Lymphatic System: Overview, Components, and Immunity

1. Announcements • Exams- • Extra Credit - • Lab 5 - Lymphatic System

2. Lecture Overview • Lymphatic System and Components • What is lymph and how does it travel? • General Immune Reaction- Inflammation • What is one function of the cells carried in lymph? • Selected Topics in Immunity

3. Lymphatic System • Absorbs excess fluid from the tissues • Returns this fluid to the circulatory system or the heart • Additional function in Immunity

4. Components of the Lymphatic System • Lymph • Lymphatic Tissue • Lymphatic Vessels • Thymus • Bone Marrow • Spleen

5. Lymph The clear fluid absorbed by the lymphatic system Lymphatic Tissue Clusters of Lymphocytes and macrophages Lymph

6. Lymphatic Tissue • Malt: (Mucosa Associated Lymphatic Tissue) • Diffuse array of lymphocytes found along body passages in mucous membranes. • Examples of malt: lining of the stomach and respiratory tract • Lymph nodules: • Dense clusters of Lymphocytes • Transient: pop up during infection

7. Lymphatic Vessels • Carry and Transport Lymph and proteins • Similar Structure to veins • Tunica Interna: Thin inner lining and valves • Tunica Media: Elastic fibers and Smooth Muscle • Tunica Externa: Thin Outer Layer

8. Lymphatic Filters • Lymph Nodes- Screen and FilterLymphfor infectious particles • Spleen- Screen and FilterBlood for old, dead cells and infectious particles

9. Subclavian 2 collecting Trunks 6 Lymphatic Trunks More Collecting Vessels Lymph Nodes Collecting Vessels Lymphatic Vessels

10. Lymphatic Movement • No pump • Rhythmic contraction of the lymph vessels • Skeletal Muscles • How is backflow prevented?

12. Immune Cell Generators • Bone Marrow- Makes B- Cells • Thymus- Makes T- Cells

13. Thymus

14. Break for Dynamic Human

15. Inflammation • Non-specific response to tissue trauma or infection

16. 4 signs of Inflammation

17. 4 signs of Inflammation • Redness • Swelling • Heat • Pain • What’s the purpose of pain?

18. Purpose of Inflammation • Remove Invading Pathogens • Remove Debris of Damaged Tissues • Initiate Tissue Repair

19. Mediators of Inflammation • Chemical Messengers • Leukocyte

20. Chemical Messengers • Released by mast cells in response to damage • Bradykinin, Histamine, and Leukotrienes • Increases Local Blood Flow to distressed area • Stimulates Vasodilation • Increases Permeability of Capillaries • What’s Accomplished?

21. Chemical Messengers • Bradykinin, Histamine, and Leukotrienes • Increases Local Blood Flow • Stimulates Vasodilation • Increases Permeability of Capillaries • What’s Accomplished? • Heats area causes redness and swelling • Dilutes toxins and helps Remove waste • Supplies oxygen and nutrients for tissue repair

22. Pain Response • Purpose? • Causes?

23. Pain Response • Purpose? Prevents further injury to area. • Causes? • Direct Nerve Damage • Pressure from Swelling • Chemical Stimulation particularly bradykinin

24. Leukocyte Deployment • Leukocyte: any white blood cell including T cells, B cells, granulocytes, platelets, basophils, mast cells, monocytes and macrophages • Leukocytes Migrate toward inflammed area • Why? TO KILL and RECRUIT

25. Leukocyte Deployment • Leukocytes Migrate to inflammed tissue • How? 1. Margination or pavementing: To migrate to the wall of a capillary 2. Diapedesis: Passage of blood cells through vessel wall into tissue 3. Chemotaxis: Movement of a cell towards or away a chemical source

26. What do the leukocytes plan to do? • Phagocytosis: release of toxic chemicals • Recruit more leukocytes

27. Phagocytosis • Leukocytes consume and destroy foreign invaders and dead cells • Ejected as Pus

29. Break for Dynamic Human

30. Selected Topics in Immunity