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Johny's A&P lymphatic and immunological system

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immunology and lymph

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Johny's A&P lymphatic and immunological system

  1. 1. Mr. Johny Kutty Joseph Asstt. Professor SMVDCoN
  2. 2.  Lymph is the fluid that circulates throughout the lymphatic system. The lymph is formed when the interstitial fluid is collected through lymph capillaries.  It is then transported through larger lymphatic vessels to lymph nodes, where it is cleaned by lymphocytes, before emptying ultimately into the right or the left subclavian vein, where it mixes back with the blood.  It is generally similar to blood plasma except that it also contains white blood cells and some proteins.  Lymph may pick up bacteria and bring them to lymph nodes, where they are destroyed.  Lymph also transports fats from the digestive system to the blood.  the lymph formed in the human digestive system called
  3. 3.  Blood supplies nutrients and important metabolites to the cells of a tissue and collects back the waste products they produce, which requires exchange of respective constituents between the blood and tissue cells.  This exchange is not direct, but instead is effected through an intermediary called interstitial fluid.  IDF is formed at capillary network and some plasma leak out from arterial capillary end due to higher pressure. This leaked out fluid is called lymph.  Lymph when formed is a watery clear liquid with the same composition as the interstitial fluid.  It flows through the lymph nodes it comes in contact with blood, and tends to accumulate more cells
  4. 4.  Lymph nodes of the head are Occipital lymph nodes, Mastoid lymph nodes and Parotid lymph nodes.  Lymph nodes of the neck are Cervical lymph nodes, Deep cervical lymph nodes, Inferior deep cervical lymph nodes and Supraclavicular lymph nodes  Lymph nodes of the lungs: are subsegmental, segmental, lobar and interlobar lymph nodes.  Mediastinal lymph nodes: They consist of several lymph node groups, especially along the trachea, esophagus and the diaphragm.  In the mediastinal lymph nodes arises lymphatic ducts, which drains the lymph to the left subclavian vein.  Lymph nodes of the arm; These drain the whole of the arm, and are divided into two groups, superficial and deep.  Lower limbs have Superficial inguinal lymph nodes, Deep
  5. 5.  Tubular vessels transport lymph back to the blood, ultimately replacing the volume lost during the formation of the interstitial fluid. These channels are the lymphatic channels, or simply lymphatics.  Unlike the cardiovascular system, the lymphatic system is not closed and has no central pump, or lymph hearts.  Lymph transport is slow and sporadic. Despite low pressure, lymph movement occurs due to peristalsis , valves, and compression during contraction of adjacent skeletal muscle and arterial pulsation.  Lymph that enters the lymph vessels from the interstitial space usually does not flow backwards along the vessels because of the presence of valves.  If excessive hydrostatic pressure develops within the lymph vessels, though, some fluid can leak back into the interstitial space and contribute to formation of oedema.
  6. 6.  Water and solutes continually filter out from capillary into interstitial space.  To balance this outflow fluid continually reenters blood through lymphatic system.  Fluid that is forced out of the bloodstream during normal circulation is filtered through lymph nodes to remove bacteria, abnormal cells and other matter.  This fluid is then transported back into the bloodstream via the lymph vessels.  Lymph only moves in one direction, toward the heart.
  7. 7.  The immune system is a host defense system comprising many biological structures and processes within an organism that protects against disease.  In humans, the blood–brain barrier, blood– cerebrospinal fluid barrier, and similar fluid–brain barriers separate the peripheral immune system from the neuroimmune system which protects the brain.
  8. 8.  T cells (thymus cells) and B cells (bone marrow derived cells) are the major cellular components of the adaptive immune response.  The function of T cells and B cells is to recognize specific “non-self” antigens, during a process known as antigen presentation.  Once they have identified an invader, the cells generate specific responses that are tailored to maximally eliminate specific pathogens or pathogen-infected cells.  B cells respond to pathogens by producing large quantities of antibodies which then neutralize foreign objects like bacteria and viruses.  Some T cells, called T helper cells, produce cytokines that direct the immune response, while other T cells, called cytotoxic T cells, produce toxic granules that
