Anatomy and Physiology 2 Study Guide 3 Immune System 1 Define the immune system and its 3 lines of defense The immune system is the body s defense system It protects us against any threat to our body There are three lines of defense that work together to destroy any threat These defense lines are divided into two intrinsic defense systems but they depend on each other The first system is the innate immune system non specfic This system contains the first two lines of defense the external membranes skin mucosa etc and the inflammatory system macrophages proteins etc Both of these lines act within minutes of a threat The second system is the adaptive immune system specific this is the third line of defense This system with the T cellular and B humoral cells is very specific to a certain virus bacteria This system takes days to get into action So the immune system is divided into the innate and the adaptive systems and there are three lines of defense the external membranes the inflammatory response and the specific immunity with B and T cells 2 Explain how the innate and adaptive systems are intertwined These systems one that attacks foreign substances within minutes and one that takes days to weeks to act are intertwined When the innate system releases proteins to attack the foreign substances some go to alert cells in the adaptive system of a presence of a foreign substance So the innate system telling the adaptive system to get ready that a foreign substance is in the body Tony Berardi 3 What are surface barriers and how do they function as the first line of defense The innate system has the first and second line of defense The first line of defense is all the surface barriers The skin protects us every day from many foreign substances The mucus membranes lining our stomach and other organs also secrete chemicals to kill bacteria and toxins it lines all body cavities that open exteriorly A little cut can enable internal innate The skin is strong because of a protein called keratin this serves as a tough hardening barrier to outside substances and resistant to weak acids bases and pollution The mucous membranes line most organs that open to the exterior and secretes protective chemicals HCL and protein digesting enzymes to kill microorganisms from the stomach acidity pH 3 5 of the skin to inhibit bacteria growth saliva and lacrimal fluids containing lysozymes kill bacteria and mucus to trap microorganisms trying to enter 4 Explain Nonspecific Cellular Chemical Defense the second line of defense including phagocytes phagocytosis phagocyte mobilization and other factors in this line This is the second line of defense When a substance does get past the skin or mucus membranes our body depends on this to kill pathogens and repair tissue First we have the phagogcytes 2 types that engulf and confront pathogens Macrophages are cells that search throughout the body leaving the bloodstream for foreign substances and destroy them by engulfing them We also have the neutrophils are one of the WBC s that attack pathogens upon an encounter and when is needed Phagocytosis the phagocyte attaches to the pathogen microbe engulfs it via endocytosis plasma extensions bind by forming a membrane lined vacuole around it or pulling into it now called a phagosome Phagosome will fuse with a lysosome contains strong digestive enzymes to form a phagolysosome Then the microbe is killed and digested by lysosome enzymes leaving a residual body to be removed by exocytosis Tony Berardi As you see first the phagocyte has to bind to the pathogen so it needs help either with complimentary proteins or a vaccine will help o Lysosome is one way to destroy the pathogen others are via o Respiratory burst which is using free radicals to kill the pathogen o Our cells can cause potassium K to enter the phagosome cell which this will raise the pH and activate certain proteins to finish the job o This is how macrophages work neutrophils simply secrete defensins that kill the pathogen by piercing the pathogen membrane Neutrophils are housed in the bone marrow so they will leave into the blood stream when needed called o Neutrophils are mobilized in a certain way Leukocytosis Margination diapedesis leukocytosis and chemotaxis Leukocytosis Neutrophils are housed in the bone marrow so they will leave into the blood stream when needed Margination is when the neutrophil clings to the inner capillary wall They cling to something called cell adhesion molecules or CAM s Diapedesis Then it will flatten and squeeze across the capillary diapedesis Chemotaxis Then phagocytes will be attracted by all the inflammatory chemicals that the injured site of the cell release Now for the natural killer cells These are defense cells in the blood and lymph that kill infected cells in the body Since the adaptive immune system takes a while to take action these cells will kill infected cells also cancer as it can BEFORE the adaptive immune system is activated They attack based on if they cannot recognize certain cell surface receptors that all body cells have if these cell surface receptors are lacking the cell is foreign Pathogens also have certain sugars on them that the NK cells will recognize The NK cells non phagocytic will secrete chemicals to enhance the inflammatory response they might also simply activate apoptosis in the infected cell killing it o Inflammatory response is triggered when the tissues are injured Tony Berardi 1 Prevents the spread of damaging agents to nearby tissues 2 Dispose of cell debris and pathogens 3 Sets repair stages o There are four cardinal signs redness heat swelling and pain these may hinder joint movement 5 Describe the responses to injury reactive hyperemia and the mechanisms of occlusion training Say you cut your finger or get an injury what happens The inflammatory response occurs This is a response to certain chemicals cytokines that an injured cell or tissue release All of these will help in healing When injured the injury site will release histamine mast cells prostaglandins cytokines attract WBC which will vasodilate small vessels in the injured area to cause more blood to rush to the site This will also make the cell more permeable for fluid to leak out the chemicals will also attract the macrophages and neutrophils to the site the process to attract something in the body is called chemotaxis The brain will perceive these chemicals as pain The vasodilation will increase the blood flow to the area which
View Full Document
Unlocking...