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Lymphatic Sys Ch 19
A&P - Wk 6
Question | Answer |
---|---|
What is interstitial fluid called once it enters the lymphatics? | lymph |
Why are lymphatic capillaries absent from bones, teeth, bone marrow and the entire central nervous system? | these areas' excess tissue fluid drains into the cerebrospinal fluid |
What is the 'fatty' lymph that drains from the digestive viscera and delivered to the blood via the lymphatic stream called? | chyle |
What are the major lymphatic trunks? | lumbar, bronchomediastinal, subclavian and jugular trunks and intestinal trunk |
What collects lymph from the 2 large lumbar trunks that drain the lower limbs and from intestinal trunk that drains the digestive organs? | cisterna chyli |
What happens when lymphatic vessels are severely inflamed causing the related vessels of the vasa vasorum to become congested with blood? | lymphangitis - the pathway of the associated superficial lymphatics becomes visible thru the skin as red lines tender to the touch |
How does the lymphatic system transport lymph through the body? | by pulsations of nearby arteries, thythmic contractions of thoracic ducts and movement of adjacent tissues |
What is blockage of the lymphatics by tumors or removal of lymphatics during cancer surgery which prevents the normal return of lymphatics to the blood called? | lymphedema |
What are the 3 functions of the lymphatic system? | 1) return excess tissue fluid to the bloodstream; 2) return leaked proteins to the blood; 3) carry absorbed fat from the intestine to the blood (thru lacteals) |
Which cells produce plasma cells, that secrete antibodies into the blood an recognize antigens? | B cells |
What is lymphoid tissue mainly composed of except the thymus? | reticular connective tissue |
What lives on the fibers of the reticular network? | macrophages |
What lives in the spaces of the network in huge numbers? | lymphocytes that have squeezed thru the walls of postcapillary venules coursing thru the tissue |
What do lymphocytes mature into that protect the body against antigens? | T cells or B cells |
Which cells manage the immune response by directly attacking and destroying infected cells? | activated T cells |
Which cells protect the body by producing plasma cells that secrete antibodies into the blood (or other bodily fluids)? | B cells |
Where do lymphocytes arise from? | red bone marrow |
What plays a crucial role in body protection and in the immune response by phagocytizing foreign substances and by helping to activate T cells? | lymphoid macrophages, and dendritic cells |
What cells fibroblast-like cells produce the reticular fiber stroma? | reticular cells |
Where do the lymphocytes cycle between in the body? | circulatory vessels, lymphoid tissues, and loose connective tissues |
What tissue consists of a few scattered reticular tissue elements and is found in virtually every body organ? | diffuse lymphatic tissue |
What cells predominate in germinal centers (the lighter staining center of a lymphoid follicle? | follicular dendritic cells and B cells |
When do germinal centers enlarge dramatically? | When B cells are dividing rapidly and producing plasma cells |
What cells predominate in germinal centers? | follicular dendritic cells and B cells |
What are isolated aggregations of lymphoid follicles that occur in the intestinal wall and apprendix called? | Peyer's patches |
What are the principal lymphoid organs in the body and where are they found? | lymph nodes, which cluster along the lymphatic vessels of the body |
As lymph is transported back to the bloodstream the lymph nodes do what to it? | filter it |
Where do large clusters of lymph nodes occur near the body surface? | inguinal, axillary and cervical regions |
What are the primary functions of lymph nodes? | filtration of lymph; initiation of an immune response when necessary; production of new lymphocytes |
Each lymph node is surrounded by a dense fibrous capsule from which connective tissue strands called what extend inward to divide the node into a number of compartments? | trabeculae |
What 2 histologically distinct regions comprise a lymph node? | cortex and the medulla |
What does the superficial part of the cortex contain? | densely packed follicles, many with germinal centers heavy with dividing B cells |
What cells nearly encapsulate the follicles and abut the deeper part of the cortex, which primarily houses T cells in transit? | dendritic cells |
What role do the T cells perform by circulating continuously between the blood, lymph nodes and lymph? | surveillance role |
What are thin inward extension from the cortical lymphoid tissue, and contain both types of lymphocytes plus plasma cells and define the medulla? | medullary cords |
How does lymph enter the convex side of a lymph node? | Thru a number of afferent lymphatic vessels |
How does the lymph exit the node at its hilum (the indented region on the concave side? | via efferent lymphatic vessels |
What are infected lymph nodes called? | buboes |
