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Xiomara Sanchez Period 3 Lymphatic/Immune System - Coggle Diagram
Xiomara Sanchez Period 3 Lymphatic/Immune System
Location of Lymphatic organs and their functions
Lymph nodes
Lymph nodes are located in groups or chains along lymphatic vessels
The lymph nodes generally occur in chains along the parts of the
larger lymphatic vessels
Lymph nodes are not found in the central nervous system
Major areas of concentrations of lymph nodes: cervical, thoracic,
axillary, supratrochlear, abdominal, pelvic, and inguinal regions
Thymus
Shrinks in size during the lifetime; large in children, small in
adults, replaced by adipose & connective tissue in the elderly
Lobules contain lymphocytes, some of which mature into T cells
or T lymphocytes, that leave the thymus to provide immunity
Located in the chest, between the lungs and behind the breastbone or sternum
Spleen
Lies in the upper left abdominal cavity
Largest lymphatic organ in body
Similar to a large lymph node, except it contains blood instead
of lymph
Filters the blood and removes damaged blood cells and bacteria
Major functions of the Lymphatic & Immune systems
Lymphatic System
A second circulatory system
Lymphatic vessels collect and carry away excess tissue fluid
from interstitial spaces, eventually returning it to the blood
Lymph nodes, which are situated along lymphatic vessels,
contain lymphocytes, which help defend body against disease
Immune System
complex network of organs, cells and proteins that defends the body against infection, whilst protecting the body's own cells
keeps a record of every germ (microbe) it has ever defeated so it can recognise and destroy the microbe quickly if it enters the body again.
to fight disease-causing changes in the body, such as cancer cells.
Purpose and examples of First, Second and Third line of defense
First line of defense
Mechanical Barriers (skin & mucous membranes)
Prevent the entry of certain pathogens by providing a physical
separation of pathogens and internal tissues
Examples: unbroken skin and mucous membranes of the body
Includes hair, mucus, and sweat
Mechanical barriers represent the body’s first line of defense
The rest of the innate defenses are part of the second line of
defense
Second line of defense
Inflammation
A tissue response to injury or infection
Function of inflammation is to stop the spread of pathogens
and infection
Characterized by redness, swelling, heat, and pain
Major events of the inflammatory response include: Dilation of blood vessels, to increase of blood volume (causes redness), Increased capillary permeability, which leads to edema and heat, Attraction of white blood cells into the affected area, for phagocytosis
Chemical Barriers
Chemicals that kill many pathogens
Acidic environment provided by HCl in gastric juice is lethal to
some pathogens
Enzymes, such as pepsin in the stomach and lysozyme in tears,
destroy many pathogens
Interferons, hormone-like peptides secreted by lymphocytes
and fibroblasts when viruses or tumor cells are present, block
viral replication and slow tumor growth
Natural killer (NK) cells
Small group of lymphocytes, other than T cells and B cells
NK cells also secrete substances that enhance inflammation
Defend the body against viruses and cancer cells by secreting
cytolytic substances called perforins which lyse (break apart)
cell membranes of pathogens
Phagocytosis
Engulfment and digestion of pathogens, foreign particles, and
debris
Phagocytes are attracted to the injured area by chemotaxis, in
which they are attracted by chemicals from injured cells
Monocytes give rise to macrophages outside the blood, which are either free or become fixed in various tissues
Fever
Fever provides a hostile environment for pathogens that
reproduce best under normal human conditions
Phagocytic cells attack with greater vigor when the temperature
rises
Elevated body temperature causes the liver and spleen to take
up iron, reducing the amount in the blood, and keeping it from
fungi or bacteria, which need it for growth and metabolism
Third line of defense
Cellular immune response
response through cell-to-cell contact, as activated T cells interact directly with antigen-bearing cells
T cells also synthesize and secrete cytokines (such as interleukins and colony stimulating factors) that enhance cellular responses to antigens
Humoral immune response
Antibodies travel through the body fluids to attack and destroy antigens
Humoral immunity is the process of adaptive immunity manifested by the production of antibodies by B lymphocytes.
Develops in bone marrow
Antigens and antibodies
Antigens
Can be any large molecules that that can trigger an immune
response (ex: proteins, food, chemicals, etc...)
