System Structure: Lymphatic & Immune - Massage and Bodywork Licensing Examination Mblex

1. What is the primary function of cytotoxic T cells (CD8+ T cells)?

   Directly kill virus-infected cells and tumor cells. These cells induce apoptosis in compromised host cells via perforin and granzymes to limit infection spread.

2. Which body regions drain into the right lymphatic duct?

   Right head/neck, right thorax, and right upper limb. These areas correspond to the right upper quadrant, ensuring balanced lymph return without overloading the thoracic duct.

3. What are the initial lymphatic vessels called, and what is their key structural feature?

   Lymph capillaries; blind-ended with overlapping endothelial flaps. These vessels initiate lymph collection from tissues, with their closed ends and flap-like structures allowing unidirectional fluid entry.

4. What is lymph?

   Interstitial fluid that has entered lymphatic vessels. It forms when excess tissue fluid, containing proteins and waste, is collected by lymphatic capillaries for transport and filtration.

5. What is the primary mechanism that propels lymph through lymphatic vessels?

   Skeletal muscle pump aided by respiratory pressure changes. Muscle contractions compress vessels, while breathing creates thoracic pressure gradients, driving lymph without a dedicated pump.

6. What is the function of valves in lymphatic collecting vessels?

   Prevent backflow and ensure one-way lymph movement. Similar to venous valves, they maintain unidirectional flow toward the heart, countering gravity and low pressure in the system.

7. What is a lacteal, and what does it absorb?

   Lymph capillary in intestinal villi that absorbs dietary fats (chyle). Located in villi, it bypasses portal circulation to transport emulsified lipids directly into the lymphatic system as milky fluid.

8. What is a lymph node?

   A filtering organ that removes pathogens and activates lymphocytes. It acts as a secondary lymphoid organ where lymph is filtered and immune cells encounter antigens to initiate responses.

9. What is the correct order of lymph flow through a lymph node?

   Afferent vessels → sinuses → efferent vessels. This pathway allows lymph to percolate through the node's interior for filtration and immune activation before exiting.

10. What is the right lymphatic duct, and where does it drain?

    Drains right upper quadrant into right venous angle. This smaller duct handles lymph from the right upper body, returning it to the corresponding venous junction for blood integration.

11. What is adaptive (specific) immunity?

    Antigen-specific immunity mediated by B and T lymphocytes with memory. It targets specific pathogens through lymphocyte activation, providing long-term protection via immunological memory.

12. Which vessels bring lymph into a lymph node, and which carry it away?

    Afferent vessels enter; efferent vessels exit at the hilum. Afferent vessels deliver unfiltered lymph for processing, while efferent vessels remove filtered lymph at the node's indented region.

13. What is the primary function of the lymphatic system in maintaining fluid balance?

    Return excess interstitial fluid and plasma proteins to venous blood. This process prevents tissue edema by recycling fluid and proteins that leak from blood capillaries back into circulation.

14. What is the function of macrophages within lymph node sinuses?

    Phagocytose debris and pathogens from lymph. These resident cells engulf and destroy foreign particles and damaged cells as lymph flows through the node's trabecular spaces.

15. What is the primary function of helper T cells (CD4+ T cells)?

    Coordinate immune responses via cytokines; activate B cells and T cells. They release signaling molecules to enhance and direct both humoral and cell-mediated immune activities against invaders.

16. Which structures in lymph capillaries act as one-way microvalves for fluid entry?

    Overlapping endothelial cells (mini-valves) anchored by filaments. These cells form gaps that open under high interstitial pressure to admit fluid, while filaments prevent collapse and ensure one-way flow.

17. What is chyle?

    Milky lymph rich in absorbed lipids from the small intestine. Formed post-fat digestion, its lipid content gives a white appearance and is routed via the thoracic duct to venous blood.

18. What is innate (nonspecific) immunity?

    Immediate defense using barriers, phagocytes, inflammation, and complement. This first-line system responds rapidly to threats without specificity or memory, using physical and chemical defenses.

19. What is the thymus, and what is its key immune role?

    Primary lymphoid organ where T lymphocytes mature. Located in the mediastinum, it educates immature T cells to recognize self vs. non-self antigens before release into circulation.

20. What is the spleen's primary immune function?

    Filters blood, removes old RBCs, and mounts immune responses. As the largest lymphoid organ, it monitors circulating antigens, recycles iron, and supports lymphocyte proliferation against threats.

21. What is the function of lymphatic collecting vessels?

    Transport lymph toward lymph nodes and then to lymphatic ducts. They gather lymph from capillaries, passing it through nodes for immune surveillance before reaching larger ducts for venous return.

22. Which lymphoid tissue in the small intestine monitors gut pathogens?

    Peyer patches (aggregated lymphoid nodules). These structures in the ileum sample intestinal antigens to trigger localized immune responses against microbial invaders.

23. What is the primary function of B lymphocytes in adaptive immunity?

    Differentiate into plasma cells that secrete antibodies. Upon antigen recognition, B cells proliferate and mature to produce soluble proteins that neutralize extracellular threats.

24. What is the thoracic duct, and where does it drain into the venous system?

    Largest lymphatic duct; drains into left venous angle (left subclavian–IJV junction). It collects lymph from most of the body, emptying at the venous junction to integrate with systemic circulation.

25. What is MALT, and where is it commonly found?

    Mucosa-associated lymphoid tissue in GI, respiratory, and urogenital mucosa. It provides immune protection at body entry points by housing lymphocytes that respond to pathogens breaching mucosal barriers.

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