Download Chp. 21 Understanding Infectious Diseases, Lesson 1 List 5 ways

Name ___________________________________ Class _________________ Date ___________
Chp. 21 Understanding Infectious Diseases, Lesson 1
(pp. 548–551)
Objectives
• Identify the causes of infectious diseases.
• Describe four ways in which infectious diseases are spread.
Infectious diseases (in FEK shus) are caused by organisms or viruses that enter and multiply within
the human body. Most are so small that they can be seen only through a microscope. Organisms this
small are called microorganisms (my kroh AWR guh niz umz). Microorganisms and viruses that
cause disease are called pathogens (PATH uh junz). Pathogens can cause an infectious disease
when they enter your body and multiply.
There are many kinds of pathogens. Bacteria (bac TEER ee uh) are simple, single-celled
microorganisms. Some bacteria injure cells by giving off poisons called toxins (TAHK sinz). Viruses,
the smallest pathogens, can multiply only after entering living cells. Fungi (FUN jy), such as yeasts,
molds, and mushrooms, grow best in warm, dark, moist areas. Protozoans (proh tuh ZOH unz),
singlecelled organisms that are much larger and more complex than bacteria, cause diseases such as
malaria. Other pathogens include mites, lice, and certain worms.
Pathogens can spread through contact with an infected person; an infected animal;
contaminated objects; or contaminated food, soil, or water.
• Infected people can spread diseases either through direct physical contact, such as shaking hands,
or through indirect contact, such as sneezing.
• Infected animals can transmit disease by biting a person.
• Pathogens that can survive for a period outside the body can spread through contaminated objects
such as eating utensils or doorknobs.
• Food, soil, or water can spread pathogens that were either present naturally or introduced by
infected people.
The pathogens can then enter the body through breaks in the skin or through the moist linings of
the eyes, ears, or other openings.
List 5 ways can you protect yourself from getting sick?
1.
2.
3.
4.
5.
Name __________________________________ Class _________________ Date ___________
Section 21-1
Note Taking Guide
Understanding Infectious Diseases (pp. 548–551)
Causes of Infectious Diseases
1. Complete the table with details about the different kinds of pathogens.
Pathogen
Bacteria
Description
Examples of Disease
a. ______________________
b. tetanus______________
______________________
c. ____________________
______________________
Viruses
d. ______________________
e. common cold________
______________________
f. ____________________
______________________
Fungi
g. ______________________
h. athlete’s foot_________
______________________
i. ____________________
______________________
Protozoans j. ______________________
k. malaria______________
______________________
l. ____________________
______________________
Name __________________________________ Class _________________ Date ___________
Section 21-1: Note Taking Guide (continued)
How Pathogens Are Spread
2. Complete the concept map about how pathogens are spread.