Before birth, the body makes an inventory of “self” antigens
Immune response is directed against “nonself” molecules,
which are usually large and complex foreign molecules
Antibodies
5 major types of antibodies (immunoglobulins) constitute the gamma globulin fraction of the plasma (IgG, IgA, IgM, IgE, IgD)
3 methods by which antibodies react to antigens:
Direct attack by agglutination, precipitation, or neutralization of
antigens; these methods make antigens more susceptible to
phagocytosis
Activation of complement results in opsonization, chemotaxis,
inflammation, agglutination, neutralization, alteration, or lysis
of antigens or antigen-bearing cells
Inflammation: Stimulation of local inflammatory changes in the
area, that helps prevent the spread of the pathogens
Passive vs. Active immunity
Immunity can be acquired by natural events, such as getting a disease, or induced artificially, by an injection
Immunity can be active or passive:
Active immunity -is obtained through antigen exposure; an
immune response occurs in the person, in which antibodies and
memory B cells are produced; this is long-lasting immunity
Passive immunity -is obtained by receiving antibodies; since
there is no antigen contact and no immune response occurs, no
memory B cells are produced; this is short-term immunity
Humoral response & Cellular response
Humoral
Develops in bone marrow
Humoral immunity is the process of adaptive immunity manifested by the production of antibodies by B lymphocytes.
Antibodies travel through the body fluids to attack and destroy antigens
Cellular
response through cell-to-cell contact, as activated T cells interact directly with antigen-bearing cells
T cells also synthesize and secrete cytokines (such as interleukins and colony stimulating factors) that enhance cellular responses to antigens
Artificial vs. Naturally acquired immunity
Naturally
Naturally acquired active
immunity
Exposure to live pathogens
Stimulation of an immune response
with symptoms of a disease
Naturally acquired passive
immunity
Antibodies passed to fetus from pregnant
woman with active immunity or to newborn through colostrum or breast milk from a woman with active immunity
Short-term immunity for a newborn
without stimulating an immune response
Artificially
Artificially acquired active
immunity
Exposure to a vaccine containing
weakened or dead pathogens or their
components
Stimulation of an immune response
without the severe symptoms of a disease
Artificially acquired passive
immunity
Injection of antiserum or gamma globulins
Short-term immunity without stimulating an immune response
Cells involved in the immune system and their functions
B cells
Antigen-bearing agents enter tissues.
B cell encounters an antigen that fits its antigen receptors.
Either alone or more often in conjunction with helper T cells, the B cell is activated. The B cell proliferates, enlarging its clone.
Some of the newly formed B cells differentiate further to become plasma cells.
Plasma cells synthesize and secrete antibodies whose molecular structure is similar to the activated B cell’s antigen receptors.
T cells
Antigen-bearing agents enter tissues.
An accessory cell, such as a macrophage, phagocytizes the antigen-bearing agent, and the macrophage’s lysosomes digest the agent
Antigens from the digested antigen-bearing agents are displayed on the membrane of the accessory cell.
Helper T cell becomes activated when it encounters a displayed antigen that fits its antigen receptors
Activated helper T cell releases cytokines when it encounters a B cell that has previously combined with an identical antigen bearing agent.
Cytokines stimulate the B cell to proliferate, enlarging its clone.
Some of the newly formed B cells give rise to cells that differentiate into antibody-secreting plasma cells.
Disorders associated with the Immune system
Hypersensitivity reactions
Excessive immune responses to a normally harmless antigen, that may lead to tissue damage
Some can occur in almost anyone, while others require hereditary predisposition
Immediate-reaction hypersensitivity (allergy)
Allergy mediators cause mucus production, vasodilation, and bronchoconstriction,resulting in an inflammatory response
Allergy mediators sometimes flood the body, resulting in anaphylaxis, a severe form of immediate-reaction hypersensitivity, which can be life-threatening
Antibody-dependent cytotoxic reactions
Example: a transfusion reaction to mismatched blood
Delayed-reaction hypersensitivity
Results from repeated exposure of skin to certain substances
Autoimmune disorders
immune system manufactures antibodies called
autoantibodies, and cytotoxic T cells, against some of its own
antigens
Autoantibodies damage the body’s own tissues
Autoimmune disorders may result from viral infection, faulty T
cell development, or reaction to a nonself antigen that closely
resembles a self antigen
Example: In Type I (insulin-dependent) Diabetes mellitus, beta
cells of the pancreas, which produce insulin, are destroyed by
autoantibodies