LYMPH 1 Flashcards
what does the lymphatic system consist of
lymphatic vessels and various lymphoid tissues and organs scattered throughout the body
why does fluid leak out of capillary bed
pressure in beginning part of capillary bed
is greater than surrounding tissue; as a result,
fluid leaked out; most fluid is reabsorbed, but not all up to lymphatic system to pick the rest up
what does the lymphatic system drain
Drain body fluids and return to bloodstream to maintain blood volume
what does the lymphatic system transport
dietary lipids (and lipid-soluble vitamins)
what does the lymphatic system facilitate
immune responses (i.e., initiate highly specific responses directed against particular microbes or abnormal cells)
is the lymphatic system one way
yes
whats the pathway for lymphatic system
CICVTDS
Blood capillaries → Interstitial spaces → Lymphatic capillaries → Lymphatic vessels → Lymphatic trunks → Lymphatic ducts → Subclavian veins
how do lymphatic capillaries compare to blood capillaries
slightly larger
are lymphatic capillaries permeable
yes
where are lymphatic capillaries located
Located everywhere except CNS, bone marrow, bones, teeth, cornea
what area are lymphatic capillaries located
where interstitial fluid enters lymphatic
system
what about endothelial cells makes lymphatic capillaries permeable
Endothelial cells are not tightly joined, so edges of cells are loosely overlapped creating valves
what does collagen do to endothelial cells
collagen anchors the endothelial cells (walls) to surrounding structures
what does collagen anchoring endothelial cells allow for
allows for any increase in interstitial fluid to put pressure on the valves and open them
what happens when interstitial fluid pressure > capillary fluid pressure
Flap opens and lymph enters lymphatic capillaries
what happens when capillary fluid pressure > interstitial fluid pressure
flaps close
why is the permeability of lymphatic system a double-edge sword
Proteins enter easily, along with pathogens, cell debris and cancer cells (double-edged sword)
what are lacteals
Highly specialized lymphatic capillaries in the intestinal mucosa
what do lacteals play a major role in
absorbing digested fats/capturing fat
what is the lymph in lacteals called
chyme, with a milk color because of high fat content (instead of being transparent)
where do lacteals sit
alongside microvilli
how are initial lymphocytes different from capillaries
have many inter- endothelial junctions
what do lymphocyte vessels do
Act as one-way microvalves (primary lymph valves)
what do the walls of larger collecting lymphocytes contain
consisting of endothelium and sparse smooth muscle
