Lymphatic System Flashcards
Lymphatic capillaries contain flaplike _________ which allow fluid to only move in and not out of the capillaries. Fluid moves in only when the hydrostatic pressure is greater outside of the capillary than inside of it.
minivalves (made of overlapping endothelial cells anchored by collagen fibers)
True/False. Lymphatic capillaries are more permeable than blood capillaries.
True- large molecules like proteins, pathogens, and cancer cells can pass across the plasma membrane.
This specialized set of lymphatic capillaries transport absorbed fats from the small intestine to the blood stream. This fatty lymph is called chyle.
Lacteals
What is the sac at the end of the intestinal trunk that chyle drains into?
Cisterna chyli (part of thoracic duct).
Organize these vessels from smallest to larges. Lymphatic trunks, ducts, collecting vessels, and capillaries.
Capillaries-collecting vessels-trunks-ducts
Name the two main ducts in the lymphatic system that drain into the blood near internal jugular and subclavian veins. Which one drains the right side of the head and thorax and right upper limb?
Thoracic duct and right lymphatic duct; right lymphatic duct. The thoracic drains lymph from the rest of the body.
This condition is caused when the vasa vasorum of larger lymphatics becomes congested with blood.
Lymphangitis (site of infection distal to inflammation due to one way flow of lymph)
Lymphedema (severe localized edema) is the result of a blockage of lymph returning to the blood. Name one or two things that might cause this.
Cancer/tumor, removal of lymphatics due to cancer
________cell produces the _______ fiber stroma, which is the network that supports other cell types in lymphoid organs.
Reticular
Activated B-cells produce _______ cells which secrete anti-bodies into the blood.
plasma
This specialized macrophage is found mainly in the skin and mucous membranes. After using it longs arms to grab an invader, it enters the lymphatics and presents part of the invader to T-cells.
Dendritic cell
Name the two types of lymphoid tissues
Diffuse lymphoid tissue and lymphoid follicles
Lymphoid follicles are tightly packed spherical bodies of lymphoid cells and reticular fibers. The _______ is where proliferating B cells dominate. The exterior ______ is where resting and memory B cells hang out.
germinal center, mantle
Lymphoid follicles are found mainly in lymph nodes, the appendix, and ______ ________, isolated aggregations in the intestinal wall.
Peyer’s patches
Lymphoid tissue is largely composed of _______ connective tissue. Macrophages live on the fibers of this network.
reticular
Name the primary lymphoid organs
Red bone marrow (B cells mature here) and thymus (T cells mature here)
______ _______ ______ are where mature lymphocytes first encounter antigens and are activated.
Secondary lymphoid organs (lymph nodes, spleen, MALT (tonsils, Peyer’s patches, appendix).
Which secondary lymphoid organs cleanse the lymph and activate the immune system?
Lymph nodes (large clusters are found in the inguinal, axillary, and cervical regions
Macrophages and plasma cells are found in the _____ of the lymph node.
Medulla
T-cells and dendritic cells are found in the _____ of the lymph node.
Paracortex
B-cells, follicular dendritic cells, and subscapular macrophages are found in the ______ of the lymph node.
Cortex
What benefit is there of lymph nodes having more afferent vessels than efferent vessels?
Slows the flow of lymph
Afferent lymphatic vessels-> subscapular sinus->cortical sinus->medullary sinus->efferent lymphatic vessels (exits via hilum). This describes the flow of lymph through _____ _____.
Lymph nodes
This can form when the the nodes are overwhelmed by infection leading to inflamed, swollen, and tender lymph nodes.
Buboes (bubonic plague named after these)
Largest lymphoid organ critical to blood cleansing functions and is home to a large number of lymphocytes and macrophages.
Spleen
This part of the spleen is where immune functions take place (composed mostly of lymphocytes on reticular fibers) and clusters around central arteries.
White pulp
Consists of splenic cords, regions of reticular CT, that separate the blood-filled splenic sinusoids. Worn-out blood cells and bloodborne pathogens are also destroyed here.
Red pulp
True or false. In children younger than 12, the spleen will regenerate if a small part is left in the body.
true
What does MALT stand for and what are the 3 largest collections in the body?
Mucosa-associated lymphoid tissues; tonsils, Peyer’s patches, appendix
The 4 tonsils (all of which contain lymphoid follicles with germinal centers) are palatine, lingual, pharygeal, and tubal tonsils. Name their location.
Palatine- posterior end of oral cavity, lingual- base of tongue, pharyngeal-posterior wall of nasopharynx, tubal- openings of pharyngotympanic tubes
This invagination of epithelium is where bacteria gets trapped and destroyed in the tonsils.
tonsillar crypts
This MALT destroys bacteria and prevents breach of the intestinal wall. They contain clusters of lymphoid follicles.
Peyer’s patches
This offshoot of the large intestine contains a large number of lymphoid follicles and performs a similar function to Peyer’s patches as well as protecting gut flora.
Appendix
T-lymphocytes become immunocompetent in this bilobed structure.
Thymus
True/false. The thymus is most active and largest during adulthood.
False
_____ ______ , like flowerets of cauliflower, contain an outer cortex of immature T cells and an inner medulla of mature T cells.
Thymic lobules
Thymic corpuscles, located in the medullary area of the lobule, are involved in the development of _____ _____, a class of lymphocytes important for prevent ________ response.
regulatory T cells; autoimmune
How does the thymus differ from secondary lymphoid organs?
No follicles (lacks B cells), doesn’t directly fight antigens (strictly maturation site for T cells), stroma consist of epithelial cells rather than reticular fibers.
