Lymphatic System & Blood Typing (LAB PRACTICAL) Flashcards
Two parts of lymphatic system
-Lymphatic vessels
-Lymphoid tissues and organs
General functions of the lymphatic system
-Transport escaped fluids back to the blood
-Plays essential roles in body defense and resistance disease
-Plays a role in digestion
Lymph
Fluid carried by lymphatic vessels
Lymph node function
-Filter lymph before it is returned to the blood
-Contains defense cells (Macrophages & Lymphocytes)
Role of valves in lymphatic system
Prevents backflow of lymph
3 properties of lymphatic vessels
-Lymphatic vessels are a one-way system that moves lymph towards the heart
-There is no heart-like pump to move lymph
-“Skeletal muscle pump” moves lymph through vessels as skeletal muscles undergo squeezing motion
Role of macrophages
Engulfs and destroys foreign substances
Role of lymphocytes
Provide immune response to antigens
Medulla
-Inner part
-Contains macrophages (Phagocytic cells)
Cortex of lymph node
-Exterior portion
-Contains follicles that house collections of lymphocytes
Lymphatic vessels
-Collect lymph from lymph capillaries
-Carry lymph towards and away from lymph nodes
-Return fluids to circulatory veins near the heart (Right lymphatic duct & thoracic duct)
Flow of lymph through nodes
-Lymph enters convex side through AFFERENT lymphatic vessels
-Lymph flows through a number of sinuses inside the node
-Lymph exits through EFFERENT lymphatic vessels
-Fewer efferent than afferent vessels causes flow to be slowed
Red bone marrow
-Site of lymphocyte production as they contain hematopoietic stem cells (Not T lymphocytes)
-Where B cells mature
Spleen
-Filters blood and destroys worn-out blood cells
-Forms blood cells in fetus
-Acts as blood resevoir
Tonsils
-Small masses of lymphoid tissue around pharynx
-Trap and remove bacteria and other foreign material
-Congestion of bacteria can cause tonsillitis
Thymus
-Produces hormones (Like thymosin) to program lymphocytes
-Maturation site for T lymphocytes
-Functions at peak level only in childhood
Peyer’s patches
-Aggregated lymphoid nodules in small intestine that capture and destroy bacteria
-Similar to tonsils in structure
Appendix
Resevoir for gut bacteria; may assist in B cell maturation
Secondary lymphoid tissues and organs
-Spleen, lymph nodes, tonsils, adenoid, appendix, Peyer’s patch
B cell
Lymphocyte that resides in lymph nodes, spleen, or other lymphoid tissues where it is induced to replicate by antigen-binding and helper T cell interactions; its progeny (clone members) form plasma cells and memory cells
Plasma Cell
Antibody producing “Machine”; produces huge numbers of the same antibody, represents further specialization of b cell clone descendants
Helper T cell
-A T-cell that binds with a specific antigen presented by a macrophage -Stimulates the production of other immune cells (Cytotoxic T cells and B cells) to help fight the invader
-Acts both directly and indirectly by releasing cytokines
Cytotoxic T Cell/Killer T cell
-Enhanced by helper T cell
-Specialty is killing virus-invaded body cells and body cells that have become cancerous
-Involved in graft rejection
Regulatory T cell
Slows or stops the activity of B and T cells once the infection has been conquered. Thought to be important in preventing autoimmune disease.
Memory Cell
Descendant of an activated B cell or T cell; generated during the initial immune response; may exist in the body for years thereafter, enabling it to respond quickly and efficiently to subsequent infections or meetings with the same antigen
Antigen-presenting cell
-Any of several cell types that engulfs and digests antigens that it encounters and presents parts of them on its plasma membrane for recognition by T cells bearing receptors for the same antigen.
-Essential in cell-mediated response
Plasma Cells (Effector B cells)
Produce antibodies/immunoglobulins
Antibody function
-Binds to specific antigen
-Aid in inactivation or destruction
Antibody Structure
-Four amino acid chains are linked by disulfide bonds
-Two identical A.A chains are linked to form the heavy chain
-The other 2 chains will form the light chain
-2 specific antigen binding site
-Constant region same within a class of antibodies
IgD
-Always attached to B cell
-Believed to be cell surface receptor of immunocompetent B cell and important in B cell activation
IgM
-Attached to B cell, free in plasma
-Serves as antigen receptor when bound to B cell
-1st Ig to be released during primary response
-Potent agglutinating agent
IgG
-Most abundant (75-85% of circulating antibodies)
-Main antibody of both primary and secondary responses; crosses placenta and provides passive immunity to fetus
-fixes complement.
IgA
-Monomer in plasma; dimer in secretion (Saliva, tears, milk)
-Bathes and protects mucosal surfaces from attachment of pathogens
IgE
-Secreted by plasma cells in skin, mucosae in GI and respiratory tract, and tonsils
-Binds to mast cells and basophils, and triggers release of histamine and other chemicals that mediate inflammation and certain allergic reactions
Blood type A
-A antigens
-Anti B antibodies
-Can receive Type A and Type O blood
Blood type B
-B antigens
-Anti A antibodies
-Can receive type B and Type O blood
Blood Type AB
-Both A and B antigens
-No anti A or anti B antibodies
-AB+ is universal recipient and can receive all blood types
Blood Type O
-No A or B antigens
-Both anti-A and anti-B antibodies
-Universal donor
-Can only receive O
