”
State Standards 10. Organisms have a variety of mechanisms to combat disease. As a basis for under-standing the human immune response: C. Students know there are important differences between bacteria and viruses with respect to their requirements for growth and replication, the body's primary defenses against bacterial and viral infections, and effective treatments of these infections.
KEY CONCEPT: Germs cause many diseases in humans
The Germ theory says that microorganisms cause diseases proposed by Louis Pasteur led to rapid advances in understanding disease
Koch’s postulates support the theory Disease-causing agents are called pathogens
What does the root word “path” mean? Feeling or suffering Examples: sympathy, apathy, empathy, telepathy, pathology Pathology is the study of diseases (sicknesses) Pathogen is anything causing disease
There are different types of pathogens. Bacteria are single-celled organisms cause illness by destroying cells release toxic chemicals Example: staph, strep throat
Viruses are genetic material (DNA) surrounded by a protein coat force host cells to make more viruses very small Example: flu, rhinovirus (rhin= nose; common cold), HIV
Fungi can be multicellular or single-celled take nutrients from host cells occur in warm and damp places Example: athlete’s foot, yeast infections
Protozoa are single-celled organisms use host cells to complete their life cycles take nutrients from host cell Example: malaria
Parasites are multicellular organisms grow and feed on a host possibly kill the host Example: tapeworm
Different pathogen cause common infectious diseases.
Pathogens can enter the body in different ways Pathogens can be transferred by direct or indirect contact Indirect contact does not require touching an infected individual touching an infected surface breathing in infected air
Vectors carry a pathogen and transmit it into healthy cells Direct contact requires touching an infected individual Includes: kissing sexual intercourse hand shaking tick