Anatomy II: Chapter 20

1. What are the two divisions of the lymphatic system?

   • Lymphatics (lymphatic vessels, lymph, lymph nodes) and lymphoid organs/tissues (spleen, tonsils, thymus, etc.)

2. What is the function of the lymphatic system?

   • Returns leaked fluids and proteins to the blood, transports fats, and plays a role in immune defense.

3. What are lymphatic capillaries?

   • Thin-walled, close-ended tubes that collect interstitial fluid.

4. What makes lymphatic capillaries highly permeable?

   • Overlapping endothelial cells forming "minivalves."

5. What are lacteals?

   • Specialized lymph capillaries in the intestines that absorb digested fats (chyle).

6. What are the two main lymphatic ducts?

   • Right lymphatic duct (drains right upper arm, right head, and thorax) and thoracic duct (drains the rest of the body).

7. Where do lymphatic ducts empty?

   • Into venous circulation at the junction of the internal jugular and subclavian veins.

8. What propels lymph through lymphatic vessels?

   • Pulsations of arteries, vessel contractions, valves, and muscular/thoracic pumps.

9. What are the two main types of lymphocytes?

   • T cells (cell-mediated immunity) and B cells (produce antibodies).

10. What do T cells do?

    • Manage immune response and attack foreign cells.

11. What do B cells do?

    • Produce plasma cells that secrete antibodies.

12. What are the main functions of lymph nodes?

    • Filtration (destroying microbes and debris) and immune system activation.

13. What are the structural regions of a lymph node?

    • Cortex (contains B cells and dendritic cells) and medulla (contains B, T, and plasma cells).

14. What is the function of the spleen?

    • Lymphocyte proliferation, immune response, blood filtration, and RBC recycling.

15. What are the two areas of the spleen?

    • White pulp (lymphocytes) and red pulp (RBC and pathogen breakdown).

16. Can a person live without a spleen?

    • Yes, but they may be more susceptible to infections.

17. What is the function of the thymus?

    • Maturation of T cells; does not directly fight antigens.

18. How does the thymus change with age?

    • It is large in infants, grows until adolescence, then gradually atrophies.

19. What does MALT stand for?

    • Mucosa-associated lymphatic tissue.

20. Where is MALT found?

    • In the tonsils, appendix, Peyer’s patches, and bronchi.

21. What is the function of the tonsils?

    • Trap and remove pathogens entering through the pharynx.

22. What are the four types of tonsils?

    • Palatine, lingual, pharyngeal (adenoids), and tubal tonsils.

23. What are Peyer’s patches?

    • Lymphoid tissue in the small intestine that destroys bacteria and generates memory cells.

24. What is the role of the appendix in immunity?

    • It contains lymphoid tissue to prevent bacterial invasion and produce memory lymphocytes.

Secondary Information:

25. What is lymph?

    • Interstitial fluid once it is picked up by lymphatic vessels.

26. What structures are considered lymphatic organs?

    • Lymph nodes, spleen, thymus, tonsils, and MALT structures.

27. Why does lymph stagnate in lymph nodes?

    • Fewer efferent vessels allow immune cells more time to act.

28. What are macrophages?

    • Cells that engulf foreign substances and help activate T cells.

29. What are dendritic cells?

    • Cells that capture antigens and present them to lymph nodes.

30. What are reticular cells?

    • Cells that form a network (stroma) supporting lymphoid organs.

31. What is the primary function of lymphoid tissue?

    • Providing a proliferation site for lymphocytes and immune surveillance.

32. Where are lymph nodes concentrated?

    • In the inguinal, axillary, and cervical regions.

33. What is the function of lymph sinuses?

    • They contain macrophages that phagocytize foreign substances.

34. What is the hilus of a lymph node?

    • The area where lymph exits via efferent vessels.

35. What is chyle?

    • Fatty lymph absorbed from the intestines.

36. What is lymphangitis?

    • Inflammation of lymphatic vessels.

37. What is lymphedema?

    • Swelling due to lymphatic obstruction.

38. What are buboes?

    • Swollen lymph nodes, often a sign of infection (e.g., bubonic plague).

39. What is a splenectomy?

    • Surgical removal of the spleen.

40. What do the tonsillar crypts do?

    • Trap bacteria and particles for immune response.

41. Where does the thoracic duct originate?

    • From the cisterna chyli in the abdomen.

42. What is the function of the bronchomediastinal trunk?

    • Drains lymph from the thoracic organs.

43. How is lymph moved without a central pump?

    • Via muscle contractions, arterial pulsations, and one-way valves.

44. What is the significance of memory lymphocytes?

    • They provide long-term immunity after infection.

45. What happens if the thymus fails to develop properly?

    • T cells may not mature properly, leading to immune deficiencies.

46. How do lymph nodes help in cancer detection?

    • They filter cancer cells, and swollen nodes may indicate metastasis.

47. Why are the palatine tonsils most often removed?

    • They are the largest and most frequently infected.

48. What is reticular connective tissue’s role in lymphoid organs?

    • It forms the structural framework for immune cell interactions.

49. Why do lymph nodes swell during infection?

    • Due to increased lymphocyte activity and trapped pathogens.

50. What would happen if the lymphatic system stopped functioning?

    • Fluid accumulation (edema), immune deficiencies, and nutrient transport issues.