test 3: lymphatic system Flashcards
what are the 3 functions of the lymphatic system?
1) produce, maintain, and distribute lymphocytes (immune response)
2) maintain normal blood volume and composition of interstitial fluid
3) alternate route for transport of hormones and nutrient wastes
what is the composition of lymph?
1) interstitial fluid
2) lymphocytes
3) macrophages
what type of cells are lymphocytes?
agranular WBCs
primary lymphatic structures
- where lymphocytes are produced and mature
- e.g. thymus, red bone marrow
secondary lymphatic structures
- where lymphocytes are activated and receive additional support
- e.g. lymph nodes and tonsils
describe the flow of lymph
-1-way highway coming from periphery to venous system
lymphedema
damage to lymphatic vessels or if you get lymph nodes removed, system doesn’t work as well
- get pooling of lymph, swelling
- light pressure massage helps to treat
lymphatic capillaries
- sit in capillary beds
- contain one-way “valves”, made of collagenous filaments
- endothelial cells overlap one another - not a full basal lamina surrounding it
do lymphatic capillaries contain valves
- not really
- look and act like valves, but they’re really just overlapping endothelial cells - fluid goes in one way then can’t escape
how does the lumen of lymphatic vessels differ from blood vessels?
-they have a large lumen, walls are quite thin (don’t see 3 different layers like in arteries and veins)
name the lymphatic vessels from distal to proximal
- small lymphatic capillaries
- vessels (has valves)
do lymphatic vessels have valves?
-yes, bulges in lymphatic system where there are valves, muscle contraction helps move fluid along the vessels (same as veins)
what are the 5 lymphatic trunks?
1) lumbar (R/L)
2) intestinal (R/L)
3) brachiomediastinal (R/L) - drains everything from thoracic cavity
4) subclavian (R/L)
- upper extremity
5) jugular (R/L)
- head
cisterna chyli
- gather lymph from lumbar and intestinal trunks
- turns into thoracic duct when it passes the diaphragm
thoracic duct
cisterna chyli joins to form thoracic duct
- drains into left subclavian vein
- collects most of the body’s fluid
right lymphatic duct
- attaches to right subclavian vein
- right jugular, right subclavian, right brachiomediastinal
- collects a lot less fluid
what are the 2 lymphatic ducts and from which areas of the body do they collect fluid
1) right lymphatic duct
- collect fluid from right side of thoracic cavity, right arm, and right side of head/neck
2) thoracic duct
- collects from everywhere else in body
describe the movement of interstitial fluid from right ankle to heart
- Lymphatic capillary
- Lymphatic vessel
- Right lumbar trunk
- Cisterna chyli
- Thoracic duct
- Left subclavian vein
- Brachiocephalic vein
- Superior vena cava
where do lymphocytes originate from?
- production starts in red bone marrow
- T-cells activate in thymus
what are the 3 lymphocytes? Where in the body does each mature?
- T-cells (thymus)
- B-cells (red bone marrow)
- NK cells (red bone marrow)
T-cells, B-cells, and NK cells originate from which type of cells?
lymphatic stem cells
how does each lymphocyte contribute to immunity?
1) T-cells
- cell mediated immunity
2) B-cells
- antibody mediated immunity
3) NK cells
- immune surveillance
T cells
- cell mediated immunity
- attack and destroy foreign pathogens
- most abundant
- 3 types: helper (helps activate B cells), regulatory, and memory
B cells
- activated by T cells
- create antibodies to attack foreign cells
NK cells
-look for foreign bodies - attach to them and release chemical that signals that the cell is bad
what does MALT stand for?
-mucosa-associated lymphoid tissue
what systems are MALTs associated with?
- respiratory, reproductive, digestive, urinary
- where you’re exposed to different viruses and foreign bodies
what are the 2 major sites of MALTs?
1) tonsils (5)
2) appendix
name the 5 tonsils and their location
- pharyngeal (back of nasopharynx)
- L/R palatine tonsils (back of throat
- L/R lingual tonsils (base of tongue)
how is the appendix a MALT?
- contains a lot of lymphatic tissue
- when removed, lack some of the cells that produce gut bacteria
what are the 3 lymphatic organs?
1) lymph node
2) thymus
3) spleen
lymph node as a lymphatic organ
- widespread throughout the body
- cervical, axillary, popliteal, inguinal, thoracic, abdominal, intestinal, mesenteric
- should be small when healthy (1-25 mm)
thymus as a lymphatic organ
- thoracic cavity in mediastinum
- large and active in childhood - decreases in adulthood
spleen as a lymphatic organ
- LUQ
- sits between 9th and 11th rib
- processes a lot of blood, a lot of damaged blood cells in this area
- can be removed, we can function without it
- will be a bit immunocompromised however
what is the largest lymphatic organ?
spleen
what is the capsule of a lymph node
dense CT surrounding the node
what are the trabeculae in lymph nodes?
indentations protruding from capsule
what is the hilum of the lymph node?
-indentation where a lot of structures come in and out (blood vessels/lymph vessels)
describe the movement of lymph in a lymph node
- afferent vessel (there are multiple)
- cortex
- medulla
- efferent vessel (there is only one)
