Lymphatic System Where s your immunity idol?
Functions of the Lymphatic System Fluid Balance Drains excess fluid from tissues Lymph contains solutes from plasma Fat Absorption Lymphatic system absorbs fat from digestive system through lacteals Defense Lymph nodes help filter microorganisms from the body
Structure of Lymphatic Tissue
Lymphatic Vessels Capillaries more permeable than blood capillaries Have one way valves preventing lymph from passing back into the tissues Contraction of lymphatic vessels, skeletal muscle, and thoracic pressure changes move lymph through the vessels
Lymphatic Trunks Lymphatic vessels pass through lymph nodes then converge to lymphatic trunks Jugular Trunks drain head and neck Subclavian Trunks drain upper limbs, superficial thoracic wall and mammary glands Bronchomediastinal Trunks thoracic organs Intestinal Trunks abdominal organs Lumbar Trunks lower limbs, pelvic organs, reproductive organs, kidneys and adrenal glands
Lymphatic Ducts Lymphatic Trunks connect to lymphatic ducts or large veins Right lymphatic duct 20% people jugular, subclavian, bronchomediastinal trunks Thoracic duct drains lymph from right side of body inferior to thorax and entire left side of the body
Lymphatic Ducts
Structure of Lymphatic Tissue Contains reticular cells that make reticular fibers Contains lymphocytes (B and T cells) for immune response 2 types Encapsulated surrounded by connective tissue MALT mucosa associated lymphoid tissue nonencapsulated lymphatic tissue found under mucous membranes MALT include diffuse lymphatic tissue, lymphatic nodules, tonsils
Diffuse Lymphatic Tissue No clear boundary; found around lymphatic nodules and within lymph nodes and spleen Contains lymphocytes, macrophages and other cells Lymphatic Nodules Spherical dense aggregates of lymphoid tissue Plentiful in digestive, urinary, respiratory, and reproductive systems Peyer s patches lymphatic nodules of the distil small intestines and appendix Lymphatic follicles nodules found in the spleen or in lymph nodes
Tonsils Groups of lymphatic nodules and diffuse lymphatic tissue 3 groups of tonsils Palatine large oval shaped at oral cavity and pharynx junction Pharyngeal lymphatic nodule collection near nasal cavity and pharynx join Lingual lymphatic nodules on the posterior surface of the tongue
Lymph Nodes Scattered along lymphatic vessels Filter bacteria or other material from the lymph 2 categories: superficial and deep
Spleen White pulp lymphatic tissue surrounding arteries Red pulp lymphatic tissue associated with veins Destroys defective RBCs Detects and responds to foreign materials Blood reservoir
Thymus Decreases in size in late life Divided into irregular shaped lobules filled with lymphocytes (cortex) The medulla is composed of thymic corpuscles rounded epithelial structures Lymphocyte production and T-cell maturation
Immunity Ability to resist damage from foreign substances, harmful chemicals, and internal threats 2 categories Innate immunity or nonspecific resistance Body recognizes and destroys antigens response is always the same Adaptive immunity Specificity recognizes and distinguishes between specific bacteria Memory it remembers previous encounters Faster and sharper response
Innate Immunity Mechanical Mechanisms Prevent entry into the body or remove antigens from body surfaces Skin Mucous membranes Tears Saliva Urine Coughing Sneezing Ciliated tissues
Innate Immunity Chemical Mediators Found on cell surfaces to kill or prevent microorganism entry Promote inflammation Cytokines are secreted by cells to bind to cell surface receptors to regulate intensity and duration of immune response and stimulate the production of different cell types Examples: interferons, interleukins, lymphokines
Innate Immunity Chemical Mediators Complement Group of 20 proteins C1-C9 and factors B,D, and P Circulate in inactive form, activation = the complement cascade 2 ways to begin complement cascade Alternative pathway C3 becomes active spontaneously Classical pathway
Innate Immunity Chemical Mediators Complement Activated complement produces a membrane attack complex (MAC) Na+ and water flood into the cell to cause lysis In some bacteria lysozyme enters and digests the cell wall Complement can attach to bacteria surfaces to stimulate macrophages Complement attracts WBCs and promotes inflammation
