What does the lymphatic system do?
Returned fluids that leaked from the vessels back to the blood system
What are the three parts that the lymphatic system consists of?
1. Network of lymphatic vessels
2. Lymph (fluid in the vessels)
3. Lymph organs and tissues (cleanse lymph: Lymph nodes)
The lymphatic system provides structural basis of what?
Immune system to protect against diseases
The lymph system houses what kinds of cells?
phagocytic cells and lymphocytes
What structures are included in the lymph system?
Spleen
Thymus
Tonsils
Lymph nodes
Other lymphoid tissues
What two ways does the immune system defenses work?
Specific and nonspecific
In this immune system defense, lymphocytes are the main drive, involves identification, attacking, and developing an immunity to a specific pathogen.
Specific
In this immune system defense, it blocks and defends against any pathogen and cannot distinguish one attack from another.
Nonspecific
This is a fluid similar to plasma but it doesn't have the plasma proteins.
Lymph
These carry lymph from peripheral tissues to the venous system.
Lymphatic vessels
What is the function of the lymphatic system regarding lymphocytes?
To maintain, produce, and distribute
Where are lymphocytes produced?
in lymphoid tissues
in lymphoid organs
in red bone marrow
Why are lymphocytes distributed through out the body?
to detect problems
to travel to the site of an injury or infection
This is the blockage of lymph drainage from a limb and causes severe swelling as well as interfering with the immune system function.
Lymphedema
Lymphocytes make up how much of the circulating leukocytes?
20-30%
Are most lymphocytes stored or circulating?
Stored
What are the three types of lymphocytes?
T cells
B cells
NK cells
Of the circulating lymphocytes, what kind is the most numerous?
T cells (80%)
What are the three main kinds of T cells?
Cytotoxic T cells
Helper T cells
Memory T cells
This kind of T cell attacks cells infected by viruses and produce cell-mediated immunity.
Cytotoxic T cells
This kind of T cell stimulates the function of T cells and B cells.
Helper T cell
This kind of T cell is formed in response to foreign substances and remain in the body to give immunity.
Memory T cells
What are the two less common types of T cells?
Inflammatory T cells
Suppressor/inducer T cells
B cells make up what percentage of circulating leukocytes?
10-15%
B cells differentiate or change into what kind of cells?
Plasma cells
Plasma cells produce and secrete what?
Antibodies (immunoglobulin proteins)
Define antigen.
Targets that identify any pathogen or foreign compound
The binding of a specific antibody to its specific target antigen initiates what?
antibody-mediated immunity
Give another name for Natural Killer (NK) cells.
Large granular lymphocytes
NK cells are responsible for _________ surveillance.
immunological
These cells (lymphocytes) attack foreign cells, virus-infected cells, and cancer cells.
Natural Killer (NK) Cells
Lymphocyte production is also known as what?
lymphopoiesis
In bone marrow, cells called _________ divide into two types of lymphoid stem cells.
Hemocytoblasts
These two types of lymphocytes migrate throughout the body to defend peripheral tissues and retain their ability to divide.
T and B cells
This is a connective tissue dominated by lymphocytes.
Lymphoid tissue
This is an areolar tissue with densely packaged lymphocytes and germinal center that contains dividing lymphocytes.
Lymphoid nodules
Where are lymphoid nodules distributed at?
Lymph nodes
spleen
respiratory tract (tonsils)
along digestive, urinary and reproductive tracts
This is lymphoid tissue associated with the digestive system.
Mucosa-Associated Lymphoid Tissue (MALT)
MALT is made up of what?
aggregated lymphoid nodules clustered deep into intestinal epithelial lining
This organ contains a mass of fused lymphoid nodules.
Appendix
List the 5 tonsils in the wall of the pharynx.
Left and right palatine tonsils
Pharyngeal tonsils (adenoid)
Two lingual tonsils
The lymphoid organs (lymph nodes, thymus, spleen) are separated from surrounding tissues by what?
a fibrous connective tissue capsule
Give the passage of lymph flow through a lymph node in a network of sinus.
Subscapular space
through outer cortex
through deep cortex
through the core
into hilum and efferent lymphatics
The subscapular space contains what two cells?
