Lymphatic Vessels & Transport
List the order of Lymph Vessels starting with the smallest.
→ Lymph capillaries, Lymph collecting vessels, lymphatic trunks, lymphatic ducts (Slide 6)
What is the primary function of lymphocytes?
→ To recognize and respond to specific antigens (Slide 20)
What is the primary function of lymph nodes?
→ To filter lymph and activate the immune system (Slide 22)
What are the two primary lymphoid organs?
→ Red bone marrow and thymus (Slide 28)
What is lymphangitis and what can it progress to?
→ Inflammation of lymphatic vessels, sepsis within hours (Slide 15)
What do lymphatic vessels help return to the cardiovascular system?
→ Interstitial fluid and leaked plasma proteins (Slides 6–7)
Which two main types of lymphocytes are found in lymphoid tissues?
→ B cells and T cells (Slide 20)
Which two regions make up the internal structure of a lymph node?
→ Cortex and medulla (Slide 22)
What are considered secondary lymphoid organs?
→ Lymph nodes, spleen, tonsils, Peyer’s patches, and appendix (Slide 28)
What visible symptom often indicates lymphangitis?
→ Red streaks on the skin along lymphatic vessels (Slide 15)
What unique structure prevents backflow in lymphatic collecting vessels?
→ One-way valves (Slide 9)
What type of cell engulfs and destroys pathogens, presenting fragments to lymphocytes?
→ Macrophages (Slide 20)
What type of vessels bring lymph into the lymph node?
→ Afferent lymphatic vessels (Slide 22)
Which lymphoid organ is the site of T cell maturation?
→ Thymus (Slide 29)
What is lymphedema?
→ Localized swelling caused by blocked or impaired lymph drainage (Slide 16)
What is the primary cause of fluid escaping from the vascular system into tissues?
→ Increased capillary hydrostatic pressure and permeability (Slide 5)
What macrophages are in the skin and mucosal membranes and deliver them to lymph nodes?
→ Dendritic cells (Slide 20)
What type of vessels carry lymph away from the node?
→ Efferent lymphatic vessels (Slide 22)
Which lymphoid organ filters blood, removes old red blood cells, and stores platelets and breakdown products of RBC?
→ Spleen (Slide 30)
What is a bubo?
→ An inflamed, swollen, tender lymph node (Slide 27)
Which major lymphatic ducts drain lymph into the venous circulation?
→ Right lymphatic duct and thoracic duct (Slide 10)
Which supportive cells produce the reticular fiber stroma in lymphoid tissues?
→ Reticular cells (Slide 20)
Why are there more afferent vessels than efferent vessels in a lymph node?
→ To slow the flow of lymph and allow more time for immune cells to act (Slide 22)
What two structural regions make up the spleen, what cells are found in each?
→ White pulp – T and B cells and Macrophages and Red pulp – RBC, Platelets, Macrophages, and B cells (Slide 30)
What term describes gross enlargement of body parts due to obstructed lymph drainage?
→ Elephantiasis (Slide 17)
Where do the lymphatic ducts drain into the cardiovascular system?
→ At the junction of the internal jugular and subclavian veins (Slide 11)
What is the primary role of lymphoid tissue?
→ To house lymphocytes and provide sites for immune surveillance and activation (Slide 21)
Why are lymph nodes often swollen during infection?
→ Increased lymphocyte proliferation and macrophage activity (Slide 23–24)
What is the primary role of Peyer’s patches in the small intestine?
→ To monitor intestinal bacteria and prevent pathogen growth (Slide 35)
What parasitic infection can cause extreme, chronic lymphedema?
→ Filariasis (leading to elephantiasis) (Slide 17)
How do skeletal muscle contraction and respiratory movements aid lymph transport?
→ By generating pressure changes that squeeze lymph through vessels (Slides 12–13)
Differentiate between lymphoid nodes and lymph nodes.
→ Lymphoid nodes: Unencapsulated dense groupings of lymphocytes and reticular fibers, local surveillance of mucosa, found in MALT, tonsils, peyers patches and the appendix. Lymph nodes: Encapsulated organ with a cortex and medulla, lymph flows into and out of them for filtering, clustered in cervical, axillary, and inguinal regions (Textbook)
How does lymph circulate through a node from entry to exit?
→ Afferent vessels → subcapsular sinus → cortex → medulla → efferent vessels (Slide 26)
How do tonsillar crypts contribute to immune defense?
→ They trap bacteria and debris to expose them to lymphocytes (Slide 31)
Why does impaired lymphatic drainage result in persistent swelling rather than temporary edema?
→ Fluid cannot be returned to venous circulation, leading to chronic accumulation (Slides 16–17)
Why is lymph flow considered a low-pressure system compared to blood flow?
