Lesson 2: the immune system

• Nonspecific immunity is the body's first line of defense against pathogens
• they are called Nonspecific defenses because they are not aimed at a specific pathogen
• Nonspecific immunity helps to prevent and slow the progression of a disease
• the Immune System is a series of defenses that guard against disease.
• Barriers are found in the areas of the body where pathogens might enter
• Dead skin cells (unbroken skin) help protect against invasion by microorganisms
• skin barrier refers to the outermost layer of your skin.
• skin barrier provide protection from pathogens.
• Symbiotically bacteria on skin produce acids that inhibit many pathogens
• Saliva ,Tears , and Nasal secretions Contain the Enzyme lysosome which breaks down bacterial cell wall
• Mucus are found in the inner surface of the body
• mucus Blocking bacteria from stick to inner epithelial cells
• cilia also line in the airway there beating motion sends any bacteria caught in the mucus away from the lung
• Stomach HCl, kills many microorganism found in food that could cause disease
• Cilia are hair-like structures on the surface of certain cell
• Phagocytosis is the process by which phagocytic cells surround and internalize the foreign microorganisms.
• The phagocytes release digestive enzymes and other harmful chemicals from their lysosomes, destroying the microorganism.
• complement proteins are Present in the blood plasma but are inactive.
• complement proteins are Activated by pathogens.
• complement proteins help the phagocytic cell bind better to pathogens and activating the phagocytosis.
• Interferons are proteins released by virus-infected cells
• Interferons Stimulate neighboring cells to produce antiviral proteins

  Prevent viral replication in neighboring cells
• Interferons can prevent viral replication in neighboring cells
• Complement Proteins enhance the ability of antibodies and phagocytic cells to clear microbes and damaged cells, promote inflammation, and attack the pathogen's cell membrane.
• Macrophages are phagocytosis blood cells that ingest bacteria and remove dead neutrophils and other debris.
• neutrophils are the Most abundant type of white blood cell in humans, found in the bloodstream and tissues.
• neutrophils are phagocytosis blood cells that ingest bacteria ( they die afterward)
• lymphocytosis are specific immunity (antibodies and killing of pathogens): blood cells that produce antibodies and other chemicals.
• another name for the nonspecific immune system is the innate immune system
• another name for the specific immune system is the adaptive system.
• Lymphocytes are a type of white blood cells that are produced in red bone marrow.
• The lymph nodes filter the lymph and remove foreign materials from the lymph.
• The tonsils form a protective ring of lymphatic tissue between nasal and oral cavities, which helps protect against bacteria and other harmful materials in the nose and mouth.
• the spleen stores blood and destroys damaged red blood cells. It also contains lymphatic tissue that responds to foreign substances in the blood.
• the thymus gland is located above the heart. It plays a role in activating a special kind of lymphocyte called T cells.
• T cells are produced in the bone marrow, but they mature in the thymus gland.
• Antibodies are protein produce by B lymphocytes that specifically react with a foreign antigen
• Antibodies are Y-shaped proteins consisting of four polypeptide chains: two identical heavy chains and two identical light chains.
• An antigen is a substance foreign to the body that causes and immune response, it can bind to an antibody or T cell.
• B cells are located in all lymphatic tissue and can be though of as an antibody factor