HE ED110 Lecture Notes - Lecture 9: Cestoda, Allergen, Immunotherapy
21 Jun 2018
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Chapter 9
Learning Objectives
1. Describe the step-by-step process by which infectious diseases are transmitted
2. Identify the body’s physical and chemical barriers to infection
3. Explain how the immune system responds to an invading microorganism
4. Identify the major types of pathogens and describe the common diseases they cause
5. Discuss steps you can take to prevent infections and strengthen your immune system
The Chain of Infection
An infection is an invasion of the body by microorganisms
A pathogen is a microorganism that causes disease
Toxins are poisonous substances
A reservoir is a natural environment in which a pathogen typically lives
The Chain of Infection
Vectors are insects, rodents, or other organisms that carry and transmit a pathogen
from one host to another
A systemic infection is an invasion by a microorganism that spreads through the blood
or lymphatic system to large portions of the body
The Body’s Defense System
The immune system is the body’s collective physical and chemical defenses against
foreign organisms and pathogens
Physical and Chemical Barriers
Skin
Mucous membranes
Cilia
The Immune System
Immunological defenders (neutrophils, macrophages, natural killer cells, dendritic cells,
lymphocytes)
Lymphocytes
T cells (arises bone marrow, matures in thymus)
B cells (matures in bone marrow, produces antibodies)
Helper T cells (activate other T cells and may help B cells)
Killer T cells (kill body cells that have been invaded by foreign organisms and can
kill cells that have been turned cancerous)
The Immune System
Antibodies are specialized proteins produced by white blood cells that can recognize
and neutralize specific microbes
Autoimmune disease is a disease in which the immune system attacks the person’s own
body
Antigens are markers on the surface of a foreign substance that immune system cells
recognize as non-self and that trigger the immune response
The Lymphatic System
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The lymphatic system is network of vessels and organs, including the spleen, lymph
nodes, thymus, and tonsils
Histamine is a chemical responsible for the dilation and increased permeability of blood
vessels in allergic reactions
Immunity
Immunity refers to mechanisms that defend the body against infection; specific
defenses against specific pathogens
Acquired immunity is the body’s ability to mobilize the cellular memory of an attack by a
pathogen to throw off subsequent attacks; acquired through vaccination and the normal
immune response
Immunization
Immunization is the process of conferring immunity to a pathogen by administering a
vaccine
A vaccine is a preparation of killed or weakened microorganisms, inactivated toxins, or
components of microorganisms that is administered to stimulate an immune response;
a vaccine protects against future infection by the pathogen
Immunization
Types of vaccines
Made in a variety of ways
May confer active or passive immunity
Vaccine safety
Soreness at injection site
There is no research to suggest that vaccination leads to autism
Allergy:
The Body’s Defence System Gone Haywire
Allergies are a disorder caused by the body’s exaggerated response to foreign chemicals
and proteins
Allergies result from a hypersensitive and overactive immune system
Allergens are substances that trigger an allergic reaction
Most allergic reactions are due to the production of a special type of antibody known as
immunoglobulin (IgE)
Strategies to deal with allergies include avoidance, medication, and immunotherapy.
Allergens
Pollen
Animal dander
Dust mites and cockroaches
Moulds and mildew
Foods
Insect stings
Anaphylaxis
A severe systemic hypersensitive reaction to an allergen characterized by difficulty
breathing, low blood pressure, heart arrhythmia, seizure, and sometimes death
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find more resources at oneclass.com
Document Summary
Identify the body"s physical and chemical barriers to infection. Learning objectives: describe the step-by-step process by which infectious diseases are transmitted. 2: explain how the immune system responds to an invading microorganism. Identify the major types of pathogens and describe the common diseases they cause: discuss steps you can take to prevent infections and strengthen your immune system. An infection is an invasion of the body by microorganisms. A pathogen is a microorganism that causes disease. A reservoir is a natural environment in which a pathogen typically lives. Vectors are insects, rodents, or other organisms that carry and transmit a pathogen from one host to another. A systemic infection is an invasion by a microorganism that spreads through the blood or lymphatic system to large portions of the body. The immune system is the body"s collective physical and chemical defenses against foreign organisms and pathogens. Immunological defenders (neutrophils, macrophages, natural killer cells, dendritic cells, lymphocytes)