→ It lacks a central pump and relies on external mechanisms like muscle and thoracic pumps (Slides 12–13)
How does the structure of lymphoid tissue support immune system function?
→ Provides a reticular fiber network for lymphocytes and macrophages to interact with antigens in tissues within the mucosal layer of organs (Slide 21)
Which immune cells are primarily located in the lymph node cortex?
→ B cells (in follicles/germinal centers) and T cells (in deeper cortex) (Slide 22–23)
How many types of tonsils are there, and where are they?
→ Palatine tonsils – either side of the posterior end of the oral cavity, Lingual tonsils – lie at the base of the tongue, Pharyngeal tonsil – posterior wall of the nasopharynx, Tubal tonsils – surround the openings of the auditory tubes into the pharynx (Slide 33)
How might buboes be clinically useful in diagnosing systemic infection?
→ They indicate sites of pathogen capture and immune activity (Slide 27)
A patient has swelling in the right upper limb only. Which duct is most likely blocked?
→ Right lymphatic duct (Slide 10)
A biopsy shows a germinal center in a lymphoid follicle. What process is occurring there?
→ Proliferation of activated B cells into plasma cells and memory B cells (Slide 21, Supplemental discussion)
A patient’s lymph node biopsy shows abnormal architecture with blocked sinuses. Predict the effect on immune function.
→ Impaired filtration of pathogens and reduced immune response (Slide 26, Supplemental discussion)
A child has their thymus removed early in life. Predict the long-term immune consequence.
→ Severely reduced T cell population, impairing adaptive immunity (Slide 29, Supplemental discussion)
A patient presents with recurrent red streaks and fever. Which lymphatic pathology is most likely? Explain.
→ Lymphangitis; due to bacterial infection spreading into lymphatic vessels (Slide 15, Supplemental discussion)
Why is it essential that lymphatic vessels are highly permeable with minivalves?
→ To allow entry of proteins, pathogens, and debris that blood capillaries cannot reabsorb (Slide 8)
Compare the immune roles of B cells and T cells.
→ B cells: humoral immunity (produce antibodies); T cells: cell-mediated immunity (attack infected cells, coordinate response) (Slide 20)
Compare the role of macrophages and lymphocytes inside lymph nodes.
→ Macrophages: phagocytose and present antigens; lymphocytes: mount adaptive immune response (Slide 22–23)
Compare the immune functions of the spleen and thymus.
→ Spleen filters blood and initiates immune response; thymus provides T cell maturation but does not directly fight antigens (Slides 29–30)
Compare lymphedema caused by tumor removal vs. parasitic infection.
→ Tumor removal blocks drainage surgically; parasites block vessels internally, both leading to swelling (Slides 16–17)
Explain how obstruction of lymphatic drainage could alter capillary exchange.
→ It prevents return of excess interstitial fluid, disrupting balance of hydrostatic and osmotic forces, leading to edema (Slides 5, 8, 12–13)
Why are dendritic cells considered the most effective antigen-presenting cells in initiating adaptive immunity?
→ They migrate to lymph nodes from the skin and mucosal membranes to present captured antigens directly to naïve T cells, activating them (Slide 20, Supplemental discussion)
Explain how the slowed flow of lymph enhances the adaptive immune response.
→ Gives lymphocytes and APCs time to recognize and respond to antigens (Slide 22–26)
Why are secondary lymphoid organs strategically located at body entry points (like tonsils and Peyer’s patches)?
→ To provide rapid immune responses where pathogens are most likely to enter (Slides 31, 35–36)
Why can advanced elephantiasis lead to impaired immune function in affected tissues?
→ Stagnant lymph prevents antigen transport and immune cell activation (Slide 17, Supplemental discussion)
A patient undergoes surgery removing lymphatic vessels near the left subclavian vein. Predict the consequence and explain why.
→ Lymph from most of the body (via the thoracic duct) cannot reenter circulation, causing systemic edema and immune compromise (Slides 10–11, Supplemental discussion)
A patient has reduced numbers of reticular cells. Predict the impact on lymphoid tissues.
→ Weakened structural support and reduced antigen-lymphocyte interactions, impairing immune surveillance (Slides 20–21)
A patient has surgically removed lymph nodes in the axillary region. Predict two major consequences.
→ Reduced local immune surveillance and impaired lymph drainage → arm edema (Slides 22–26, Supplemental discussion)
A patient has surgical removal of the spleen (splenectomy). Predict two consequences and explain.
→ Increased risk of bacterial infections (due to loss of blood filtration) and impaired clearance of old RBCs (Slide 30, Supplemental discussion)
A patient has recurrent swollen, painful nodes after untreated bacterial infections. Explain the mechanism behind these chronic buboes.
→ Persistent antigen exposure overstimulates lymphocyte proliferation and macrophage activity, causing repeated node inflammation (Slide 27, Supplemental discussion)