Lymphatic System Flashcards
lymphatic system is composed of 7 things, what are they
1 - diffuse lymphatic tissue 2 - lymphatic nodules 3 - lymph nodes 4 - spleen 5 - bone marrow 6 - thymus 7 - lymphatic vessels
what are the 3 major functions of the lymphatic system
1 - drain excess interstitial fluid, return to circulation
2 - immune response - prod. of lymphocytes
3 - alt. route of transportation for hormones, nutrients, etc
what component of the lyphatic system is responsible for draining excess interstitial fluid and being the alternative route of transportation for many things
lymphatic vessels
what 3 components of the lymphatic system are characterized as the lymph organs ? Why ?
lymph nodes, spleen, and thymus
Cuz all have capsules
exchange b/w circulation and lymphatic vessels occurs where ?
lymphatic capillaries
what is the definitive cells of the lymphatic system
lymphocytes
through what type of vessel is lymph drained in the capillary beds returned back to the circualtion
lymphatic ducts
what are the 2 lymphatic ducts and what do they each drain
right lymphatic duct - returns upper right of body (1/4)
thoracic duct - returns upper left and lower body (3/4)
where is the junction of veins that the right lymphatic duct and thoracic duct return lymph ?
Venous angle between IJV and subclavian vv.
-on each side
what are the 2 distinguishing characteristics in identifying lymphatic capillaries
- irregular lumen
- NO RBC
the lumen of lymphatic vessels are all lined w/ ?
discontinuous endothelium
-simple squamous epithelium
what are the 3 main lymphocytes
1 - B cells
2 - T cells
3 - NK cells
what is the distribution of lymphocytes in blood circulation ?
T cells : 60-80 %
B cells : 20-30 %
NK : 5-10 %
what is the function of each type of lymphocyte
B - secrete Ab in humoral immunity
T - destroy cells in cell-mediated immunity
NK - kills
in general what do reticular cells do
lay down type III collagen to make a stroma or filamentous framework/network for lymphocytes to grab onto in most lymph organs
what type of cells make the supportive stroma or network in the thymus
epithelioreticular cells
what type of valves do lymphatic capillaries have
one way valves
diffuse lymphatic tissue is simply accumulations of lymphocytes where ?
in the lamina propria of various canals and tracts
where would you find lymphatic nodules ?
accumulations of lymphocytes in the walls of various canals and tracts
what are the 2 types of lymphatic nodules
1 - primary nodule
2 - secondary nodules
what are the two zones of secondary lymphatic nodules
inner germinal center (light stained)
outer mantle zone (dark stained)
what is the main difference b/w primary and secondaary lymphatic nodules
primary has NOT responded to Ag
secondary has larger lymphocytes cuz they HAVE responded to Ag (activated)
where would you find follicular dendritic cells (FDC’s) ?
germinal centers of secondary lymphatic nodules
normally lymphatic nodules are found by _______ but sometimes in certain locations they can be found in ___ ?
themselves (solitary nodules)
aggregations
where at in the human body would you most likely find aggregated lymphatic nodules
tonsils, and peyers patches in ileum
what tonsils make up the ring around the entrance to the oropharynx and nasopharynx
1 pharyngeal tonsil
2 - palatine tonsils
2 - lingual tonsils
What is MALT, and what other places in the body have more location specific names
mucous-associtated lymphoid tissue (accumulations of diffuse lymphatic tissue and lymphatic nodules
-GALT and BALT
lymph nodes are the predominant filtering system for lymphatic vessels, what are the 5 layers of lymph nodes from out to in
capsule, trabeculae, reticular tissue/network, cortex, medulla
what are the 2 layers of the cortex of lymph nodes, and which layer contains lymphatic nodules
superficial cortex (nodular cortex) deep cortex (paracortex)
what type of lymphocytes can be found at each layer of the lymph node cortex, what about lympn node medulla
superficial cortex - B cells
deep cortex - T cells
medulla - B cells
what are the 2 parts of the medulla layer in lymph nodes
- medullary cords (groups of B cells)
- medullary sinuses (places where lymph flows)
what specific types of cells would you find in the reticular network of lymph nodes
- reticular cells (secrete type III collagen)
- APC’s (dendritic cells, macrophages)
what part of the lymph node has NO cortex
at the hilum
what specific lymph vessel can be found at the hilum of a lymph node and what is its function
efferent lymphatic vessel
-returns lymph back to circulation
explain the path of lymph flow through the lymph node
afferent lymph vessel—->subcapsular sinus —-> trabecular sinus —> medullary sinus —-> efferent lymph vessel
90 % of lymph flows into the lymph node from ________ whereas the remaining 10 % comes in from ______
90 % - High endothelial venules (HEV)
10 % - afferent lymph vessel
what is the function of the thymus in the lymphatic system
T cell education and maturation and differentiation
what lymph organ has NO reticular cells
thymus
what is an easy indicator to identify the thymus
thymic lobules and thymic corpuscle
what are the 2 parts to a thymic lobule
- darker outer cortex
- lighter inner medulla
how many types of epithelial cells are found in the thymus
6 total
- 3 in cortex and 3 in medulla
the thymic corpuscle is unique b/c it very eosinophillic and starting what process
keratinization
what is the function of the spleen
fliter and monitor blood immunologically just as lymph nodes monitor lymph vessels
what are the 2 areas of the spleen
Red pulp
white pulp
What is interesting in the naming of the red and white pulp ?
named according to red referring to filtering RBC NOT to how they stain
- Red pulp is lighter outside area
- White pulp is darker inner ring
what is the white pulp and what does it surround
it is a periarterial lymphatic sheath (PALS) around a central a.
what part of the spleen is involved in filtration and removing old RBC
red pulp
where at in the spleen would you find splenic sinuses and splenic billiroth cords
red pulp