Macrophages
dendritic cells
The outer cortex of a lymph node contains what cells in the germinal centers?
B cells
The deep cortex of a lymph node is dominated by what kind of cell?
T cells
The core or medulla of the lymph node contains what kinds of cells?
B cells and plasma cells, organized into medullary cords
When lymph is filtered, what is removed?
Debris
pathogens
99% of antigens
What happens in the first step of immune response when an antigen is presented?
Extracted antigens are "presented" to lymphocytes or attached to dendritic cells to stimulate lymphocytes
What do the lymph nodes of the gut, trachea, lungs, and thoracic duct do?
Protect against pathogens in the digestive and respiratory systems.
Lymph nodes are actually what?
Glands
Why do lymph nodes swell up?
in response to inflammation
What is the term for chronic or excessive enlargement of the lymph nodes?
Lymphadenopathy
What can lymphadenopathy indicate?
infections, endocrine disorders, or cancer
The atrophy of the thymus gland after puberty has what effect on the immune system?
diminishes the effectiveness
Body defenses provide ________ to fight infection, illness, and disease.
resistance
What are the two categories of defense?
Innate (nonspecific) defenses
Adaptive (specific) defenses
This kind of defense always works the same way, against any type of invader, and is a nonspecific resistance.
Innate
This kind of defense protects against specific pathogens, depends on activities of the lymphocytes and is a specific resistance. It usually develops after exposure to environmental hazards.
Adaptive
Give examples of innate defense.
Surface barriers - skin, mucous membranes
Internal defenses - phagocytes, NK cells, inflammation, fever, antimicrobial proteins
Give examples of adaptive defenses.
Humoral immunity - B Cells
Cellular immunity - T cells
What are the seven major categories of innate defense?
1. Physical barriers
2. Phagocytes
3. Immunological surveillance
4. Interferons
5. Complement
6. Inflammatory response
7. Fever
Immunological surveillance constantly monitors normal tissues and is carried out by what cells?
NK cells
What are interferons?
Chemical messengers that trigger production of antiviral proteins in normal cells
Antiviral proteins don't kill viruses but rather do what?
Block replication in the cell
What is the complement system?
a circulating system of proteins that assists antibodies in destruction of pathogens
What is an inflammatory response?
Localized, tissue-level response that tends to limit spread of injury or infection.
A fever does what three things?
increases body metabolism
accelerates defenses
inhibits some viruses and bacteria
What are the nonspecific physical barriers of defense?
outer layer of skin
hair
epithelial layers of internal passageways
secretions that flush away materials - sweat glands, mucus, urine
secretions that kill/inhibits microorganisms - enzymes, antibodies, stomach acid
In what ways do activated macrophages respond to pathogens?
Engulf pathogen and destroy it with lysosomal enzymes
Destroy pathogen by releasing toxic chemicals into interstitial fluid
All macrophages have what two things in common?
Move through capillary walls (emigration)
Are attracted or repelled by chemicals in surrounding fluids (chemotaxis)
Phagocytosis begins when:
phagocytes attaches to target and surrounds it with a vesicle
Activated NK Cells do what 4 things?
1. ID and attach to abnormal cells (nonselective)
2. Golgi apparatus in NK cell forms perforin vesicles
3. Vesicles release proteins called perforins
4. Perforins lyse abnormal plasma membrane
(Also attack cancer cells and cells infected with viruses)
Cancer cells contain what?
tumor-specific antigens
What is the term for when a cancer cell is able to avoid NK cells?
Immunological escape
Cells infected with viruses present __________ ______ on plasma membranes.
abnormal proteins
The abnormal proteins on the infected cells allow the NK cells to do what?
Identify and destroy them
These are proteins (cytokines) released by activated lymphocytes and macrophages.
Interferons
These are chemical messengers released by tissue cells to coordinate local activities and to act as hormones to affect the whole body.
Cytokines
Complements work together in __________.
Cascades
What are the two pathways that activate the complement system?
1. Classical pathways
2. Alternative pathways
How does the classical pathway of complement activation work?
Classical is the fast way
1.C1 binds to - antibody molecule attached to antigen
2. Bound to protein, acts as enzyme - catalyzes chain reaction
How does the alternative pathway of complement activation work?
