The document outlines how infections occur, covering the role of various pathogens, including bacteria, viruses, fungi, and protozoans, in causing diseases. It emphasizes the importance of understanding sterile techniques, body defenses against infections, and differences in pathogen types, as well as the significance of vaccination. Additionally, it provides a detailed description of body defenses such as mucous membranes, fever, and immune responses that help to combat infections.

1. How Does Infection Occur?

2. CA Standards Know and understand medical terminology to interpret, transcribe, and communicate information and observations necessary for workers in the health care industry. (Health Sciences and Medical Technology Standard 2.5) Understand the importance and requirements of using sterile techniques in a laboratory. (Health Sciences and Medical Technology Standard A4.4) Students know the role of the skin in providing nonspecific defenses against infection. (Science Grades 9-12, Biology/Life Sciences Standard 10a) Students know the role of antibodies in the body’s response to in fection. (Science Grades 9-12, Biology/Life Sciences Standard 10b) Students know how vaccination protects an individual from infectious diseases. (Science Grades 9-12, Biology/Life Sciences Standard 10c) 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. (Science Grades 9-12, Biology/Life Sciences Standard 10d) Students determine the domain of independent variables and the range of dependent variables defined by a graph, a set of ordered pairs, or a symbolic expression. (Algebra I Standard 17.0)

3. Learning Objectives Students will: Observe and compare microorganisms found on fomites Identify different types of pathogens, types of diseases, and types of body defenses Simulate the spread of an infection throughout a population Determine factors that affect the rate of spread of a disease

4. How Does Infection Occur? Microorganisms are small, living organisms not visible to the naked eye. Pathogens are microorganisms that cause disease.

5. A DISEASE results if the invading pathogen causes the host to get sick.

6. Types of Pathogens There are different types of pathogens – they include: FUNGI BACTERIA VIRUSES PROTOZOANS PRIONS

7. Bacteria

8. Bacteria Single-celled organisms Live in a variety of environments Only 1% cause disease Usually killed by antibiotics Examples of diseases caused by bacteria include pneumonias, strep throat, tuberculosis

9. Viruses

10. Viruses Smallest of pathogens Nonliving Can only reproduce by invading a host cell NOT cured by antibiotics Examples of diseases caused by viruses include chicken pox, colds, influenza, small pox, HIV

11. Types of Disease Endogenous = the disease begins WITHIN the body Examples: Metabolic disorders Birth defects Tumors

12. Types of Disease Exogenous = the disease begins OUTSIDE the body Examples: Pathogenic organisms Radiation Chemicals Trauma Electric shock Temperature extremes

13. Types of Disease Nosocomial = diseases acquired by an individual in a health care facility Usually present in the facility and transmitted by health care workers to the patient

14. Types of Disease Opportunistic = disease that occurs when the body’s defenses are weak

15. Common Body Defenses Mucous membrane: lines the respiratory, digestive, and reproductive tracts; traps microorganisms to prevent them from invading

16. Common Body Defenses Cilia: tiny hairlike structures that line the respiratory tract to move pathogens out of the body

17. Common Body Defenses Coughing and sneezing removes microorganisms from the respiratory tract.

18. Common Body Defenses Hydrochloric acid: destroys pathogens in the stomach

19. Common Body Defenses Tears in the eye: contain chemicals that kill bacteria

20. Common Body Defenses Fever: kills pathogens by heat

21. Common Body Defenses Immune response: body produces white blood cells and antibodies to fight pathogens