ex. 35 [lymphatic system and immune response]

• main functions of lymphatic system

  • return leaked tissue fluid
  • filters debris and foreign substances "policing"
  • site for lymphocytes multiplication
• lymphatic capillaries carry leaked fluid to collecting vessels then trunks
• right lymphatic drain upper right extremity, head, and thorax from jugular, subclavian and bronchomediastinal trunks
• thoracic duct receives lymph from rest of body
• cisterna chyli is the enlarged terminus of thoracic duct and receives fatty lymph from digestive organs
• lymphatic vessels have three tunics and valves like veins but have thinner walls, more valves, and more anastomose (branching)
• innate immune system

  • fast acting
  • surface barriers
  • internal defenses (phagocytes, inflammation and fever)
• adaptive immune responses characteristics

  1. memory
  2. specificity
  3. self-tolerance
• cells that recognize antigens and initiate adaptive immune response are lymphocytes
• immunocompetent lymphocytes have receptors on cells surface allowing for binding to antigens which provides specificity
• autoimmune diseases: Grave's disease, rheumatoid arthritis, myasthenia gravis, multiple sclerosis and diabetes mellitus
• primary lymph organs are red bone marrow and thymus
• secondary lymphoid organs and tissues are lymph nodes, spleen, tonsils and appendix
• immunocompetence involves addition of receptors on cell surface that recognize and bind to specific antigen
• b lymphocytes

  • humoral immunity
  • mature in red bone marrow
  • effector cells is plasma cells which create antibodies
• t lymphocytes

  • cellular immunity
  • mature in thymus
  • effector cells are cytotoxic t cells (attack), helper t cells (activate cells), regulatory t cells (prevent autoimmunity)
• clonal selection occur in secondary lymphoid organs where an antigen will bind to a receptor on the cell surface causing cloning with the same-antigen specific receptor; later will differentiate into memory, effector, or regulatory cells
• heavy and light chains have a constant region and variable region; variable regions is antigen-binding site to fit an antigenic determinant
• binding of immunoglobulins to complimentary antigens immobilize antigens and they are phagocytized or lysed by complement fixation
• Ouchterlony double-gel diffusion technique detects presence of particular antigens in sera or extracts; anitgen-antibody reaction created precipitin line
• Lymph organization

  • lymph capillaries
  • collecting lymphatic vesicles
  • lymph nodes
  • lymph trunk
  • lymph duct
• circulatory system moves blood throughout the body, delivering it to the heart but the lymphatic system move fluid from interstitial spaces to the circulatory system; lacking contractile “heart” and arteries making it one way
• Lymphatic capillaries branch through nearly all tissues of the body to pick up leaked fluid
• Lymph has proteins, salts, glucose, fats, water, and white blood cells with the occasional germ or bacteria to be phagocytized; no red blood cells
• Self-tolerance ensures that our own proteins are tolerated by the immune system and we do not attack ourselves
• adaptive immune system memory of previously encountered foreign antigens is remarkably accurate and highly specific in its attacks to that specific antigen
• b and T cells originates on the red bone marrow and they migrate to the thymus for T cell maturation and bone marrow for B cell maturation
• Five immunoglobulin subclasses (My Girl Don’t Act Extra)

  • IgM
  • IgG
  • IgD
  • IgA
  • IgE
• Antibodies inactivate foreign substances by binding to them while signaling complement system to attack
• antigens are molecules that are foreign to the body and trigger an immune response
• lymph node

  A) afferent vesselsn

  B) lymphoid follicle

  C) germinal center

  D) subcapsular sinus

  E) efferent vessels

  F) hilum

  G) medullary cord

  H) medullary sinus

  I) trabeculae

  J) capsule

  
• lymph node

  A) trabeculae

  B) capsule

  C) lymphoid follicle

  D) medullary sinus

  E) medullary cord

  
• spleen

  A) capsule

  B) trabeculae

  C) splenic cords

  D) splenic sinusoids

  E) arterioles and capillaries

  F) red pulp

  G) white pulp

  H) central artery

  I) splenic artery

  
• spleen

  A) capsule

  B) red pulp

  C) white pulp

  
• palatine tonsil

  A) tonsillar crypt

  B) germinal centers in lymphoid follicles

  
• lymphatic diagrams

  A) right lymphatic duct

  B) thoracic duct

  C) subclavian veins