Chapter 14 Lymphatic System and Immunity

1. Chapter 14Lymphatic System and Immunity • Lymph system is made up of 3 parts • Lymph • Lymph vessels • Lymphatic tissue

2. Chapter 14Lymphatic System and Immunity • Lymph system is made up of 3 parts • Lymph • The name for tissue fluid that enters lymph capillaries • Lymph vessels • Lymphatic tissue

3. Chapter 14Lymphatic System and Immunity • Lymph system is made up of 3 parts • Lymph • Lymph vessels • A system of dead-end vessels that begin as lymph capillaries found in most tissue spaces. • Lymphatic tissue

4. Chapter 14Lymphatic System and Immunity • Lymph system is made up of 3 parts • Lymph • Lymph vessels • Lymphatic tissue • Lymph Nodes – usually larger 10 to 20 mm in length • Lymph nodules – usually smaller <1 mm to 3 mm in length • Spleen – located in ULQ of abdominal cavity • Thymus – located inferiorly to the thyroid gland

5. Lymphatic System • Lymph • Another name for fluid in the body • Eventually returned directly to the circulatory system via the subclavian veins

7. Lymphatic System • Lymph Vessels • Begin as lymph capillaries, which are very permeable • Lacteals are specialized lymph capillaries found in the small intestine – they absorb the fat-soluble end products of digestion; fatty acids and vitamins A, D, E, and K • Lymph Capillaries unite to form lymph vessels • Lymph vessels are structurally like the veins of the circulatory system • One way valves to prevent backflow • Smooth muscle constricts to move fluid along • No pump for lymph (as heart for the circulatory system) • Skeletal muscle pump, as in the muscles of the legs and arms • Respiratory pump alternately expands and compresses the lymph vessels in the chest

8. Lymphatic System • Lymph Vessels • Where is the lymph going? • The lymph vessels of the lower body unite in front of the lumbar vertebrae to form a vessel called the cisternachyli, which continues upward in front of the backbone as the thoracic duct. • Lymph vessels from the ULQ of the body join the thoracic duct which empties into the left subclavian vein. • Lymph vessels from the URQ unite to form the right lymphatic duct, which empties into the right subclavian vein

10. Lymphatic System • Lymphatic Tissue • Lymph Nodes • Found in groups along the pathways of the lymph vessels • As lymph passes through a node , bacteria and other foreign materials are phagocytized by fixed macrophages • Plasma cells develop from lymphocytes exposed to pathogens in the lymph and produce antibodies • 3 paired groups with strategic locations Cervical, Axillary, and Inguinal lymph nodes • Lymph Nodules • Spleen • Thymus

11. Lymphatic System • Lymphatic Tissue • Lymph Nodes • Lymph Nodules – small masses of lymphatic tissue found just beneath the epithelium of all mucous membranes • Respiratory, digestive, urinary, and reproductive • Lymph nodules with specific names • Peyer’s patches – small intestines • Tonsils – pharynx • Spleen • Thymus

13. Lymphatic System • Lymphatic Tissue • Lymph Nodes • Lymph Nodules • Spleen – Located in ULQ of abdominal cavity • In fetus spleen produces RBCs, after birth this is done by red bone marrow • After birth the spleen functions like a large lymph node except its functions affect the blood instead of lymph • The functions of the Spleen are: • Contains plasma cells that produce antibodies to foreign antigens • Contains fixed macrophages that phagocytize pathogens, foreign materials, and old red blood cells to form bilirubin • Stores platelets and destroys them when they are no longer useful • Thymus

14. Lymphatic System • Lymphatic Tissue • Lymph Nodes • Lymph Nodules • Spleen • Thymus – located inferiorly to the thyroid gland • Large in fetus and infant – extends under sternum • Decreases in size with age – very little thymus tissue found in adults • Produce T lymphocytes, or T cells • Thymic hormones enable the T cells to participate in the recognition of foreign antigens and to provide immunity

15. Immunity • Immunity – The ability to destroy pathogens or other foreign material and to prevent further cases of certain infectious diseases • Immunity has two main components: • Innate immunity • Adaptive Immunity

16. Immunity • Innate immunity • Nonspecific • Does not create memory • Responses are the same regardless of target • Adaptive Immunity

17. Immunity • Innate immunity • Adaptive Immunity • Very specific as to its target • May involve antibodies • Does create memory • May become more efficient

18. Immunity • Innate immunity • Barriers • Stratum Corneum of the epidermis • Fatty Acids in sebum • Mucus of the Ciliated epithelium in upper respiratory tract • Hydrochloric acid in digestive tract • Lysozyme in saliva and tears • Defensive cells • Chemical Defenses

19. Immunity • Innate immunity • Barriers • Defensive cells • WBCs in the form of fixed and wandering Macrophages • Neutrophils and eosinophils are capable of phagocytosis • Langerhans cells in the skin • Natural Killer cells circulating in the blood stream, red bone marrow, spleen , and lymph nodes • Basophils and mast cells – part of inflammation response • Chemical Defenses

20. Immunity • Innate immunity • Barriers • Defensive cells • Chemical Defenses • Interferons – block the reproduction of viruses • Complement – 20 or more Plasma Proteins that circulate in the blood stream • Inflammation – try to contain damage, keep it from spreading, eliminate the cause, and permit repair to take place

22. Immunity • Adaptive Immunity • Cell-Mediated • Does not produce antibodies • Effective against intercellular pathogens – viruses, fungi, malignant cells and grafts of foreign tissue • Activated T cells – Memory T cells and cytotoxic (killer) T cells • Antibody-Mediated

23. Immunity • Adaptive Immunity • Cell-Mediated • Antibody-Mediated • Does produce antibodies • Production of activated B cells • B Cells produce plasma cells which produce antibodies specific for this foreign antigen • Antibodies – immune globulins (Ig) or gamma globulins • Specialized proteins that attach to specific antigens forming an antigen-antibody complex which results in opsonization • Opsonization is the labeling for phagocytosis by macropages or neutrophils

25. Immunity • Antibody Responses • First exposure to foreign antigens does stimulate antibody production, but slowly and in small numbers • On first exposure antibody production is usually too slow to prevent the disease itself. • A second exposure initiates a rapid and large production of antibodies • Allergies are a result of this Antibody response

27. Immunity • Types of Immunity • Genetic Immunity • Does not involve antibodies, or barriers • Few pathogens can cross species – i.e. from dogs to humans • With Genetic immunity can also come genetic vulnerability • Acquired Immunity

28. Immunity • Types of Immunity • Genetic Immunity • Acquired Immunity • Does involve antibodies • Two categories • Passive immunity - Antibodies are from another source • Natural - Placental transmission of antibodies – which can be prolonged by breast-feeding • Artificial – injection of preformed antibodies (gamma globulins) German measles, tetanus, hep A & B, • Active immunity

29. Immunity • Types of Immunity • Genetic Immunity • Acquired Immunity • Does involve antibodies • Two categories • Passive immunity • Active immunity - Individual produces their own antibodies (adaptive Immunity) • Natural- recovery from a disease with production of antibodies • Artificial – vaccine stimulates production of antibodies and memory cells