IM 1 Flashcards
lymphatic system
- network of small organs/tissues and vessels that lymph-fluid derived from interstitial fluid - flows
- drains excess interstitial fluid and returns to blood
- returns filtered proteins to blood
- transports lipids (chylomicrons in lacteals)
- immune responses
lymphoid organs/tissues
-immune cells develop, reside, and often carry out responses
primary lymphoid organs
-develop and mature
-bone marrow
thymus
secondary lymphoid organs
- reside, carry out
- spleen (filters blood)
- lymph nodes (filter lymph)
- lymphoid nodules
- > tonsils - inhaled, ingested
- > linings - gastrointestinal, respiratory, urinary, reproductive tracts - external contact points
filtration of lymphatic system
-plasma to interstitial fluid
~ 20 L/day
absorption of lymphatic system
-interstitial fluid to plasma
~17 L/day
excess filtration of lymphatic system
~ 4 L/day (excluding kidneys)
-enters lymphatic capillaries to become lymph
interstitial fluid and lymphatic capillaries
- small amounts of interstitial fluid continuously enter lymphatic capillaries
- lymphatic capillaries closed at one end
once in lymphatic capillaries
- smaller lymphatic vessels flow one-way (valves) into larger and larger lymphatic vessel
- lymph flows through lymphatic organs/tissues along the way
- eventually enters back into veins of the cardiovascular system
what maintains lymph flow?
primarily :
- smooth muscle contractions
- distension driven
assisting :
- skeletal muscle pump
- respiratory pump
both pressure gradient driven
blockage of lymph flow
- fluid builds up in interstitial space
- can be a source of edema (swelling)
Physical external defenses -barriers
- skin : when intact prevent pathogens entering deeper tissues
- hairs : nasal cavity - filter
- mucus : upper respiratory, gastrointestinal tracts - sticky, binds pathogens
- cilia : upper respiratory tract - works with mucus to trap and remove
- reflexes : coughing/sneezing/swallowing
chemical external defenses -barriers
- sebum : oil on skin surface/ slightly acidic, poor environment for bacterial growth
- lysozyme - antimicrobial substance : tears, perspiration, saliva, nasal secretions, tissue fluids
stomach acid - highly acidic, kills many pathogens
vaginal secretions - slightly acidic, poor environment for bacterial growth/ washes out
internal defenses -leukocytes (Review/research internal defenses)
-formed in red bone marrow (leukocyte formation by leukopoiesis)
myeloid cells : myoloid stem cells - internal defenses
neutrophils - phagocytosis
basophils - cytokines, allergic reactions
eosinophils - destroy parasites allergic reactions
monocytes - circulate, mature into macrophages
