Lymphatic and Immunity System

1. Lymphatic and Immunity System Idalis Laboy Alec Wilkins

2. The Lymphatic System • The lymphatic system, like the cardiovascular system, includes a network of vessels that transport fluids. The Lymphatic System has two jobs: 1. To carry away excess fluids from interstitial spaces in tissues and to return it to the blood stream. 2. To protect the body against pathogens or viruses.

3. Lymphatic Pathways

4. Lymph Capillaries Are closed ended tubes that begin in the interstitial spaces of most tissues. The walls of lymphatic capillaries make it possible for tissue fluid to enter lymphatic capillaries. The fluid inside lymphatic capillaries is called lymph.

5. Lymphatic Pathways • Lymphatic vessels: these vessels are similar to veins but are much thinner in size. These eventually lead to Lymph Nodes and after will sometimes leave to flow into larger Lymph Trunks. • Lymphatic Nodes: The larger lymphatic vessels lead to specialized organs called lymph nodes. • Lymphatic trunks: drain lymph, are named for the regions they serve. They join one of two collecting ducts, the thoracic duct or the right lymphatic duct. • http://www.youtube.com/watch?v=Kh-XdNnTZUo

6. Tissue Fluid Formation Lymph Formation and Function • Filtration from the plasma normally exceeds re absorption, leading to the net formation of tissue fluid. • This increases the interstitial fluid hydrostatic pressure somewhat, favoring movement of tissue fluid into lymphatic capillaries, forming lymph. • Lymph returns to the bloodstream most of the small proteins that leak out of the blood capillaries. • At the same time, lymph transports foreign particles, such as bacteria or viruses, to lymph nodes. Tissue fluid originates from blood plasma and is composed of water and dissolved substances that leave blood capillaries. Capillary blood pressure causes filtration of water and small molecules from the plasma.

7. Lymph Nodes and Locations Lymph Nodes are distributed all throughout the body and are made up of many different chambers.

8. Lymph Nodes • Two primary functions: 1. Filtering potentially harmful particles from lymph before returning it to the bloodstream. 2. Immune surveillance, provided by lymphocytes ad macrophanges. • Lymphocytes attack invading viruses, bacteria, and other parasitic cells that lymphatic vessels bring to the nodes. • Macrophanges in the nodes engulf and destroy foreign substances, damaged cells, and cellular debris.

9. Major Organs involved Thymus Spleen • The thymus secretes the hormone thymosin, which influences the maturation of T cells once they leave the thymus and provide immunity. • The spleen is the largest lymphatic organ. • It filters the blood and removes damage blood cells and bacteria.

10. Protection through the Lymphatic System • One of the man functions of the lymphatic system is to defend against pathogens. This is done through innate defenses such as species resistance, mechanical resistance, chemical barriers, fever, inflammation and phagocytosis and adaptive defenses such as antigens, lymphocytes, T cells, B cells and antibodies.

11. Innate Defenses • Species resistance is when organisms or species develop a set of diseases that is unique to it. • Mechanical Barriers are skin an mucus membranes that line passages. These barriers prevent infectious agents from entering the body. They are the first line of defense. • Chemical Barriers are enzymes and body fluid that fights and locates infectious agents in the body. • Fever is an elevated body temperature that lowers iron throughout the body. The essentially starves bacteria.

12. Innate Defenses Cont. • Inflammation is a tissue response to injury or infection. The swelling and heating of the site allows infection to be walled into a specific area. • Phagocytosis is the process of removing foreign particles through lymph as it passes through the blood stream.

13. Adaptive Defenses, or Immunity • The body’s third line of defense, immunity refers to the response mounted by the body against specific, recognized foreign molecules. • Antigens: A chemical that stimulates B lymphocytes to produce antibodies • Lymphocytes: A type of white blood cell that provides immunity. • T Cells: Lymphocyte that interacts directly with antigens and produces cellular immunity response. • B Cells: Lymphocyte that secrets antibodies that bind and destroy foreign substances.

14. T and B cells activation

15. Types of Antibodies • Immunoglobulin G: defends against bacterial cells, viruses, and toxins and activates complement. • Immunoglobulin A: defends against bacteria and viruses. • Immunoglobulin M: activates complement and reacts with blood cells during transfusions. • Immunoglobulin E: is found in exocrine gland secretions and promotes allergic reactions. • Immunoglobulin D: is found on the surface of most B lymphocytes and functions in B cell activation.

16. Immune Responses • Primary immune response: When B or T cells become activated the first time, after which some cells remain as memory cells. • Secondary immune response: If the same antigen is encountered again, numerous memory cells can mount a more rapid response.

17. Types of Immunity • Active Immunity: Results when a person produces an immune response. This is long lasting • Passive Immunity: When a person receives antibodies produced by another individual. This is short term. • Naturally Acquired Immunity: When a person exposed to a pathogen develops a disease. • Artificially Acquired Immunity: When a person receives a vaccine which is a bacteria is weakened or killed, and produces mild symptoms but still a primary immune response.

18. Immune System Errors Allergic Reactions Tissue Rejection • An allergic response is an immune attack against a non-harmful substance. This is really an overreaction to a foreign substance that may cause tissue damage. • When one person receives an organ from another individual, the immune system may recognize the donor’s organ as a foreign substance and attempt to destroy it.

19. Autoimmunity • Auto antibodies • AutoimmunityT cells that attack and damage the body’s tissues and organs. • In autoimmune disorders, the immune system manufactures antibodies against some of its own antigens. • Autoimmune disorders may result from viral infection, faulty T cell development, or reaction to a non self antigen that bears close resemblance to a self antigen.

20. Diseases • Lymphedema is a chronic swelling of the limbs caused by the accumulation of lymph fluid that occurs if the lymphatic system is damaged or not functioning properly. While the limbs are typically involved, the face, neck and abdomen may also be affected. • HIV infection gradually shuts down the immune system. • Elephantiasis  is a rare disorder of the lymphatic system. This is when there is an abnormal accumulation of watery fluid in tissues, causing severe swelling.

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