193 terms

A&P II - Lymphatic System

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What type of immunity is present at birth and has no memory?
Innate/nonspecific
What immunity recognizes specific antigens and has memory (also involves B and T lymphocytes?)
Adaptive/Specific
What makes up the lymphatic system?
Lymph, lymphatic vessels, red bone marrow, nodes, nodules, thymus, spleen
What makes up lymphatic tissue?
Specialized reticular connective tissue with many B and T lymphocytes
What is interstitial fluid that has entered lymphatic vessels called?
Lymph
What are the three main functions of the lymphatic system?
Drain excess interstitial fluid, transport dietary lipids and fat soluble vitamins, carry out immune functions (B cell and T cell)
Does lymph circulate?
No, it is a one way journey to venous blood
What moves lymph around the body?
Milking by skeletal muscles and respiratory pump
What is the pathway of lymph?
Lymphatic capillaries>lymphatic vessels>lymphatic trunks>Lymphatic ducts>Subclavian vein
What are blind tubules in most tissues?
Lymphatic capillaries
Where are there no lymphatic capillaries?
Avascular tissues, CNS, parts of spleen and red bone marrow
What lymphatic duct drains most of the body?
Thoracic duct
What are the lymphatic trunks of the body?
Lumbar, inestinal, broncomediastinal, subclavian, and jugular
What duct drains the upper right portion of the body?
Right lymphatic duct
What are specialized reticular connective tissue (loose CT)?
Lymphatic tissues
What is the term for functional fibers?
Parenchyma
What is the supporting framework called?
the Stroma
What are the extentions of the capsule into the body of an organ called?
Trebeculae
What is a characteristic of a lymphatic organ?
CT capsule
Why are lymphatic nodules not an organ?
They lack a CT capsule
What are two of the subdivisions of the lymphatic nodule?
Medulla and cortex
What is the depression in an organ where vessels enter/leave called?
Hilus or Hilum
What are the two divisions of lymphatic function?
Primary and Secondary
What is it called when something is capable of an immune reaction and able to recognize self antigens?
Immunocompetent
What are the primary lymphatic organs and tissues?
Red bone marrow and thymus
What are some secondary lymphatic organs and tissues?
Lymph nodes, spleen and lymphatic nodules
What type of lymphatic organ and/or tissue is where stem cells divide and become immunocompetent?
Primary
What type of lymphatic organ and/or tissue is where most immune reactions occur?
Secondary
Where does lymphatic tissue originate from?
Mesoderm
When is a human's thymus the largest?
In infancy
What is the thymus' role in the immune system?
It is responsible for supplying secondary lymphatic tissues with T cells
Where is the thymus' origins?
An outgrowth of the 3rd pharyngeal pouch/gill pouch
What cells make up the cortex of the thymus?
T cells, epithelial cells, dendric cells, macrophages
What do epithelial cells in the thymus do?
Make thymic hormones which cause T cells to mature
How many of the T cells undergo apoptosis and get phagocytized by macrophages?
98%
Where do the remaining surviving cells from the thymus go after the cortex?
Into the medulla
What cells make up the medulla of the thymus?
Mature T cells, epithelial cells, dendric cells and macrophages
What are parts of the thymus' medulla that contains degenrate epithelial cells with keratohyalin and keratin?
Thymic/Hassalls corpuscles
Where do T cells go after the thymus?
Carried by blood to colonize nodes and spleen
Where are most clusters of lymph nodes located?
Groin, axilla mammary glands
What makes up the inside of a lymph node?
Reticular fiber and fibroblasts
What is the parenchyme of the lymph node?
One outer cortex, one inner cortex and one medulla
Where are the efferent vessels located on a lymph node?
At the hilum
Which types of lymphatic tissue or organs filter lymph?
Secondary lymphatic tissue
Which type of lymphatic tissue or organ encounters antigens?
Secondary lymphatic tissues or organs
What is the largest mass of lymphatic tissue?
The spleen
What type of lymphatic tissue is the spleen?
Secondary lymphatic tissue
Does the spleen filter lymph?
No, only filters blood
Where do the afferent vessels arise in the spleen?
Within the spleen
What makes up the stroma of the spleen?
CT capsual, trabeculae, reticular fibers and fibroblasts
What is the parenchyme of the spleen?
White pulp and red pulp
What cells are in the white pulp?
B and T cells and macrophages
What is in the red pulp (venous sinuses)?
1) Fixed macrophages
2) Storage of platelets
3) Hemopoiesis during fetal life
Where do you find lymphatic nodules?
Scattered throughout the lamina propria (CT of mucosa), some also in the submucosa in GI, urinary, respiratory, and reproductive systems
What is another name for lymphatic nodules?
