1. The Lymphatic System By Emily Lopez, Alejandro Campos, and Jennifer Leon

2. What Is the Lymphatic System?  It is the network of vessels in which lymph drains from the tissue into the blood  It is composed of lymph vessels, lymph nodes, the spleen, the thymus, tonsils, and bone marrow.

3. Functions of the Lymphatic System  The functions of this system include:  the absorption of excess fluid and its return to the blood stream  Absorption of fat (In the villi and small intestine)  Its Immune System Response

4. Lymph Vessels  Thin walled, valve structures that carry lymph  Complementary to the cardiovascular system  Lined by endothelial cells, a thin layer of smooth muscles, and adventitia(binds lymph vessels to surrounding tissue)  Types of vessels: Afferent vessels, Efferent vessels, and Lymph Trunks

5. Different types of Lymph Vessels  Afferent lymph vessels: Carries unfiltered lymph into the node  Found only in the lymph nodes  Efferent lymph vessels: Carries filtered lymph out of the node  Found in the thymus and spleen  Lymph Trunk: Carries lymph and is formed by confluence of many efferent lymph vessels

6. Different types of Lymph Vessels(Cont…)  Lymph Trunks carry lymph and then drain them into either the right lymph duct, or the thoracic duct.  There are four pairs and one unpaired lymph trunk:  Jugular Lymph Trunk  Subclavian Lymph Trunk  Bronchomediastinal Lymph Trunk  Lumbar Lymph Trunk  Intestinal Trunk(unpaired)

8. Lymph Nodes  Lymph nodes are areas of concentrated lymphocytes and macrophages along the lymphatic veins.  Located in the neck, armpit, groin, center of chest and abdomen  Act as filters for foreign particles and cancer cells  Do NOT deal with toxicity  They become inflamed or enlarged in various infections and diseases

10. The Spleen  It is a reservoir for blood  It filters the blood and lymph fluid that flows through  It sits under the rib cage in the upper left part of the abdomen towards the back

11. The Thymus  secretes hormone, thymosin, that causes pre-T-cells to mature into the T-cells

12. The Bone Marrow  contains tissue that produces lymphocytes  All lymphocytes derive from stem cells in the bone marrow

13. Absorption (and return) of Fluid  The Lymphatic System returns excess interstitial fluid(A.K.A tissue fluid) to the blood  Lymph capillaries pick up the excess interstitial fluid and proteins and return them to the venous blood  When the fluid enters the lymph capillaries it is called lymph

14. Fluid Formation  Lymph starts as Interstitial fluid  The interstitial fluid forms at the end of the arterial end of capillaries, through which hydrostatic pressure pushes outward, creating a fluid similar to plasma in terms of function. Interstitial fluid maintains equilibrium by osmotic pressure, which pushes water into the capillaries due to solubility.  90% returns to the venules. The other 10% enters the lymph capillaries making it now lymph

15. Absorption of Fat  The Lymphatic system’s second function is the absorption of fats and fat-soluble vitamins from the digestive system, and the transport of these to the venous circulation  There are lymph capillaries called lacteals in the villi of the small intestine that absorb fats and fat solubles

16. Immune System Function  Lymph nodes and other lymphatic organs filter the lymph to remove microorganisms and other foreign particles  The nonspecific responses are the first line of defense  Highly specific responses are the second line of defense and are tailored to an individual threat

17. Non-specific vs. Specific

18.  The immune response includes both specific and nonspecific components  Nonspecific responses block the entry and spread of disease-causing agents. examples: Physical Barriers(skin), Inflammation, the Complement system, and Immune Response

19. Non-specific vs. Specific(cont…)  Specific responses generate to specific invaders.  The immune system is more effective than the nonspecific methods, and has a memory component that improves response time when an invader of the same type (or species) is again encountered(antibodies)

20. Specific Cells

21. T-Cells  A.K.A “T lymphocytes”  Act as helpers to other immune cells or attack pathogens directly  After an infection, memory T cells persist in the body to provide faster reaction to the same antigen

22. B-Cells  A.K.A “B lymphocytes”  Form plasma cells to produce antibodies  These antibodies neutralize the pathogen until other immune cells destroy it

23. NK-Cells  A.K.A Natural Killer Cells  Lymphocytes that respond to a wide range of pathogens and cancerous cells

24. Non-Specific Cells

25. Macrophages  A phagocyte that consumes pathogens, destroys cells, and debris by phagocytestosis

26. Dendritic Cells  They detect pathogenic antigens which activate T and B cells to help body fight off parasites

27. Eosinophils  granular leukocytes that reduce allergic inflammation and help body fight off parasites

28. Basophils  granular leukocytes that trigger inflammation by releasing heparin and histamine

29. Neutrophils  granular leukocytes that act as the first responder to the site of infection  Neutrophils use chemotaxis to detect chemicals produced by the infection agents

30. Inflammatory Response 1. Damaged cells release histamine, a chemical messenger, that increases blood flow to the infection site 2. Inflammation produces heat; unfavorable to microbes; promotes healing; raises mobility of W. blood cells; increases metabolic rate of cells 3. Capillaries pass fluid into interstitial areas, which causes swelling 4. Clotting factors trigger blood clots 5. Monocytes clean up dead microbes, cells, and debris

31. Allergen Response  Allergies result from immune system hypersensitivity to weak antigens that do not cause an immune response in most people  Some allergens include dust, molds, pollen, certain foods and some medicines 1. After an exposure to an allergen, some people make IgE antibodies as well as B and T memory cells 2. Subsequent exposure to the same allergen releases IgE antibodies 3. IgE antibodies bind to mast cells, which then releases histamine 1. In some individuals, histamine causes life-threatening anaphylaxis

32. The Cardiovascular System vs. The Lymphatic System

33. The Cardiovascular System I. Carries oxygen throughout the body II. Flows in a continues loop III. Uses a pumping action IV. Blood is filtered by kidneys

34. The Lymphatic System I. collects and removes waste left behind in tissue II. Flows in an open circuit and only one direction III. Flows passively into the lymph capillaries by movement such as breathing, muscle movement and blood pumping IV. Invisible and difficult to detect damage V. Filtered by lymph nodes throughout the body

35. Bibliography Boundless. Cardiovascular and Lymphatic System Defenses. 1 January 2015. Webpage. 23 March 2015. Farabee, M.J. Lymphatic System and Immunity. 2001. Webpage. 23 March 2015. Knowedgebase. Lymphatic versus Cardiovascular Systems. 11 December 2013. Article. 23 March 2015.