CCMA training notes: Lymphatic System Review

  • Lymphatic system  

  • Anatomy  

  • The Lymphatic System  

  • Lymphatic circulation: works closely with cardiovascular circulation to move lymph and lymph cells throughout the body. It depends on the pumping action of the muscles and flows in only one direction. From its point of origin, it moves upward until it returns to the circulatory system at the base of the neck through lymphatic vessels. 

  • Lymph: is filtered by lymph nodes located periodically along the lymphatic vessels.  

  • Right Lymphatic Duct: collects lymph from the right side of the head and neck, the upper right quadrant of the body, and the right arm. It empties into the right subclavian vein. 

  • Thoracic Duct: collects lymph from the left side of the head and neck, the upper left quadrant of the trunk, the left arm, the lower portion of the trunk, and both legs then empties into the left subclavian vein. 

  • Lymph and Lymph Nodes  

  • Lymph: is made up of interstitial fluid (also known as tissue fluid or the fluid that is found between the cells.  

  • Fluid delivers oxygen, nutrients, and hormones to the cells and then picks up waste produced and protein molecules that were created in the cells.  

  • It cooperates and coordinates closely with the immune system and cardiovascular system. 

  • It collects protein molecules, removes dead cells and debris, and removes pathogens. 

  • There are up to 700 lymph nodes in the body. Clusters are found under the arms, in the groin, in the neck, in the chest, and in the abdomen. 

  • A lymph node is a small, bean-shaped filtering node that contains highly specialized lymphocytes (lymph cells) that can destroy pathogens. Lymph flows into the nodes and the pathogens the lymph have collected in the body are destroyed. Pathogens include bacteria, viruses, malignant cells, etc. This is why lymph nodes swell when one is sick. The node can remove other types of impurities as well. Once filtered, the lymph is eventually dumped into the venous circulation. 

  • There are three major groups of lymph nodes:.  

  1. Cervical lymph nodes:  

  1. Axillary lymph nodes:  

  1. Inguinal lymph nodes 

  • Lymph Vessels 

  • Lymphatic capillaries: These are microscopic tubes that are sealed at one end. They are found near the surface of the body. The walls are only one cell thick. The cells separate briefly so that lymph from between the cells can enter the capillary, then they close and force the lymph to flow upward and forward. 

  • Lymphatic vessels: The lymphatic capillaries get progressively larger until they become lymphatic vessels. 
    These are located deeper in the tissues. They include valves to prevent back-flow of the lymph. 

  • Lymphatic ducts: Lymphatic vessels become larger and eventually join together to form two ducts. Each duct drains a specific body area and returns the lymph to venous circulation. 

  • Lymphocytes  

  • Are lymph cells formed in bone marrow and they work to defend against antigens, which is any substance that the body sees as foreign, such as viruses, bacteria, toxins, and tissues that have been transplanted. 

  • As they are formed in the bone marrow and mature, they differentiate into lymphoid tissues throughout the body. Differentiate means to change so that they can perform a specific function. There are three kinds of lymphocytes: 

  1. Natural killer cells: NK cells play an important role in killing cancer cells and cells infected by viruses.  

  1. B-cells: Are also called B lymphocytes. They are specialized cells that produce antibodies. Each lymphocyte makes a specific antibody that destroys a specific antigen. They are most effective against viruses and bacteria. 

  1. T-cells: Are also called T lymphocytes. They play an important role in cell-mediated immunity and release cytokines including interferons and interleukins. Interferons respond particularly to viruses or tumor cells, and interleukins are important in directing B and T cells to divide and proliferate. 

 

  • Other Lymphocytic Structures  

  • The Tonsils: Are made of three messes of lymphoid tissue that form a ring around the back of the nose and upper throat. They help prevent pathogens from entering the respiratory system when breathing through the nose and mouth. There are nasopharyngeal tonsils (adenoids), palatine tonsils, and lingual tonsils.  

  • The Thymus Gland: The thymus gland is a mass of lymphoid tissue found above the heart. It is largest during puberty and then decreases in size and function with age. It secretes a hormone that stimulates the maturation of lymphocytes into T-cells.  

  • The Vermiform Appendix: The appendix hangs from the lower portion of the cecum of the large intestine. It may play an important role in the immune system.  

  • The Spleen: A mass of lymphoid tissue found in the upper left quadrant of the abdomen inferior to the diaphragm and posterior to the stomach. It filters microorganisms and other foreign materials from the blood. It forms lymphocytes and monocytes (specialized leukocytes, or white-blood cells). The spleen also destroys worn-out erythrocytes (red blood cells).  

  • Physiology 

  • The Immune System  

  • The Skin: Is the body’s first line of defense against foreign substances. It forms a protective barrier around the body.  

  • The Respiratory System: It traps foreign particles that are inhaled into the body. It uses nose hairs and moist mucous membrane lining throughout the respiratory system.  

  • The Digestive System: Uses acids and enzymes produced by the stomach to destroy invaders that are swallowed or consumed.  

  • The Lymphatic System: Including the leukocytes work to attcak and destroy pathogens that have gotten past the protective barriers  

  • Antigens and Antibodies  

  • Antigen: any substance that the body regards as being foreign, such as a virus, bacteria, toxin, or transplanted tissues or organs  

  • Antibody: Is a disease-fighting protein created by the immune system designed to respond to the pressence of a specific antigen.  

  • Antigen Antibody Reaction: the immune reaction refers to the reaction where the antibody binds to the antigen, labeling it as dangerous thus other cells in the immune system can recognize the danger and destroy the foreign body. The antibodies may also be able to neutralize foreign antigens.  

