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 separate systems but they depend on each other The first system is the innate immune system This system contains the first two lines of defense the external membranes skin etc and the inflammatory system macrophages etc Both of these lines act within minutes of a threat The second system is the adaptive immune system The third line of defense is here This system with the T and B cells is very specific to a certain virus bacteria This system takes 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 days to get into action 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 substances some go to alert cells in the adaptive system to work So it is telling the adaptive system to get ready that a foreign substance is in the body 1 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 and second from many foreign substances The mucus membranes lining our stomach and other organs also secrete chemicals to kill bacteria and toxins The skin is strong because of a protein called keratin this serves as a barrier to outside substances weak acids and pollution acidity to kill harmful substances The mucous membranes line most organs and secrete chemicals such as HCl with its high 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 First we have the phagogcytes that engulf pathogens Macrophages are cells that search throughout the body for foreign substances and destroy We also have the neutrophils which if you recall from anatomy 1 are one of the WBC s that them by engulfing them attack pathogens The macrophages attaches to the pathogen engulfs it via endocytosis by forming a vacuole around it called a phagosome this will fuse with a lysosome Lysosomes are very acidic inside and this will digest the pathogen Then the remains are spit out of the macrophage Lysosome is one way to destroy the pathogen others are via respiratory burst which is using free radicals to kill the pathogen or our cells can cause potassium to enter the phagosome cell which this will raise the pH and activate certain proteins to finish the job This is how macrophages work neutrophils simply secrete defensins that kill the pathogen Neutrophils are housed in the bone marrow so they will leave into the blood stream when needed called leukocytosis Neutrophils are mobilized in a certain way Margination diapedesis and chemotaxis 2 Margination is when the neutrophil clings to the capillary wall They cling to something called cell adhesion molecules or CAM s Then it will flatten and squeeze across the capillary This is called diapedesis Then it will be attracted by all the chemicals that the injured site of the cell release more on the next question This is chemotaxis 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 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 as it can They attack based on if they cannot recognize certain receptors that all body cells have if these receptors are lacking the cell is foreign Pathogens also have certain sugars on them that the NK cells will recognize The NK cells will enhance the inflammatory response which is explained next They might also simply activate apoptosis in the infected cell killing it 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 that an injured cell or tissue release All of these will help in healing When injured the injury site will release histamine prostaglandins cytokines which will vasodilate 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 will increase the redness of the area called reactive hyperemia The increased blood flow will cause more oxygen to travel to the area and facilitate debris to leave the area dead cells etc The heat from the increased blood flow will also increase the metabolism of the cells in the injury site 3 The increased permeability of the capillaries will cause fluid to leak into the interstitial space which we will perceive as pain This will cause limited mobility of the joint But platelets will also leak out which will help in healing This is called the inflammatory response and happens when injured It is noted by redness in the injury site heat swelling and of course pain Breaking done muscles when working out actually initiates this to give you an idea of why your muscles hurt after lifting Now for occlusion training and what the point of it is This is when you cut off blood flow to a muscle During resistance training by occluding a muscles you sever the oxygen supply to it so it tires out much quicker What is the point to this This will make the muscle reach failure much quicker and at a light load making it possible to break the muscle down to a greater extent The lack of blood flow will recruit the fast twitch muscle fibers much quicker which are the fibers that we
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