Innate Immunity Chemical Mediators Interferons Proteins produced by viral infected cells that attach to neighboring cell surfaces stimulating the cells to produce antiviral proteins
Cells of the Immune System Neutrophils small phagocytic, first to infected areas, release lysosomal enzymes Macrophages enlarged monocytes in the tissues Clean up neutrophils in late infection Produce interferons, prostaglandins, and complement
Cells of the Immune System Natural Killer (NK) Cells Recognize tumor cells or virus infected cells release chemicals to cause cells to lyse Basophils motile WBC Mast Cells nonmotile WBC in connective tissue Eosinophils clean up histamine and leukotrienes from basophils
Inflammatory Response Tissue damage occurs releasing or activating chemical mediators Vasodilation occurs Chemotactic attraction of phagocytes Increased vascular permeability Neutrophils and macrophages clean area tissue repaired
Inflammatory Response Local inflammation confined to a specific area Symptoms: redness, heat, swelling, pain Systemic inflammation occurs in many parts of the body Symptoms: local symptoms, large amounts of neutrophils produced, fever, increased vasodilation
Adaptive Immunity Antigens substances stimulating adaptive immunity responses foreign and self antigens Antibody-Mediated Immunity involves B- cells making antibodies Cell-Mediated Immunity involves T-cells Effector T-cells cytotoxic T-cells and delayed hypersensitivity T-cells Regulatory T-cells helper T-cells and suppressor T-cells
Lymphocyte Activation Antigenic Determinants or Epitopes Specific regions of antigens that are recognized by lymphocyte receptors
Lymphocyte Activation Major Histocompatability Complex Molecules MHC Class I Molecules Display antigens on its surface produced by the cell MHC Class I/antigen complex combine with T-Cells T-Cells destroy the infected cell MHC Class II Molecules Found on antigen presenting cells = B-cells, macrophages, monocytes, dendritic cells Combine with fragments of broken down antigens and displays them on the surface of the cell T-cells bind to the MHC Class II/antigen complex causes an alert signal to the immune system Antibodies are produced
Lymphocyte Activation Costimulation Cytokines released from cells help stimulate the immune system T4 cells have a glycoprotein CD4 T8 cells have a glycoprotein CD8
Lymphocyte Activation Lymphocyte proliferation Helper T-Cells increase in number Effector T or B cells increase in number
T Cell Production
B Cell Production
Inhibition of Lymphocytes Tolerance lymphocyte is unresponsive to an antigen 3 ways to induce tolerance Deletion of Self Reactive Lymphocytes Prevention of Lymphocyte Activation Activation of Suppressor T-Cells
Antibody Mediated Immunity Antibody Structure Globulin proteins immunoglobulins (Ig) or gamma globulins Five classes IgG, IgM, IgA, IgE, IgD Consists of 4 protein chains 2 light and 2 heavy Each has a variable region for specific antigens and a constant region
Antibody Mediated Immunity Effects of Antibodies Antibodies directly attach to antigens Antibodies attach to antigens and the complement cascade is started by the constant region of the antibody Opsonins make antigens more susceptible to phagocytosis
Antibody Production Primary Response 1 st exposure of a B-cell to an antigen; results in cell differentiation and antibody production; 3-14 day response time B-cell has IgM and IgD antibodies as antigen receptors Once stimulated, B-cell divides to form plasma cells and memory B cells
Antibody Production Secondary or Memory Response 2 nd exposure to an antigen; results in memory B cells dividing to produce plasma cells which make antibodies in large quantities; response time is hours to days Each exposure causes memory B cells to be produced Memory B cells can provide a defense for years to life
Cell Mediated Immunity Effective against intracellular microorganisms A virus infected cell displays viral proteins complexed to MHC I T cells recognize and activate Helper T cell costimulate the cytotoxic T cell T cells divide to create cytotoxic T cells and memory T cells
Cytotoxic T cells Cell Mediated Immunity Lyse cells by using perforin Release cytokines to stimulate other immune response Delayed Hypersensitivity T Cells Produce cytokines to promote inflammation and phagocytosis
Acquired Immunity Active Natural Active Artificial Passive Natural Passive Artificial
Cell Mediated Immunity