Lymphatic

• Tonsils

  • Small masses of lymphoid tissue around the pharynx
  • Trap and remove bacteria and other foreign materials
  • Tonsillitis is caused by congestion with bacteria
• Peyer's Patches

  • Found in the wall of the small intestine
  • Resemble tonsils in structure
  • Capture and destroy bacteria in the intestine
• IgG

  • They makes up approximately 80% of the serum antibodiesThey has a half-life of 7-23 daysIgG is a monomer and has 2-epitope binding sites
  • This is the only class of antibodies that can cross the placenta and enter the fetal circulation

  Functions

  1. Immunity to new born ii.
  2. Neutralization of Toxins
  3. binds to Fc receptor by Phagocytosis
• IgM

  • They makes up approximately 13% of the serum antibodies
  • Most of the IgM are pentamer and has 10 - epitope binding sites. some are monomer
  • They has a half-life of about 5 days
  • It is the first immunoglobulin class produced in a primary response to antigen

  functions

  1. Activation of classical pathway
  2. Defense against multivalent antigens
  3. Act as Opsonin
• IgA

  • They makes up approximately 6% of the serum antibodies
  • They has a half-life of approximately 5 days
  • IgA is a dimer and has 4-epitope binding sites
  • They found mainly in body secretions such as saliva, mucous, tears, colostrum and milk

  Functions

  1. It as a Secretory antibody
  2. Effective against virus that causing Influenza
  3. Production to Infant gut
• IgD

  • They makes up approximately 0.2% of the serum antibodies
  • is a monomer and has 2-epitope binding sites
  • This class antibodies are found on the surface of B-lymphocytes

  Function

  • B cell activation
  • Act a receptor for antigen binding
• IgE

  • It was discovered in 1966 by K. Ishizaka.
  • It is very low concentration in blood(17-450ng/ml)
  • It contain small percentage of Lympocytes

  Functions

  1. Responsible for Immediate hypersensitivity
  2. Binds to Fc receptor on basophils and mast cells iii. Release of substance like histamine ,vasoactive mediators
• IgM

  • Biological functions
  • Membrane-bound immunoglobulin on the surface of immature and mature B cells
  • First antibody produced in a primary response to an antigen
  • First antibody produced by the fetus
  • Efficient in binding antigens with many repeating epitopes, such as viruses
  • Classical complement activation
• IgD

  • Membrane-bound immunoglobulin on the surface of mature B cells
  • No biological effector function known
• IgA

  • Predominant antibody class in secretions (saliva, tears, breast milk) and mucosa
  • First line of defence against infection by microorganisms
• IgG

  • Most abundant class with four isotypes - IgGI, IgG2, IgG3, IgG4
  • Crosses the placenta
  • Opsonization
• IgE

  • Defence against parasite infections
  • Associated with hypersensitivity reactions (allergies)
  • Found mainly in tissues
• Components of the Lymphatic System

  • Lymph Fluid
  • Lymph Vessels
  • Lymphatic Organs
  • Lymphoid Tissue and Cells
• Lymph Fluid


  Excess tissue fluid carried by lymphatic vessels
• Lymph Vessels


  Transport lymph towards the heart
• Lymphatic Organs

  • Lymph nodes
  • Tonsils
  • Spleen
  • Thymus
• Lymphoid Tissue and Cells

  • White blood cells
  • Bone marrow
  • Thymus
  • Spleen
  • Lymph nodes
• Functions of the Lymphatic System

  • Transport Fluids
  • Body Defense
  • Fat Absorption
• Transport Fluids


  Returns fluids back to the blood
• Body Defense


  Plays essential roles in immune defense and disease resistance
• Fat Absorption


  Absorbs digested fats at the intestinal villi
• Lymphatic Vessels


  • One-Way System: Moves lymph towards the heart without a pump
  • Movement Mechanism: Milking action of skeletal muscles and rhythmic contraction of smooth muscle in vessel walls facilitate lymph movement
• Components of Lymph

  • Water
  • Blood cells
  • Proteins
  • Various other substances
• Materials Returned to Blood

  • Water
  • Blood cells
  • Proteins
  • Electrolytes
  • Urea
  • Creatinine
  • Amino acids
  • Other substances
• Harmful Materials in Lymph

  • Bacteria
  • Viruses
  • Cancer cells
  • Cell debris
• Lymph Nodes


  Filter lymph before it is returned to the blood, containing macrophages and lymphocytes for immune response
• Spleen


  • Filters blood
  • Destroys worn-out blood cells
  • Forms blood cells in the fetus
  • Acts as a blood reservoir
• Thymus


  • Located over the heart
  • Functions primarily during childhood to produce hormones (e.g., thymosin) that program lymphocytes
• Tonsils


  • Trap and remove bacteria and other foreign materials
• Peyer's Patches


  • Found in the wall of the small intestine, capture, and destroy bacteria in the intestine
• Mucosa-Associated Lymphatic Tissue (MALT)


  Includes Peyer's patches, tonsils, and other lymphoid tissue that protect respiratory and digestive tracts
• Body Defense Mechanisms

  • Non-Specific Defense
  • Specific Defense (Immune System)
• Non-Specific Defense


  Includes barriers like skin and mucous membranes, and general responses like inflammation
• Specific Defense (Immune System)


  Recognizes specific antigens and remembers previous encounters to mount stronger responses
• Types of Immunity

  • Humoral Immunity
  • Cellular Immunity
• Humoral Immunity


  Involves B cells producing antibodies
• Cellular Immunity


  Involves T cells targeting virus-infected cells
• Inflammatory Response

  • Triggers: Injury to body tissues
  • Signs: Redness, heat, swelling, and pain
  • Functions: Prevents spread of damaging agents, disposes of cell debris and pathogens, and sets the stage for repair
• Cells Involved in Immune Response

  • Phagocytes (Neutrophils and macrophages)
  • Natural Killer Cells
  • Dendritic Cells
• Phagocytes


  Neutrophils and macrophages that engulf foreign materials