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Study Guide Answers

1.     The immune system is the body's defense against what?
     dangerous organisms
2.     What are organisms that cause disease in other organisms called?
     pathogens
3.     What is the name for the body's healthy balance?
     homeostasis
4.     What are some common pathogens, and how do humans come into contact with them?
     Common pathogens are: bacteria, fungi, viruses, protozoans, and parasites. Pathogens can be transferred to people by contact with soil, contaminated water, and infected people or animals.
5.     What is any disease caused by a pathogen called?
     an infectious disease
6.     Are all diseases caused by pathogens?
     no
7.     What was Robert Koch trying to discover?
     the cause of anthrax
8.     Steps that directly relate a specific microorganism to a specific disease comprise what are known as "________________________________________________."
     Koch's Postulates
9.     Most human disease pathogens find the perfect place to survive and reproduce where?
     in the human body
10.     People cannot infect others during the "incubation period." True or false?
     false
11.     People can pass on a disease even before they show symptoms of a disease themselves. True or false?
     true
12.     Signs of a disease are commonly called "____________________________."
     symptoms
13.     What are two diseases that can be spread from animals to humans?
     rabies and the flu
14.     What are two non-living sources of disease?
     contaminated soil and contaminated water
15.     In what four ways can a pathogen be transmitted?
     by direct contact, by an object, through the air, or by a vector
16.     What's a "vector"?
     A vector is an intermediate organism that obtains the pathogen from one organism and carries it to another.
17.     Diseases that are passed from one person to another are called "_______________________________________________________."
     communicable diseases
18.     What served as the vector for the bubonic plague?
     fleas
19.     How do viruses spread?
     They invade cells and take over the host cells' metabolic and genetic machinery.
20.     How do bacteria inflict damage on cells?
     They release toxins.
21.     What's an "endemic disease"?
     One that is always present in an area.
22.     What kind of disease is the common cold?
     an endemic disease
23.     What is an "epidemic"?
     An epidemic occurs when many people in a given area are stricken by the same disease within a short period of time.
24.     What does an antibiotic do?
     It kills or inhibits the growth and reproduction of microorganisms.
25.     Antibiotics can treat what kinds of infections?
     bacterial infections
26.     What is the "lymphatic system"?
     It is a circulatory system that transports fluid to the bloodstream.
27.     What are the three basic functions of the lymphatic system?
     It keeps body fluids at a constant level, it absorbs fats from the digestive tract, it helps the body to defend itself against disease.
28.     The cells that make up the human body are constantly surrounded by what?
     tissue fluid
29.     When tissue fluid enters lymphatic vessels, what does it become known as?
     lymph
30.     On what does the immune system rely, to a great extent?
     white blood cells
31.     What are the most common white blood cells?
     lymphocytes
32.     What are "lymph nodes"?
     small masses of tissue that filter lymph
33.     What do tonsils do?
     They protect us from bacteria and other harmful materials that enter the nose and mouth.
34.     Where do lymphocytes mature and develop into cells that fight specific pathogens?
     in the thymus gland
35.     Your body's wide range of non-specific defenses make up its ________________________________.
     innate immune system
36.     What is often the body's first line of defense against a pathogen?
     the skin
37.     What is a body enzyme that can break down the cell walls of some bacteria?
     lysozyme
38.     Explain the process of phagocytosis.
     A white blood cell migrates to an infected area, surrounds a pathogen, and ingests it.
39.     What is "pus"?
     Pus is an accumulation of dead white blood cells and body fluids
40.     What characterizes inflammation?
     redness, swelling, pain, and heat
41.     What is "complement"?
     Complement is a group of proteins found in the blood. They attach themselve to the surfaces of pathogens.
42.     What is the building up of defenses against pathogens called?
     immunity
43.     What does an antigen do?
     It stimulates the production of antibodies.
44.     What are vaccines made of?
     weakened or dead pathogens
45.     Why is it important for us to wash our hands often?
     It's an easy way to prevent many infections.
© Educational Video Network, Inc. 2005 - www.evndirect.com
Your leading source for curriculum-based educational videos and DVDs.