  9. 9.  Following activation, B cells and T cells leave a lasting legacy of the antigens they have encountered, in the form of memory cells which will “remember” each specific pathogen encountered, and are able to mount a strong and rapid response if the pathogen is detected again.  The formation of these cells takes place through haematopoiesis.  The formation of lymphocytes is known as lymphopoiesis. B cells mature into B lymphocytes in the bursa equivalent (bome marrow equivalent), which in humans is the the Peyer's patches of the intestine, while T cells migrate to and mature in a distinct organ, called the thymus.  Following maturation, the lymphocytes enter the circulation and peripheral lymphoid organs (e.g. the spleen and lymph nodes) where they survey for invading
  10. 10.  Immunity or resistance is the ability to ward off damage or diseases through our defence. The different types of immunity are  Innate immunity.  Adaptive immunity: Two types. a. Cell mediated immunity b. Antibody mediated immunity
  11. 11.  The innate immune system, also known as the non- specific immune system or in-born immunity system.  Innate immune systems provide immediate defence against infection.  It includes external physical/anatomical barriers and internal defences such as antimicrobial substances, natural killer cells, phagocytes, inflammation and fever.  Anatomical barrier: Skin (Sweat), Gastrointestinal tract (Peristalsis, gastric acid, bile acids, digestive enzyme, Respiratory system (mucous, surfactant, saliva) and Eyes (tears).  Anatomical barriers include physical, chemical and biological barriers.  The epithelial surfaces form a physical barrier that is
  12. 12.  Antimicrobial Substances: it include interferons (prevents viral replication), transferrin (prevents bacterial replication) etc.  Natural Killer Cells and Phagocytes: This is a form of lymphocytes which are activated by the intrusion of microorganisms. They are present lymphatic system. Phagocytes such as neutrophils and macrophages migrate to the infected area.  Inflammation:The process of acute inflammation is initiated by cells already present in all tissues, mainly resident macrophages, dendritic cells, and mastocytes. Chemical factors produced during inflammation (histamine, bradykinin, serotonin, and prostaglandins) sensitize pain receptors, cause local vasodilation of the blood vessels, and attract phagocytes, especially neutrophils.
  13. 13.  The adaptive immune system, also known as the acquired immune system or, more rarely, as the specific immune system.  Adaptive immunity creates immunological memory after an initial response to a specific pathogen, and leads to an enhanced response to subsequent encounters with that pathogen. This process of acquired immunity is the basis of vaccination.  Substances that provoke immune responses are called antigens.  Adaptive immunity includes both T-cells and B cells.  There are two types of T-cells such as helper T cells (CD4) and cytotoxic T cells (CD8). CD4
  14. 14.  Clonal Selection is the process by which a lymphocyte proliferates and differentiates in response to a specific antigen.  The clonal selection give rise to two types of cells called effecter cells and memory cells. Cell Mediated Immunity: This begins same as the clonal selection by the activation of T cells. the result of clonal selection is the formation of clone of cells that recognize the antigen as the original lymphocyte. (effectors an memory cells.) Antibody Mediated immunity: The response B cells in response to an antigen. In response to antigen the B cells undergo clonal selection forming a clone of plasma cells and memory
  15. 15.  An antigen is a molecule capable of inducing an immune response on the part of the host organism.  Exogenous antigens are antigens that have entered the body from the outside, for example by inhalation or ingestion.  Endogenous antigens are generated within normal cells as a result of normal cell metabolism, or because of viral or intracellular bacterial infection.  An auto-antigen is usually a normal protein or protein complex (sometimes DNA or RNA) that is recognized by the immune system of patients suffering from a specific autoimmune disease.
  16. 16.  An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to identify and neutralize pathogens such as bacteria and viruses.  Antibodies are secreted by B cells of the adaptive immune system, mostly by differentiated B cells called plasma cells.  Antibodies can come in different varieties known as isotypes or classes.  IgA: Found in mucosal areas, such as the gut, respiratory tract and urogenital tract, and prevents colonization by pathogens. Also
  17. 17.  IgE: Binds to allergens and triggers histamine release from mast cells and basophils, and is involved in allergy. Also protects against parasitic worms.  IgG: The only antibody capable of crossing the placenta to give passive immunity to the fetus.  IgM: Eliminates pathogens in the early stages of B cell-mediated (humoral) immunity before there is sufficient IgG.
  18. 18.  Cytokines are a broad and loose category of small proteins that are important in cell signaling.  Cytokines modulate the balance between humoral and cell-based immune responses, and they regulate the maturation, growth, and responsiveness of particular cell populations.  Each cytokine has a matching cell-surface receptor.  Cytokines are often involved in several developmental processes during embryogenesis.  Cytokines are crucial for fighting off

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