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PERFORMANCE TASK - Coggle Diagram

- - - - Lymph capillaries occur in tissues of almost all organs (except the brain, spinal cord and eyes) they resemble blood capillaries in that they branch extensively throughout the body and their walls are only one cell thick, but their walls are somewhat larger in diameter and more permeable to large molecules
    - - Humans have one or 2 L of lymph fluid its composition similar to blood but lymph lacks red blood cell and has less blood proteins its composition is about the same as a tissue flute
    - - Lymph drains into the blood circulation via the right lymphatic duct and thoracic duct, left lymphatic duct that join the right subclavian vein and left subclavian vein, respectively. The right lymphatic duct drains the right side of the head and thorax and right arm . The thoracic duct drains the remainder of the body.
    - - Include the lymph nodes, spleen, times, tonsils, adenoids and patches of tissue in the small intestine and appendix.
        These organs and tissue patches are production centers of infection and fighting cells including lymphocytes.
        They also are sites for some defense responses.
        Like all white blood cells, lymphocytes are derived from stem cells in bone marrow.
        The derivate cells enter the blood and take up residence in lymphoid organs.
        With proper stimulation, they divide by mitosis.
        The largest lymphoid organ , the spleen, has functions that include production of lymphocytes and destroying foreign particles.
        A lymph node is a bean-shaped organ of the lymphatic system, distributed widely throughout the body including the armpit and stomach and linked by lymphatic vessels
- - - - When the inflammatory response defense is insufficient, the pathogens are destroyed by the last line of defense the immune system. It recognizes, attacks, destroys and remembers each kind of pathogen that enters body. It does this by producing antibodies and specific cells that bind and inactivate pathogens.
        
        Antigen - any substance that can cause an immune response by lymphocytes.
        
        Lymphocytes- are white blood cells that spend most of their time in tissues and organs of the lymphatic system, are responsible for adaptive immunity, and originate from stem cells in the bone marrow.
        
        B lymphocytes continue developing in bone marrow.
        
        T lymphocytes develop further in the thymus
      - HUMORAL (ANTIBODY-MEDIATED) IMMUNITY
        
        Humoral immunity is provided by B cells and antibodies that they secrete into the blood that attack pathogens outside the body cells.
        B cells produce specific antibodies to destroy pathogens.
        Antibody is a protein produced by B cells.
        Any substance that causes body to produce antibody is known as antigen.
        For example proteins on the surface of pathogens and polysaccharides and toxins produced by bacteria
        Some activated B cells remain as memory cells.
        If the same antigen enters the body again, the memory cells will make the antibody to destroy it.
      - CELL - MEDIATED IMMUNITY
        
        Cell mediated immunity is produced by a type of T cell called the cytotoxic T cells that attacks infected body cells, killing both the cell and any pathogens inside it.
        They promote phagocytosis by other white blood cells and by stimulating the cells to produce antibodies.
    - - Non-specific immunity is present before any exposure to pathogens and is effective from the time of birth
        
        FIRST LINE DEFENSES (ANATOMIC BARRIERS)
        
        Against pathogens human body involves several kinds of physical and chemical barriers .
        Sweat, tears and saliva contain chemicals that kill some bacteria.
        The low pH of skin and stomach acid destroy pathogens.
        
        SECOND LINE DEFENSE
        
        If a pathogen is able to pass the first line defense and starts an infection, second line defense become activated
        
        Natural killer cells:
        
        They attack body's own cells that have become cancerous or have been invaded by viruses.
        
        Interferons
        
        When the pathogen is a virus, the infected cells produce a protein, called interferon, which causes nearby uninfected cells to produce enzymes that block the reproduction of viruses and activate macrophages.
        
        Phagocytes:
        
        Phagocytes are white blood cells , which ingest foreign invaders and cellular debris by phagocytosis. Three important types of phagocytes are : macrophages, neutrophils , dendritic cells.
        
        Inflammatory response
        
        A reaction of the body that causes swelling, redness , warmth and pain in the area of infection.