  • Immunoglobulins: Bind with specific antigens in the antigen-antibody response. There are 5 main types each having a different purpose and is active against specific types of foreigninvaders such as...  

  1. Immunoglobulin G (IgG) 

  1. Immunoglobulin A (IgA)  

  1. Immunoglobulin M (IgM) 

  1. Immunoglobulin D (IgD)  

  1. Immunoglobulin E (IgE)  

  • Phagocytes: are specialized leukocytes that act as part of the antigen-antibody reaction. They destory cell debris, dust, pollen, and pathogens. There are several types:  

  • Monocytes: These leukocytes defend against many infectious organisms. They also produce macrophages.  

  • Macrophages: These leukocytes surround and destroy invading cells and remove dead cells  

  • Dendritic cells: These leukocytes petrol the body searching for antigens that produce infections. Once found, the dendritic cells swallow it and then alert B and T cells to act against this specific antigen.  

  • The Complement System: Is a ground of proteins that normally circulate in the blood in an inactive form. Then when needed, these cells complement the ability of the antibodies to defend against the pathogens. They combine iwth them to dissolve and remove pathogenic foreign cells.  

  • Immunity: Is the state of being resistant to a specific disease and can be natural immunity also called passive immunity or through a vaccine.  

  • Vaccine: Is designed to protect against the disease.  

  • Common Diseases and Disorders 

  • Spleen Disorders  

  • Hypersplenism: Is an overactive spleen and removes the blood cells too early and too quickly.  

  • Splenomegaly: Is a larger than normal spleen and it can be caused by malaria, Hodgkin's disease, leukemia, heart failure, cirrhosis, tumors, infections, lupus or rheumatoid arthristis, and sickle disease.  

  • Lymphedema  

  • Refers to the selling of the tissues because of an abonormal accumulation of lymph fluid within the tissues.  

  • Caused by damage to the lymphatic system so that the lymph doesn't drain properly.  

  • Allergic Reactions  

  • Examples of allergens: pollen, food, and animal dander 

  • Allergy: is called a hypersensitivity to the allergen and refers to an overreaction by the body to the allergen, or the substance that produces the allergic reaction. The allergen produces an antigen that initiates the immune response which can be either...  

  • A Localized Allergic Response: Redness, itching, or burning where the skin has come into contact with the allergen.  

  • A Systemic Allergic Response: Causing a mild to severe and potentially fatal reaction, or anaphylactic shock.  

  • Autoimmune Disorders  

  • Refers to any disease characterized by a condition in which the immune system by a condition in which the immune system produces antibodies against its own tissues in which the body mistakes healthy cells, tissues, or organs for foreign substances or antigens.  

  • There are several different types of autoimmune disorders:  

  • Graves’ disease 

  • Scleroderma  

  • Multiple sclerosis  

  • Crohn’s disease  

  • Pernicious anemia  

  • Immunodeficiency Disorders  

  • Severe combined immunodeficiency (SCID): Refers to an inherited condition in which the malfunctioning immune system causes an increased susceptibility to infection and failure to thrive. Newborns are normally screened for SCID.  

  • HIV  

  • Refers to human immunodeficiency virus. This is a bloodborne infection where the virus damages or kills the T-cells of the immune system. This leads to the falling of the immune system. Accordingly, without the immune system’s protection, the body is at risk of developing life-threatening infections.  

  • Acquired Immunodeficiency Syndrome (AIDS): Is most advanced stage of an HIV infection and though medical advances have helped manage HIV infection and AIDS, AIDS is fatal.  

  • Lymph Node and Vessel Disorders  

  • Lymphadenitis: Is also called swollen glands and refers to an inflammation of the lymph nodes or lymph glands.  

  • Lymphadenopathy: This is any disease process that impacts a lymph node or nodes.  

  • Lymphangioma: This is a benign tumor formed by an abnormal collection of lymphatic vessels because of a congenital malformation of the lymphatic system.  

  • Tonsillitis  

  • Is an inflammation of the tonsils leading to swollen tonsils, sore throat, difficulty swallowing, tender lymph nodes in the neck, and potentially.  

  • Bacterial Infections  

  • Cellulitis: Bacterial infection that leads to painful, red infection and can occur anywhere in the body.  

  • Folliculitis: An infection of the hair follicles causing red, swollen bumps similar to pimples.  

  • Impetigo: This infection causes oozing sores, typically in children.  

  • Food Poisoning: There are numerous bacteria that cause different types of foodborne illnesses:  

  • Campylobacter jejuni  

  • Clostridium botulinum  

  • Escherichia coli  

  • Listeria monocytogenes  

  • Salmonella  

  • Vibrio  

  • Sexually Transmitted Diseases (STDs): Bacteria can also cause many different infections:  

  • Chlamydia  

  • Gonorrhea  

  • Syphilis  

  • Bacteria vaginosis  

  • Other Infections:  

  • Bacteria meningitis  

  • Otitis media  

  • Urinary tract infections  

  • Respiratory tract infections  

  • Fungus and Viral Infections  

  • There are numerous infections caused by viruses:  

  • Viral Pneumonia 

  • Viral maningitis  

  • Encephalitis  

  • The Common Cold  

  • Influenza  

  • Hepatitis  

  • Ebola Hemorrhagic Fever 

  • Covid 19 

  • Fungi also causes numerous infections:  

  • Cryptococcal Meningitis  

  • Mycosis Athlete’s foot (tinea pedis)  

  • Ringworm (tinea corporis)