the immune system packet #22 chapter #31. introduction the immune system includes all of the...
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The Immune SystemPacket #22
Chapter #31
Introduction
The immune system includes all of the structures and processes that provide a defense against potential pathogens (disease causing agents).
Immunity, the ability of an organism to resist disease, are in two forms Passive Immunity
Immunity passed from mother to child
Via genes There is no immune response
Active Immunity The body produces a response to
a particular pathogen.
Active ImmunityHuman Body Defense Mechanisms
Human Body Defense Systems
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Defense Mechanisms Non-Specific
Defense is a rapid response to a wide range of pathogens
Specific Takes several days to mount Delivered by the Immune
System Lymphocytes
Lymphocytes
Introduction
Lymphocytes (a type of white blood cell) are derived from unspecialized stem cells in the bone marrow.
Large numbers of lymphocytes are found in the thymus, spleen and lymph nodes.
There are two types of lymphocytes T cells
Thymus-dependent lymphocytes
B cells Derived from the discovery of B
cells in the bursa of Fabricius Mammals do not have this
organ
B Cells
Secrete antibodies (proteins) into the blood and lymph in order to inactivate pathogens.
Combat bacterial infections and some viral infections Because blood and lymph
are body fluids (humors), and since they release antibodies, the B cells are said to provide humeral immunity (antibody-mediated immunity)
T Cells
Attack host cells that have become infected with viruses or fungi, transplanted human cells and/or cancerous cells.
These cells do not secrete antibodies.
Must be in close proximity to destroy the infected cell.
Provide cell-mediated immunity. Cell-mediated immunity
involves the use of T cells.
Humoral Immuntiy vs. Cell-Mediated Immunity
See Pages 764 & 765 in textbook.
Specific Mechanisms
Specific Defense Mechanisms
Antigens Molecules (proteins), found on
the surface of cells, that stimulate the production of specific antibodies. The ID card. Natural Foreign
Haptens Small organic molecules that
can become antigens if they are bond to proteins.
Immunoassays*
Non-Specific Mechanisms/Barriers
Non-Specific Defense Mechanisms
Phagocytosis Engulfing of pathogens
Neutrophils Macrophages Phagocytes
Fever Produced by cytokines High fevers are dangerous
however fevers aid in the destruction of pathogens
Interferons Polypeptides that act as
messengers that protect other cells in the vicinity from viral infection.
The non-specific defense systems utilizes different “defensive lines” in order to be successful. {*Similar to having an alarm system for the house but
there are specific sensors, at the doors and windows for example, that trigger the alarm system.}
Introduction
The Immune SystemNon-Specific Defense System
Barriers/MechanismsThe First Line of Defense
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The Skin Mucous Membranes Cilia
Lines the lungs
Gastric Juice In the stomach Kills most microbes
The Immune SystemNon-Specific Defense Barriers/Mechanisms
The Second Line of Defense
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Second Line of Defense Inflammatory Response
Redness; swelling; heat; pain
Lymphocytes are activated.
Fever is developed.
The Immune SystemNon-Specific Barriers/Mechanisms
The Third Line of Defense
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Third Line of Defense Consists of mechanisms
and agents that target specific antigens Via the use of
lymphocytes.
Over Active Immune System
Allergies
An allergy is an oversensitivity to a normally harmless antigen.
Harmless antigens, that cause the over-the-top response, are known as allergens. Food
Peanuts Airborne
Pollen Pet dander Mold
Chemical Penicillin Jewelry metals
Review