MALT - mucosa assosiated lymphatic tissue
What are some aggregations of lymphatic nodules in the body?
Tonsil, appendix, Peyers patches
What are the first lines of defense for the immune system?
Physical and chemical barriers
If and antigen penetrates the physical and chemical barriers what is the second line of defense?
Antimicrobial proteins (4), NK cells phagocytes, inflammation and fever
What are antimicrobial proteins made by fibroblasts, lymphocytes, and macrophages that have been infected by a virus? (interfere with viral replication)
Interferons (IFNs)
What are normally inactive antimicrobial proteins in plasma and cell membranes that enhance allergic, inflammation and immune rxns when activated?
Complement system
What are plasma proteins that bind to iron ions which prevent bacteria from using iron they require to grow?
Iron binding proteins
What are four iron binding proteins?
transferrins (cary iron in blood), ferritin (stores iron), lactoferrin (in milk, saliva, and mucus) and Hb in RBC
What are two examples of antimicrobial proteins (AMPs)?
Defensins (made by neutrophils, macrophages and epithelium) and thrombocidin (by platelets)
What are lymphocytes in the blood, spleen, nodes, and red bone marrow that are not B or T cells?
Natural killer cells
What do NK cells produce?
Perforins which cause lysis and apoptosis
What are two kinds of phagocytes?
Neutrophils and macrophages
What are the five stages in phagocytosis?
1. Chemotaxis
2. Adherence (opsonization)
3. Ingestion (pseudopods and phagosome)
4. Digestion (lysosomes fuse with phagosome)
5. Killing (oxidative burst - superoxide, hypochlorite and peroxide)
What are the three steps of inflammation?
1. Vasodilation and increased permeability
2. Emigration
3. Tissue repair
What occurs during vasodialtion in inflammation?
Clotting proteins leave b/c of increased permeability
What are the clotting proteins used during inflamation?
1. Histamine - from mast cells, basophils and platelets *MOST IMPORTANT VASODILATOR
2. Kinins - polypeptides formed in the blood (Bradykinin is an example)
3. Prostaglandins - from damaged cells, intensify 1 and 2
Also, leukotrienes and complement
What happens during emigration of phagocytic cells in inflammation?
First neutrophils, then they die off, then macrophages
What causes a fever?
Often because toxins from bacteria trigger macrophages to release interleukin 1 (resets thermostat in hypothalmus)
What are antigens?
Substances not recognized as "self" and cause an immune response
What is a complete antigen?
has 2 functional properties: immunogenicity and reactivity
What is the ability of an antigen to provoke an immune response called?
Immunogenicity
What is the ability of an antigen to react with those specific antibodies or immune cells that the immune rxn provoked?
Reactivity
What are the size of most antigens?
large complex molecules with a molecular weight of 10,000 daltons or more
Besides being proteins, what are four other things that antigens can be?
Nucleic acids, lipoproteins, glycoproteins, and polysaccharides
Are polymers with simple repeating units antigenic?
No
What are the small parts of an antigen that trigger an immune response?
Epitopes
Since epitopes have immunogenicity, what do they stimulate?
Production of Ab and T cells
What are molecules that are too small to trigger an immune response on their own?
Haptens
Do haptens have immunogenicity and reactivity?
They have reactivity but no immunogenicity
What are some examples of Haptens?
Poison ivy, penicillin, detergents, and some cosmetics
What are the two classes of MHC antigens?
MHC Class I and MHC Class II
Where are MHC Class I antigens found?
On cell membranes except for RBC
Where are MHC Class II antigens found?
only on antigen presenting cells (Macrophages, dendritic cells and B cells)
What are the APC's?
Macrophages, dendritic cells and B cells
What are displayed in the grooves of MHC antigens?
Peptides
What kind of peptides do MHC-I antigens from healthy body cells display?
Peptides from normal protein breakdown
What kind of peptides do MHC-I antigens from unhealthy body cells display?
abnormal proteins that are seen as foreign
What kind of peptides do MHC-II antigens display?
Peptides that come from outside the body (exogenous antigens)
How do immucompetent B cells arise?
Pluripotent stem cells in red bone marrow>develop in primary lymphatic tissues>make antigen receptors that recognize antigens>Fully mature in bone marrow (continues throughout life)
How do immucompetent Tcells arise?
Pluripotent stem cells in red bone marrow>develop in primary lymphatic tissues>make antigen receptors that recognize antigens>Go from the bone marrow to the thymus to complete maturation (most maturation occurs before puberty)
Besides an antigen receptor, what else do T cells have on their membrane?
CD4 and CD-8 receptors
What type of cell is responsible for antibody mediated immunity (also called Humoral immunity)?