Buboes are the most obvious symptom of what? | bubonic plague |
What do the spleen, thymus, tonsils, bits of lymphatic tissue scattered in the connective tissues and Peyer's patches of the intestine have in common? | they are all types of lymphoid organs or aggregates of lymphatic tissue in the body |
What is the only lymphatic organ not comprised of reticular connective tissue? | thymus |
What is an important function of the spleen? | blood-cleansing; extracts aged and defective blood cells and platelets and removes debris |
What 3 additional functions does the spleen perform? | 1)stores some of the breakdown products of RBC for later reuse 2) is a site of erythrocyte production in the fetus (capability that ceases after birth) 3) stores blood platelets |
The spleen contains large numbers of what? | erythrocytes |
Areas of the spleen composed mostly of lymphocytes suspended onreticular fibers are called what? | white pulp |
The white pulp clusters or forms "cuffs" around the central arteries in the spleen and appears to be islands in a sea of what? | red pulp - all remaining splenic tissue; venous sinuses and splenic cords, regions of reticular connective tissue exceptionally rich in macrophages |
What is red pulp most concerned with disposing of? | worn out red blood cells and bloodborne pathogens |
What is white pulp concerned with? | the immune functions of the spleen |
What is removal of a reuptured spleen called? | splenectomy |
The thymus causes what cells to become immunocompetent, enabling them to function against specific pathogens in the immune response | T lymphocytes |
What structures in the thymus consist of concentric whorls of keratinized epithelial cells, and are sites of T cell destruction? | thymic (Hassall's) corpuscles |
How does the thymus differ from other lymphoid organs? (2 ways) | 1) it functions strictly in T lymphocyte maturation so does not directly fight antigens 2) the stroma of the thymus consists of epithelial cells not reticular fibers |
What are the simplest lymphoid organs? | tonsils |
Which tonsils are located on either side at the posterior end of the oral cavity and are the largest and the ones most often infected? | palatine tonsils |
What tonsil is in the posterior wall of the nasopharynx? | pharyngeal tonsil |
What tonsils surround the openings of the auditory tubes into the pharynx? | tubal tonsils |
Tonsils at the base of the tongue are what? | lingual tonsils |
What function does the tonsils perform? | gather and remove many of the pathogens entering the pharynx in food or inhaled air |
What are large isolated clusters of lymphoid follicles, structurally similar to the tonsils, and are located in teh wall of the distal portion of the small intestine? | Peyer's patches |
Which follicles are heavily concentrated in the wall of the appendix? | lymphoid follicles |
What are part of the collection of small lymphoid tissues referred to as mucosa-associated lymphatic tissue (MALT)? | Peyer's patches, the appendix, and the tonsils |
Where are the MALT tissues located? | in the digestive tract |
What does MALT protect passages from? | the never-ending onslaughts of foreign matter entering them |
By what week of embryonic development, does the beginnings of the lymphatic vessels and the main clusters of lymph node become apparent? | 5th |
Where do the lymph node arise from in embryos? | from the budding of lymph sacs from developing veins |
How can pathogens and cancer cells spread thru the body? | via the lymphatic stream |
What are the cells in lymphoid tissues? | lymphocytes (T cells or B cells); plasma cells; macrophages; dendritic cells; reticular cells |
What are the principal lymphoid organs? | lymph nodes |
Each lymph node consists of what 3 things? | fibrous capsule; cortex and a medulla |
Lymphocytes arise from what tissue? | hematopoietic tissue |
What regions are drained by the right lymphatic duct? | right arm, right side of head, and right side of upper body |
What regions are drained by the thoracic duct? | the left side of head, left side of upper body and entire lower body |
What are lymphatic capillaries called in the intestinal mucosa? | lacteals |
How does chyle differ from lymph? | chyle is a milky bodily fluid consisting of lymph and emulsified fats and the composition of lymph is clear, watery fluid that contains protein molecules, salts, glucose, urea, |
Why should a badly infected part of the body be immobilized? | So as not to spread the infection via lymph transport |
What other forces assist with lymphatic return? | skeletal muscle contraction, contractions of the lymphatic vessels |
Where does the thoracic duct empty into? | the left subclavian vein |
Where does the right lymphatic duct empty into? | the right subclavian vein |
What comprises lymphatic tissues? | nodules and lymphatic organs |
What are inflamed pharyngeal tonsils, located in the nasopharynx called? | adenoids |
What are the most common tonsils located at the posterolateral aspect of the oral cavity called? | palatine tonsils |
Which tonsils are found on the root of the tongue? | lingual tonsils |