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74 Cards in this Set

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What are the organs involved in lymphatic system?
Red bone marrow, Encapsulated tissue and diffuse lymphatic tissue.
What is included in encapsulated tissue?
Thymus, spleen, and lymph nodes.
What is included in diffuse lymphatic tissue?
Tonsils, adenoids, peyers patches, and appendixx
What are the functions of the lymphatic system? (5)
1)Surface protection
2) Drain excess interstitial fluid and plasma protein form tissue spaces.
3) Transport of dietary lipids and vitamins from GI tract.
4)Facilitate immune response
5) Acute inflamation.
How does the lymphatic system facilitate immune response?
Specify and target invading organisms
Recognize self from non-self
Activate immune system to neutralize or destroy the antigen.
WHat mediates the response of acute inflammateion?
Neutrophils (the response is always the same)
Where do T cells mature?
In the thymus.
What are primary lymphatic organs? What do they do?
Bone marrow and thymus provide an environment for stem cells to divide and mature into B and T lymphocytes.
What are secondary lymphatic organs and tissues? What happens here?
Secondary lymphatic organs and tissues are sites where most immune responses occur. Lymph nodes, spleen and lymphatic nodules are examples of these.
At what point are B cells mature?
After they leave the marrow.
When are T cells mature?
After they leave the thymus.
What mediates cellular immunity? What are the cells reacting to? What makes it different from humoral immunity?
Mediated by T lymphocytes.
These cells are reacting to foreign cells or viruses
Delayed hypersensitivity takes 1-2 days
No circulating factors are found
There is inflammation at the site.
What mediates humoral immunity? How quickly does hypersensitivity occur? What is in the circulation?
Humoral immunity is mediated by B lymphocytes and reacts to immediate hypersensitivity. There are antibodies in the circulation and they inactivate or destroy foreign substances.
In which immune reaction is there an immediate hypersensitivity?
humoral immunity
Cellular immunity is delayed.
Antibodies are required for what type of immune response?
Humoral immunity.
What circulating factors are found in cellular immunity?
NONE!
What are the 4 kinds of hypersensitivity?
Type I (allergy or anaphylaxis)
Type II (Antibody-mediated cellular destruction)
Type III (Preformed Ag-Ab complexes induce inflammatory response) (lupus, rheumatoid arthritis)
Type IV (T-cell driven: Cellular destruction (graft rejection).
What identifies helper T cells? What do helper T cells do?
Helper T cells are identified by CD4. They stimulate differentiation of B cells. They are destroyed by AIDS virus.
What identifies suppressor T-cells? What do they do?
Identified by CD8. THey inhibit action of Th cells and Tc cells (shut down response)
What identifies cytotoxic T-cells? What do they do?
Cytotoxic T cells are identified by CD8. They perform cell lysis.
What is the main role of B cells? What type of antibody is on the surface?
The main role of B cells are effectors. They have 150,000 IgM on the surface.
What do natural killer cells do? What activates them?
Natural killer cells kill virus infected and malignant cells. They do not need activation.
After B-cells become activated what do they become?
Plasma cells.
What are the functions of T-cells that mature in the thymus? What are they effective against?
Cell mediated response. Killer cells attack antigens. Helper cells cosimulate T and Bcells. They are effective against fungi, viruses, parasites, and cancer and tissue transplants.
What ist he main function of B-cells in bone marrow? What are they effective against?
B cells are antibody mediated responses. Plasma cells form antibodies and they are effective against bacteria.
What are the 2 tissue elements of the lymphatic system?
1) Reticular CT
- form stroma or framework of tissues
2) Cells in spaces between the reticular fibers
- lymphocytes, macrophates, plasma cells, antigen presenting cells.
What do plasma cells do?
Form antibodies.
What connects they lymphatic system to the blood vascular system?
Lymphatic vessels.
What divides the thymus into lobules?
Capsule and trabeculae.
Each lobule of the thymus has what?
Cortex and medulla.
What makes up the cortex in the thymus?
Tightly packed lymphocytes and macrophages.
What makes up the medulla?
Reticular epithelial cells produce thymic hormones and Hassall's corpuscles.
What are the three types of epithelial reticular cells found in the cortex of the thymus? What do each of them do?
Type I- isolate the cortex from the body (occulidng junctions)
Type II - divide cortex into lymphocyte filled pockets (desmosomal junctions)
Type III - corticomedullary junction- isolates cortex from medulla (occluding junctions.
