Lymphatics Flashcards
what are lymphatic vessels?
collect tissue fluid from loose connective tissue by carrying fluid to great veins in the neck; fluid flows only towards the heart
what are the functions of the lymphatic vessels?
- Absorption of dietary fats
- Delivering fats to the bloodstream
- Collecting of excess interstitial fluids
- Delivering excess fluids to the bloodstream
- Delivering foreign particles to the lymph nodes
what are the lymph nodes?
scattered along collecting vessels
what are the lymph trunks?
collect lymph from collecting vessels
what the lymph ducts?
empty into veins of the neck
where are the lymphatic capillaries located?
Located near blood capillaries
what do lymphatic capillaries receive tissue fluid from?
connective tissues
- increased volume of tissue fluid
- minivalve flaps open and allow fluid to enter
the high permeability of lymphatic capillaries allows entrance of?
tissue fluid
bacteria, viruses, and cancer cells
what are lacteals?
- specialized lymphatic capillaries
- receive digested fats
- located in the villi of the small intestines
- fatty lymph – chyle
what are lymphatic collecting vessels?
Accompany blood vessels
what are lymphatic collecting vessels composed of?
Composed of the same three tunics as blood vessels
1: tunica intima; layer of endothelial cells
2: tunica media; circularly arranged elastic fibers,
smooth muscle in arteries,
3: tunica adventitia; connective tissue
why do lymphatic collecting vessels contain more valves than the veins do?
helps direct the flow of blood
what is lymph propelled by?
bulging of skeletal muscles
pulsing of nearby arteries
tunica media of the lymph vessels
what are lymph nodes?
Cleanse the lymph of pathogens
Human body contains around 500
Lymph nodes are organized in clusters
what is the lymph node fibrous capsule?
surrounds lymph nodes
what is the lymph node Trabeculae?
connective tissue strands
what are the lymph vessels?
Afferent lymphatic vessels
Efferent lymphatic vessels
what are lymph trunks?
Lymphatic collecting vessels converge
what are the five major lymph trunks?
lumbar trunks intestinal trunk Bronchomediastinal trunk Subclavian trunks Jugular trunks
what are the lumbar trunks function?
receives lymph from lower limbs
what is the function of the intestinal trunk?
receives chyle, digestive organs
what is the function of the Bronchomediastinal trunk?
collects lymph from thoracic viscera
what is the function of subclavian trunks?
receive lymph from upper limbs and thoracic wall
what is the function of the jugular trunks?
drain lymph from head & neck
what are cisterna chyli?
located at the union of lumbar and intestinal trunks
what are the lymph ducts?
cisterna chyli
thoracic duct
right lymphatic duct
what are is the thoracic duct?
Ascends along vertebral bodies
Empties into venous circulation
Junction of left internal jugular and left subclavian veins
Drains three quarters of the body
what is the right lymphatic duct?
empties into right internal jugular and subclavian veins
what is the specific purpose of the immune system?
Recognizes specific foreign molecules
Destroys pathogens effectively
what are the key cells of the immune system?
lymphocytes, also lymphoid tissue and lymphoid organs
what are lymphocytes?
Infectious organisms attacked by inflammatory response
how does a lymphocyte start out?
macrophages, then lymphocytes
what are examples of the lymphocytes?
Cytotoxic T lymphocytes
B lymphocytes
what are Cytotoxic T lymphocytes?
Attack foreign cells directly
Binds to antigen-bearing cells
Perforates cell membrane
Signals cell to undergo apoptosis
what are B lymphocytes?
become plasma cells
secrete antibodies, mark cells for destruction by macrophages
what are the different types of antibody classes?
IgA IgD IgE IgG IgM
what is IgA?
monomer in plasma; dimer in mucus, saliva, tears, milk, intestinal secretions, prevents adherence to epithelia
what is IgD?
monomer; B cell membrane antigen receptor
what is IgE?
monomer; on mast cells; stimulates release of histamines, attracts eosinophils; immediate hypersensitivity reactions
what is IgG?
monomer, 80% circulating, crosses placenta to fetus, 2 immune response, complement fixation
what is IgM?
pentamer, 10% in plasma, 1st degree immune response, agglutination, complement fixation
what is the most important tissue of the immune system?
lymphoid tissue
where are lymphoid tissues located?
Mucous membranes of digestive, urinary, respiratory, and reproductive tracts
- Mucosa-associated lymphoid tissue (MALT)
Lymphoid organs (except thymus)
what are the primary lymphoid organs?
Bone marrow
Thymus
what are the secondary lymphoid organs?
Lymph nodes, spleen, tonsils
Aggregated lymphoid nodules
Appendix
what are lymphoid organs?
Designed to gather, destroy infectious microorganisms
what is the thymus?
Immature lymphocytes develop into T lymphocytes that secrete thrice hormones
T/F, Functional tissue atrophies with age
T
what is the thymus composed of?
cortex and medulla, where the medulla contains Hassall’s corpuscles (thymic corpuscles)
how does the thymus differ from other lymphoid organs?
- functions strictly in lymphocyte maturation
- arises from epithelial tissue
what is the functional pathway of the lymph nodes?
Lymph percolates through lymph sinuses
Most antigenic challenges occur in lymph nodes
Antigens destroyed – activate B and T lymphocytes
what is the spleen?
largest lymphoid organ used to remove blood borne antigens and the removal/destruction of old or defective blood cells
this is the site of hematopoiesis in the fetus
spleen
this is the site of B cell maturation into plasma cells?
spleen
T/F, the spleen is the storage of platelets?
spleen
what are the major organs of the lymphatic system?
lymph nodes
thymus
spleen
what are the tonsils?
Arranged in a ring to gather and remove pathogens
what are the four groups of tonsils?
palatine, lingual, pharyngeal, and tubal tonsils
what are some disorders of the Lymphatic and Immune Systems?
chylothorax lymphangitis mononucleosis Hodgkin's disease Non-Hodgkin's lymphoma
