Lymphatic System

• Lymphatic System

  Collection of cells and biochemicals that travel in lymphatic vessels
• Lymphatic System

  • Produced by organs and glands
  • Assist in circulating body fluids
  • Transport excessive fluid from the spaces in tissues and return in towards the bloodstream
  • Destroys infectious things
  • Immune response to the lymphatic system and it protects the bodies against cancer cells and toxins
• Lymphatic Pathways

  1. Starts off as lymphatic capillaries

  2. Starts off as a tiny vessel and over time, it forms into larger lymphatic vessels and eventually it grows and joins with the veins in the thorax
• Lymphatic capillaries

  • Are microscopic
  • Close ended tube
  • Extends to form a community that parallel them
  • Lymph Capillary walls are permeable, they form simple squamous cells allowing tissue fluid to enter the lymphatic capillaries
  • The fluid is called the lymph
• Lymphatic vessels

  • Have a flap like valves just like the blood vessels that help with the backflow of blood
  • Afferent lymphatic vessels is where it goes into a lymph node
  • Efferent vessels are where it exits a lymph node
• Lymph

  • The fluid lymph came from blood plasma
  • It enters in a lymphatic capillary
  • Made of water and dissolved substances, it left the blood capillaries by filtration, caused as capillary pressure force water and small molecules out of the plasma
• Lymph Nodes

  • Small organs covered by lots of connective tissue
  • Have lots of lymphocytes and macrophages to fight foreign microorganisms
  • Found in group of chains along paths of the large vessels
  • Filter harmful particles and make lymph before returning it to the bloodstream
  • Monitor body fluids
  • Main headquarters for producing lymphocytes, bone marrow and thymus glands
  • Its lymphocytes would attack virus, bacteria and parasitic cells that would bring them to the lymph nodes
  • Macrophages engulf and destroy foreign things, damaged cells and debris
  • Are in the thoracic, cervical, pelvic, inguinal area
• Lymph movement

  1. Hydrostatic pressure

  2. Osmotic pressure

  3. Breathing

  4. Skeletal muscle contractions and smooth muscle in the lymphatic vessels
• Thymus Glands

  • Lower part of the throat, overlying the heart
  • At peak during childhood
  • Produce hormones to control lymphocytes
• Spleen

  • Left side of the abdomen
  • Filter blood
  • Destroy worn out blood cells
  • Form blood cells in the fetus
  • Blood reservoir
• Lymphatic Trunk


  1. Drains lymph from the vessels

  2. Serve and join ducts

  3. Thoracic Duct starts near the lower part of the spine, gets lymph from the pelvis, abdomen and lower chest, runs through the chest and empties into the blood through a vein near the left side of the neck

  4. Right lymphatic duct collect lymph on the right side of the neck, chest and arm, goes into a large vein somewhere around the right side of the neck
• Complement


  • Proteins in plasma and other body fluids that interact in a series of reactions
  • When it is activated, it stimulates inflammation, attracts phagocytosis and growth of tumors
• Interferon


  • A hormone that respond to viruses and tumor cells
  • When it's released, interferons bind receptors on uninfected cells stimulating synthesizing proteins and a variety of viruses
  • Stimulate phagocytosis
  • Enhance the activity on other cells to resist infections and prevent the growth of tumors
  • Produced by macrophages and lymphocytes to bind to receptors
• Types of tissue transplants

  • Autografts - tissue transplanted from one site to another on the same person
  • Isografts - tissue from an identical twin
  • Allografts - tissue taken from a non related person
  • Xenografts - tissue taken from a different animal species ex: pig
• Pathogen


  The presence and multiplying number of a disease causing agent that may cause an infection
• Types of Antibodies


  • IgG: Against bacteria and toxins, usually in plasma and tissue fluids, activates complement
  • IgA: Found in breast milk, tears, nasal fluid, bile and urine, help launch an arsenal against diseases, help eye infections, stomach, nasal fluid
  • IgM: Antibodies A and B, blood transfusions, activate complement
  • IgD: Found on surfaces of the B cells (bone marrow cells)
  • IgE: Found in allergies
• Phagocytosis

  Removes foreign particles from the lymph, engulfs foreign particles into a vacuole
• Fever

  Body temperature that is above the average body temperature, makes the body inhospitable to pathogens
• Inflammation


  Response to infection, producing localized redness (increases blood flow and volume), swelling, heating and pain
• Antibodies

  Second Line of Defense: Inflammatory Response, Produces by redness, heat, swelling and pain, Histamine was released, Blood vessels vasodilate, Fibrin enters tissue