B cells>plasma cells>secrete antibodies
What type of cell is responsible for cell mediated response/immunity?
T cells
CD-8 T cells>T cytotoxic
CD-4 T cells>T helper cells
What is antibody mediated immunity especially effective against?
Extracellular An, An in body fluids, extracellular pathogens that multiply in body fluids
What is cell mediated response/immunity especially effective against?
Intracellular pathogens CELLS ATTACKING CELLS
-Forign transplanted tissue
-Protist or helminth parasite
-Some cancer cells
Which cells directly bind antigens in lymph, interstitial fluid, plasma?
B cells
Which cells recognize fragments of foreign antigens that are presented along with self antigens?
T cells
Do B cells or T cells leave secondary lymphatic tissue to go the site of infection?
T cells only - B cells stay in secondary lymphatic tissue
What is the process by which a lymphocyte proliferates and differentiates?
Clonal selection
Where does clonal selection occur?
In secondary lymphatic tissues
What are the two types of cells that are created from clonal selection?
1. Effector cell (carry out immune rxn
2. Memory cell
What is the function of an effector cell?
carry out the immune reaction (usually destroys or inactivates a An)
What are some examples of effector cells?
Active T helper cells, Active T cytotoxic cells and Plasma cells
What is the function of memory cells?
To carry out subsequent responses to same An. WIll proliferate and differentiate rapidly
What are some examples of memory cells?
Memory T helper cells, Memory T cytotoxic cells and Memory B cells
How long do effector cells and memory cells usually live?
Effector cells die after immune rxn has ended and memory cells can last for decades
If An get in the blood where are they likely to end up?
Spleen
If An get in through the skin where are they likely to end up?
lymph vessels and nodes
If An get in the mucosae where are they likely to end up?
the MALT
What are the common portals of entry for An?
Respiratory and Digestive
How many types of epitopes can the immune system recognize and bind?
More than 10,000,000,000
How are B and T cells able to respond and recognize An before the An even enter the body?
Genetic recombination
What happens if a T cells comes across a peptide fragment from a foreign protein?
T cell will recognize th An-MHC as foreign and will begin an immune reaction
What type of foreign An must exist for a T cell to recognize it as foreign and begin an immune reaction?
An can be EITHER a MHC-1 with an abnormal body protein or it can also be a MHC-II with a protein from outside the body
What are foreign antigens in fluids outside body cells called?
Exogenous Antigen (bacteria, toxins, parasitic worms, dust, pollen, virus)
Which type of cell can directly bind antigens in the lymph, IF or plasma?
B cells
When do T cells recognize antigenic proteins?
When they have been processed and presented with a MHC An
Which type of T cell is involved with a exogenous antigen?
CD-4
Which type of T cell is invoved with a endogenous antigen?
CD-8
Is an APC necessary for an endogenous or exogenous antigen?
Only for Exogenous
What is a name for many small protein hormones made by many cells?
Cytokines
What cells make cytokines?
Lymphocytes
APCs
Fibroblasts
Endothelial cells
Monocytes
Hepatocytes
Kidney cells
What are the 7 types of cytokines?
1. Interleukin 1
2. Interleukin 2
3. Alpha and beta Interferons
4. Lymphotoxins
5. Perforin
6. Granzymes
7. Granulysin
What is the function of interleukin 1?
Causes fever, T helper cell proliferation
What is the fuction of interleukin 2?
Important for entire immune response. Costimulator of B, T; NK (only T helper cells make it)
What makes alpha and beta interferons?
Only a virus infected cell
What is the function of Lymphotoxin?
From T cytotoxic cells and NK cells, causes Lysis
What is the function of Granzymes?
From T cytotoxic cells and NK cells. Casues cell to undergo apoptosis
What is the function of Granulysin?
From T cytotoxic cells and causes holes to form in the microbial cells membrane
What are the two signals that a T cell requires to become activated?
1. Antigen recognition
2. Costimulation by Il 2 (or another cytokine)
What is the purpose of CD-4 and CD-8 receptors on T cells?
Maintain the protein/MHC complex
When T helper cells release Il 2 and it causes T helper cells to proliferate and make more, what kind of feedback system is it?
Positive
What else does Il 2 stimulate?
NK cells, B cells, T helper and T cytotoxic cells
What type of T cell is produced by a exogenous antigen, and what is the type of receptor?
T helper cells, CD-4
What type of T cell is produced by an endogenous antigen, and what is the type of receptor?
T cytotoxic cells, CD-8
Which type of cells leave secondary lymphatic tissues/organs to seek out and destroy the specific foreign cells?
T cytotoxic cells
What 5 things do T cytotoxic release to eliminate an invader?