Alternative activation is the slow way
Exposed to antigen
Factor P, B, D
Interact in plasma
Both the alternative and classical pathways of complement end with what?
Conversion of inactive complement protein C3 to active form C3b
What are the effects of complement activation?
Pore formation - Destruction of target plasma membranes
Enhancement of phagocytosis by opsonization - complements working with antibodies (opsonins)
Histamine release - increases the degree of local inflammation and blood flow
What triggers inflammation?
any stimulus that kills cells or injures tissue
What are the cardinal signs and symptoms of inflammation?
Swelling
Redness
Heat
Pain
What are the products of inflammation?
Necrosis - local tissue destruction in area of injury
Pus - mixture of debris and necrotic tissue
Abscess - pus accumulated in an enclosed space
This is any material that causes the hypothalamus to raise the body temperature.
Pyrogens
This is a special pyrogen that is released by active macrophages.
Endogenous pyrogens or interleukin-1 (IL-1)
In specific defense the T cells do what?
Provide cell-mediated immunity
Defend against abnormal cells and pathogens inside cells
In specific defense the B cells do what?
Provide antibody-mediated immunity
Defend against antigens and pathogens in body fluids
What are the 4 forms of immunity?
Innate
Adaptive
Active
Passive
This form of immunity is present at birth.
Innate
This form of immunity is acquired after birth.
Adaptive
This form of immunity has antibodies that develop after exposure to antigens.
Active
This form of immunity has antibodies that are transferred from another source.
Passive
This kind of active immunity is acquired through environmental exposure to pathogens.
Naturally acquired Active immunity
This kind of active immunity is acquired through vaccines containing pathogens.
Artificially induced active immunity
This kind of passive immunity contains antibodies acquired from the mother.
Naturally acquired passive immunity
This kind of passive immunity is acquired by an injection of antibodies.
Artificially induced passive immunity
What are the 4 properties of immunity?
1. Specificity
2. Versatility
3. Memory
4. Tolerance
In this property of immunity, each T or B cell responds only to a specific antigen and ignores all others.
Specificity
In this property of immunity, the body produces many types of lymphocytes. Each fights a different type of antigen and active lymphocytes clone themselves to fight specific antigen.
Versatility
In this property of immunity, some active lymphocytes stay in circulation and provide immunity against new exposure.
Memory
In this property of immunity, the immune system ignores "normal" antigens.
Tolerance
There are two main divisions of in the immune response, those of the T cells and those of the B cells. what are they?
Cell-mediated immunity (T cells)
Antibody-mediated immunity (B cells)
What are the 4 major types of T cells?
1. Cytotoxic (T8) cells
2. Memory T cells
3. Helper T cells (T4)
4. Suppressor T cells
This kind of T cell attacks cells infected by viruses and is responsible for cell-mediated immunity.
Cytotoxic T cells
This kind of T cell clones themselves in response to "remembered" antigen.
Memory T cells
This kind of T cell stimulates the function of T cells and B cells.
Helper T cells
This kind of T cells inhibit function of T cells and B cells.
Suppressor T cells
T cells only recognize antigens that are bound to ______________ in plasma membranes.
glycoproteins
These are the membrane glycoproteins that bind to antigens and are genetically coded. They differ among individuals.
MCH Proteins
There are two classes of MHC Proteins, Class I and Class II. Which class is found in the membranes of all nucleated cells?
Class I
There are two classes of MHC Proteins, Class I and Class II. Which class is found in the membranes of antigen-presenting cells (APCs) and lymphocytes?
Class II
This class of proteins pick up small peptides in cells and carry them to the surface.
Class I MHC Proteins
Class I MHC Proteins: T cells ignore what?
Normal peptides
Abnormal peptides or viral proteins activate ___ _______ to destroy cells.
T cells
In Class II MHC Proteins, antigenic fragments come from what?
Antigenic processing of pathogens
Antigenic fragments bind to what?
Class II proteins
Antigenic fragments are inserted into plasma membranes to stimulate what?
T cells
Antigen-presenting cells are responsible for what?
Activating T cells against foreign cells and proteins
What are the three kinds of phagocytic APC's and where are they found?