What are the 3 types of epithelial reticualr cells found in the medulla? What do each of them do?
Type IV - corticomedullary junction
Type V - framework of medulla
Type VI - Hassall's corpuscles
Where are Hassall's corpuscles found?
IN the thymus.
What type of general celsl are found in the medulla?
Less dense lymphocytes, slightly enlarged in size and chosen for death.
What is the purpose of tolerance?
Recognize self from non self.
What are the 2 mechanisms via tolerance occurs?
1) Anergy-disabling of the immunocompentent cell
2) Killing of immunocompentent cells that would recognize self-antigens. This occurs in the thymus.
True or false. The thymic cortex is in close contact with the rest of the body.
False the thymic cortex is isolated from the body.
What are the 3 functions of type II and III epithelial reticular cells?
Antigen presenting cells, self antigens, and express MHC I and MHC II.
What are MHC I and MHC II?
Docking molecules present on B and T cells. The receptor plus the MHC molecule allow cells to do their job.
When are cells killed?
If TCR recognizes self antigens or T cell CD4 CD8 can't recognize MHC I or MHC II.
What happens to B cells taht are not cosimulated?
Inactivation (anergy of cell)
Describe the lymph nodes.
Bean shaped organs up to 1 inch long located along lymphatic vessels.
Where are lymph nodes concentrated?
Near mammary glands, axillae and groin.
What forms the stroma of lymph nodes?
Capsule, trabeculae, and reticular fibers.
What is the parenchyma of lymph nodes divides into ?
Cortex and medulla.
What is contained within the cortex of lymph nodes? What happens here?
Lymphatic nodules with germinal centers containing dendritic cells (antigen presenting cells and macrophages) B cells proliferate into antibody-secreting plasma cells.
What is contained within the medulla of lymph nodes?
B cells and plasma cells in medullary cords.
What is in the primary nodule of lymph node cortexes?
B cells that have not been activated.
What is in the secondary nodules of lymph node cortexes?
B cell region where antigen presentation has taken place. (1st step to becoming a plasma cell)
What is filtered in the node of lymph nodes??
LYMPH NOT BLOOD!
Describe the pattern of lymph flow in lymph nodes.
Flow is in one direction. Afferent vessels lead in.
Sinuses lead to efferent vessels that exit at hilus.
What does the spleen filter?
Blood not lymph!
What does the hilus of the spleen contain?
Blood and lymphatic vessels.
Where is the spleen?
Between the stomach and diaphragm.
What does the stroma of the spleen consist of?
Capsule, trabeculae, fibers and fibroblasts.
What does the parenchyma of the spleen consist of?
White and red pulp.
What is the white pulp of spleen?
White is lymphatic tissue (lymphocytes and macrophages) around branches of splenic artery.
What is the red pulp of the spleen?
Venous sinuses filled with blood and splenic tissue (splenic cords).
What are the 2 forms of circulation in the spleen? Describe them.
The open form of circuation dumps into red pulp.
The closed form of circulation is where the central artery goes directly to sinusoid.
What lines marginal zone sinuses?
Macrophages and antigen presenting cells.
What is the purpose of reticular fibers in the spleen?
Provide structural support.
What do M cells do in lymph nodules?
Antigen presentation cells, also antigen transporter cells.
Where do lymph nodules have a well defined structure?
Only in peyer's patch.
What is in the follicle of peyer's patch?
B cells
Where are peyer's patches found?
In the ileum of the small intestines.
Where are mucosa associated lymphoid tissue found?
Gastrointestinal tract, trachea, tonsils, peyer's patch, appendix, respiratory tract.
What is the functions of mucosa associated associated lymphod tissue?
Antigen presentation and phagocytosis.
What are lymphatic nodules?
Concentrations of lymphatic tissue not surrounded by a capsule. They are scattered throught out the CT of mucous membranes.
What are the 3 tonsils and where are they?
Adenoids (pharyngeal tonsils)
Palatine tonsils (on each side wall)
Lingual tonsil (in the back of the tongue).
What are lymphatic vessels and what do they do?
They are capillaries that begin as closed ended tubes. They are found in spaces between cells.
Where do lymphatic vessels empty?
Subclavian vaeins.
What keeps the lymph flowing towards the heart?
Respiratory and mucular pumps as well as valves that push them towards the thoracic duct.