1. Granzymes - induce apoptosis
2. Perforin - Makes a channel in cell membrane causing Lysis
3. Granulysin - Enters through channels created by perforin ausing lysis
4. Lymphotoxin - activates enzymes that destroy DNA
5. Gamma Interferon - Attracts phagocytic cells to area
Where do B cells encounter antigens?
In secondary lymphatic tissues (where they remain)
What do B cells produce when they differentiate?
Plasma cells and Memory B cells
Can B cells respond to unprocessed An in interstitial fluid and lymph?
Yes, but response is more intense if they process the An
Are B cells APC?
Yes
What is another name for a gamma globulin or Ab?
Immunoglobulins
What are the five classes of Immunoglobins?
IgG
IgM
IgA
IgD
IgE
What type and number of chains make up an Ab?
4 polypeptide chains (2 heavy and 2 light)
What holds the polypeptide chains together in an Ab?
Disulfide bonds
What are the two regions of an Ab?
Constant and a variable region
What does the constant region on an Ab detemine?
Determines the class
What is the purpose of the variable region on an Ab?
Binds to the Ab
What are some of the actions of an Ab?
1) Neutralize the antigen
2) Immobolize the bacteria
3) Agglutination/precipitation of An
4) Activate complement
5) Enhance phagocytosis
What does it mean when an Ab neutralizes an An?
Blocks the binding sites or neutralizes the toxins
What does it mean when an Ab causes the agglutination/precipitation of an An?
Makes the An become a clump or solid
What does it mean when an Ab activates a complement?
Chemotaxis of phagocytes, inflammation, opsonization and lysis
How does an Ab enhance phagocytosis?
Attracts phagocytic cells and enhances their activity
What is the most abundant class of Ab?
IgG
What Ab crosses the placenta?
IgG
What class of Ab is AntiRh?
IgG
What class of Ab decreases with stress?
IgA
What Ab is found in sweat, tears, saliva, mucus, breast milk, Gi secretions, lymph, blood and on Mucosae
IgA
What is the first class of Ab that plasma cells release?
IgM
What two classes of Ab are know to fix or activate a complement?
IgG and IgM
Which class of Ab when its a monomer it serves as An receptors on B cells?
IgM
What class of Ab are antiA and AntiB?
IgM
What class of Ab is mainly found on B cell surface as an antigen receptor?
IgD
What class of Ab is found on Mast cells and basophils?
IgE
What class of Ab is prevelent in allergic and hypersensitivitey reactions?
IgE
What type of defense is the complement system?
Nonspecific
What defense involves 30 proteins made by the liver that circulate in plasma and also are found in tissues?
Complement System
What are the three ways a complement system can become activated?
1. Classical pathway
2. Alternative pathway
3. Lectin Pathway
What type of pathway activates the complement system when an An-Ab complex is formed?
Classical pathway
What type of pathway activates the complement system that involves lipid-carbohydrate complexes found on microbes?
Alternative pathway
What type of pathway activates the complement system when a macrophage ingests a microbe which causes the liver to produce chemicals called lectin?
Lectin pathway
What 3 results occur once the complement system has been activated?
1. Phagocytosis
2. Inflammation
3. Lysis
With an initial reaction, how long does it take for the first Ab thats released (IgM) to peak?
7 days
With an initial reaction, how long does it take for the Ab that is released quickly and in great quantity (IgG) to peak?
10 days
What are the four different types of immunity?
Natural
Artificial
Active
Passive
What does it mean when there is natural immunity?
There has been no medical intervention
What does it mean when there is artificial immunity?
That there has been medical intervention
What does it mean when there is active immunity?
The person makes Ab or activated T cell - MEMORY RESULTS
What does it mean when there is passive immunity?
The person is given/receives Ab - NO MEMORY RESULTS
What are the four ways that someone can acquire immunity?
Natural active
Natural passive
Artificial Active
Artificial passive
What immunity is it called when a patient contracts a disease or encounters an An, recovers and has memory
Natural active
What immunity is it called when IgG crosses the placenta or IgA goes from breastmilk to a newborn?
Natural passive
What immunity is it called when someone receives a vaccination?
Artificial active
What immunity is it called when someone receives Ab intraveneously?
Artificial passive
What 2 skills/traits are critical for T cells to have and are developed in the thymus?
1. Recognize MHC antigens (self-recognition)
2. Lack reactivity to your own peptide fragments (self-tolerance)
What type of selection is self recognition developed by?
Positive selection
What type of selection is self tolerance developed by?
Negative selection
What type of selection occurs in the thymus to T cells that is a weeding out process that involves dendritic cells at the cortex/medulla junction of the thymus?
Negative selection of Self tolerant T cells
How does a mother who is Rh - prevent sensitzation in order for her second Rh+ baby to be ok?
Mother is given antiRh