1. Free and fixed - in connective tissue
2. Kupffer Cells - in the liver
3. Microglia - in the CNS
What are the two kinds of non-phagocytic APCs and where are they found?
1. Langerhans - in the skin
2. Dendritic - lymph nodes and spleen
What cell does antigen recognition recognizes?
T cells
These are known as cluster of differentiation markers.
CD markers
CD markers are located where?
In T cell membranes
CD3 receptor complexs are found where?
in all T cells
What are two important CD markers?
1. CD8 - found on cytotoxic T cells and suppressor T cells
2. CD4 - found on helper T cells
CD8 and CD4 bind to what receptor complex?
CD3
For T cell to be activated, it must be costimulated. What does this mean?
Binding to stimulating cell at second site which confirms the first signal
What three steps does a cytotoxic T cell go through?
1. Release perforin
2. secrete poisonous lymphotoxin
3. Activate genes in target cell
This kind of T cell secretes suppression factors, inhibits responses of T and B cells, act after initial immune response, and limit immune reaction to a single stimulus.
Suppressor T cells
What are the 4 functious of Cytokines?
1. Stimulate T cell divisions
2. Attract and stimulate macrophages
3. Attract and stimulate activity of cytotoxic T cells
4. Promote activation of B cells
These cells are responsible for antibody-mediated immunity,and attack antigens by producing specific antibodies.
B cells
During B cell sensitization, the antigens are:
Taken into the B cell
Processed
Reappear on surface, bound to class II MHC protein
Sensitized B cells are prepared for activation but needs _____ ____ cell activated by the same antigen.
T cell
Activated B cell divides into:
Plasma cells
Memory B cells
These cells synthesize and secrete antibodies into interstitial fluid.
Plasma Cells
These cells, like memory T cells, remain in reserve to respond to the next infection.
Memory B cells
An antibody structure is made of two parallel pairs of polypeptide chains. what is the difference between the two chains?
One is heavy and one is light
An antibody structure is made of two parallel pairs of polypeptide chains. what is the similarity between the two chains?
each chain contains constant segments and variable segments
What are the 5 heavy-chain constant segments?
1. IgG
2. IgE
3. IgD
4. IgM
5. IgA
The variable segments of light and heavy chains determine __________ of antibody molecule.
Specificty
A complete antigen has two _________ _________ sites.
Antigenic determinate sites
These must attach to a carrier molecule to act as a complete antigen.
Hapten
What are the dangers of haptens?
antibodies produced will attack both hapten and carrier molecule
if carrier is "normal": antibody attacks normal cells
What are the seven functions of antigen-antibody complexes?
1. neutralization of antigen binding sites
2. precipitation and agglutination
3. activation of complement
4. attraction of phagocytes
5. opsonization increasing phagocyte efficiency
6. stimulation of inflammation
7. prevention of bacterial and viral adhesion
Primary and secondary responses to antigen exposure occur in both _____________ and ________ immunity.
cell-mediated
antibody-mediated
The first exposure to an antigen produces initial what?
primary response
The second exposure triggers what?
secondary response that is more extensive and prolonged and the memory cells are already primed
What are 4 characteristics of the primary response?
takes time to develop
antigens activated B cells
plasma cells differentiate
Antibody titer level slowly rises
Is the primary or secondary response the peak response?
Primary
How long will the primary response take to develop?
up to two weeks
What is produced faster that IgG but is less effective?
IgM
The secondary response activates what kind of cells?
Memory B cells
What are the effects of memory B cell activation on IgG?
rises very high and quickly
can remain elevated for extend time
What are the effects of memory B cell activation on IgM?
Production is also quicker
slightly extended
What is the combined response to bacterial infection?
1. Neutrophils and NK cells begin killing bacteria
2. Cytokines draw phagocytes to area
3. Antigen presentation activates: helper T cells, Cytotoxic T cells
4. B cells activate and differentiate
5. Plasma cells increase antibody levels
What is the difference in a viral response vs. a bacterial response?
Cytotoxic T cells and NK cells are activated by contact with the virus-infected cells
Before birth, what antibody passes to the fetus through the placenta?
IgG
A mothers milk provides what kind of antibodies?
IgA