Immune System and
Disease
CHAPTER 35
35.1
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Infectious disease can be caused by viruses, fungi,
bacteria, protists, and parasites.
Some diseases are spread through coughing or
physical contact with another person.
Some diseases are spread through contaminated
water or food or infected animals.
35.1 Continued
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Infectious diseases: occur when microorganisms
cause physiological changes that disrupt normal
body functions.
Germ theory of disease: microorganisms that were
commonly called germs.
Koch’s postulates: rules that led Koch to develop
rules for identifying microorganisms that cause a
specific disease.
Zoonosis: any disease that can be transmitted from
animal to human.
Vectors: carriers that transport pathogens.
35.2- Defenses Against Infection
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The immune systems specific defenses distinguish
between self and other, and they inactivate or kill
foreign substances or cells that enter the body.
The specific immune response has two main styles of
action- humoral and cell mediated immunity.
Nonspecific defenses include the skin, tears,
inflammatory response, interferon's, and fever.
35.2 Continued
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Inflammatory response: causes infected areas to become red and painful,
or inflamed
Histamines: increase the flow of blood and fluids to the affected area.
Interferons: interfere with viral growth.
Fever: increased body temperature that occurs in response to infection.
Immune response: specific recognition, response, and memory.
Antigen: any foreign substance that can stimulate an immune response.
Antibodies: to tag antigens for destruction by immune cells.
Humoral immunity: depends on the action of antibodies that circulate in the
blood and lymph.
Cell mediated immunity: depends on the action of macrophages and
several types of T cells.
35.3- Fighting Infectious Disease
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Vaccination stimulates the immune system with an
antigen.
Antibodies produced against a pathogen by other
individuals can be used to produce temporary immunity.
Antibodies can kill bacteria and some antiviral
medications can slow down the viral activity.
The immune system produces memory B cells and
memory T cells that speed up and strengthen the body's
response to a repeated infection or disease.
Two major reasons for the emergence of new disease
are the ongoing merging of human and animal habitats
and the increase in the exotic animal trade.
35.3 Continued
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Vaccination: injection of a weakened, or a similar
but less dangerous, pathogen to produce immunity.
Active Immunity: immunity that develops as a result
of natural or deliberate exposure to an antigen.
Passive Immunity: temporary immunity that develops
as a result of natural or deliberate exposure to an
antibody.
35.4- Immune System Disorders
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A strong immune response to harmless antigens can
produce allergies and asthma.
When the immune system attacks the body’s own
cells it produces an autoimmune disease.
35.4 Continued
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Allergy: trigger an inflammatory response causing
mast cells to release histamines.
Asthma: is a chronic disease in which air passes
narrow, causing wheezing, coughing and difficulty
breathing.