Lecture 3 Tuesday September 11 2012 Lymphatic and Immune Systems Slide 1 the Lymphatic and Immune Systems Slide 2 The Lymphatic System Consists of two parts o Lymphatic vessels o Lymphoid tissues and organs Lymphatic System functions o Transport escaped fluids back into blood o Plays essential roles in body defense and resistance to disease o Also has a role indigestion Fluid out of capillaries interstitial fluid filtered at the lymph nodes returned to heart No pump moved by motion Slide 3 Developmental Aspects of the Lymphatic System and Body Defenses Except for thymus and spleen the lymphoid organs are poorly developed before birth A newborn has no functioning lymphocytes at birth only passive immunity from the mother o Not a good immune system because he is relying on If lymphatics are removed or lost severe edema results but vessels may grow back in time Slide 4 Central Lymphoid Tissue Bone Marrow Thymus Central Lymphoid Tissue Bone Marrow o Hematopoictic stem cells precursor for all blood cells o Leukocytes except T lymphocytes fully developed here Thymus o T lymphocytes migrate from bone marrow to thymus o Develop maturity in thymus Slide 5 Peripheral Lymphoid Tissue Spleen lymph nodes tonsils adenoid appenxid Peyer s patches Collections of B cells T cells and macrophages Function to trap microorganisms and foreign particles Works to expose them to leukocytes in high BLANK Spleen and lymph nodes filter blood and lymph Slide 6 Lymphoid Organs the contribute to Lymphatic Function Spleen o Located on the left side of the abdomen o Filters blood and destroys worn out blood cells o Forms blood cells in the fetus o Acts as blood reservoir Thymus o Located low in throat overlying the heart o Functions at peak levels only during childhood o Produces hormones like thymosin to program lymphocytes Tonsils o Masses of lymphoid tissue around the pharynx o Trap and remove bacteria and other foreign materials o Tonsillitis is caused by congestion with bacteria o Destorys pathogens you inhale or eat Peyer s patches o Found in the wall of the small intestine and capture and destroy bacteria in the intestine o In the GI track o Function the same as tonsils Slide 7 Lymph Nodes Filters lymph fluid before it is retuned to the blood o Excess interstitial fluid that has seeped out Defense cells within lymph nodes o Macrophages engulf and destroy foreign substances o Lymphocytes provide immune response to antigens Some harmful materials that may enter lymph vessels o Bacteria o Viruses o Cancer cells o Cell debris o Protists o Worms o Fungi Epitope region the body attacks Slide 8 Lymph Node Structure Most are kidney shaped and less than 1 inch long Cortex o The outer part o Contains follicles that house collections of lymphocytes Medulla o The inner part o Contains phagocytic marcophages Afferent to Afferent more than efferent because as the interstitial fluid is getting Efferent away Sinus cavity filtered it gets held up in the lymph nodes where it comes in contact with the lymphocyes and then gets filtered Slide 9 Lymphatic Characteristics Lymph fluid carried by lymphatic vessesl Properties of lymphatic vessels o One way system toward the heart o No pump o Lymph moves towards the heart Squeezing motion toward the heart Rhythmic contraction of smoot muscle in vessel walls Elephantiasis Filariasis o Caused by mosquitos that transmit parasitic worms o Worms end up in lymphatic system and use nutrients to grow and reproduce o Amputation or can kill the worms gradually Slide 10 Filariasis Cycle Diagram See Diagram Parasites coevolution Good CV health good immune system fucntion Slide 11 The Flow of Lymph through the Nodes Lymphatic Vessels Lymph centers the convex side through afferent lymphatic vessels Lymph flows through a number of sinuses inside the node Lymph exits through efferent lymphatic vessels Fewer efferent than afferent vessels causes flow to be slowed Slide 12 Lymphatic Vessels Lymph capillaries o Walls overlap to form flap like minivalves o Fluid leaks into lymph capillaries o Capillaries are anchored to connective tissue by filaments o Higher pressure on the inside closes minivalves o Fluid is forced along the vessel Slide 13 Lymphatic Vessels Lymphatic collecting vessels o Collected lymph form lymph capillaries o Carry lymph to and away from lymph nodes o Return fluid to circulatory veins near the heart Right lymphatic duct Thoracic duct Slide 14 The Immune System Slide 15 Body Defenses The Immune System The body is constantly in contact with protists bacteria fungi and viruses The body has two defense systems for foreign materials o 1 Innate defense system nonspecific defense system Mechanisms protect against a variety of invaders Responds immediately to protect body from foreign materials o 2 Adaptive defense system specific defense system is specific defense is required for each type of invader We can develop immunity or specific resistance to certain pathogens See Diagram o Innate Non specific First line of defense preventing entrance of pathogens Skin Mucous membranes Secretions of skin and mucous membranes Second line of defense now that they ve entered tries to get rid of pathogens o Adaptive specific Third line of defense identify pathogens and strategize Phagocytic cells Antimicrobial proteins The inflammatory response Lymphocytes Antibodies Macrophages Slide 16 Innate Non Specific Body Defenses First Line of Defense Physical Barriers o Skin is a physical barrier to foreign materials o Mucous membranes o Mucus traps microorganisms in digestive and respiratory pathways Particles get trapped in mucous then pushed out by cilia Chemical barriers toxic to bacteria o Secretions from sebaceous and sweat glands salty sweaty sebum is Skin is salty and acidic inhibits growth of pathogens and has an acid mantle o Sebaceous glands excrete oily substance into hair follicles o Urine o Vaginal secretions are acidic o pH of the skin is acidic to inhibit bacterial growth o Stomach mucosa and secretes hydrochloric acid also has protein digesting enzymes o Lysozyme in tears sweat saliva ect can break down bacteria Slide 17 Innate Nonspecific Body Defenses First Line of Defense See Diagram Explains previous slide Slide 18 Nonspecific Immune System s General Response Flu like Symptoms These are just a generic response when pathogens enter the body Fever o Explained on next slide Runny nose watery eyes o Oozing out to remove the pathogen Fluid and mucus in lungs o Oozing out to remove the
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