Terms in this set (22)
large phagocyte found in lymph nodes and other tissues of the body
how do activated lymphocytes enter circulation?
through the gaps between the specialized endothelial cells in the nodal venule; these venules are called high endothelial venules (HEV). Lymphocytes in the blood can also enter the lymph node through a HEV.
Lymphatic capillaries definition and function
collecting vessels, collect lymph (interstitial fluid)
10-50 µm in diameter
composed of a single layer of endothelial cells
Lymphatic anchoring filaments definition and function
tether the vessel to the tissue. Fluid, protein, and fine particles are easily absorbed through the large intercellular clefts (14+ nm) in the terminal lymphatic
does interstitial fluid usually flow into or out of lymphatic vessels? why?
lymphatic pressure is low
what causes movement of lymph from interstitium into lymphatic capillaries, and from lymphatic capillaries into collecting lymphatics?
what does rate of lymph flow into lymphatic capillaries depend on?
interstitial volume and Pi
4 things that promote lymph flow
Skeletal muscle pump
Respiratory muscle pump
Deformation of tissue with movement
Smooth muscle contraction in larger lymphatics
Why is smooth muscle contraction needed to pump lymph?
because venous pressure > lymphatic pressure. So lymphatic pressure must be increased to empty lymph into veins.
What do SMCs generate in lymph? Which channels are responsible?
these cells generate actions potentials due to opening of fast sodium channels and L-type Ca++ channels
what increases lymphatic stroke volume and contraction frequency?
Where does afferent lymph go?
lymph node absorption
thoracic duct flow
excess water filtration and expansion of intersitial fluid
↑ Pc, surface area, pi i lead to...
seen in hard exercise--acute local edema
acute local edema pathway
Muscle contraction-->dilation of resistance vessels-->↑ Pc-->↑ capillary recruitment --> ↑ surface area --> lactate and K+ released from muscle-->↑ pi i
* Chronic excess interstitial fluid due to many causes
* Detrimental because excess interstitial fluid ↑'s diffusion distance from
capillary to cells
* Dangerous in lung
under what 4 circumstances is capillary filtration rate > lymphatic drainage rate? (pathological edema)
↑ Pc: occurs when venous pressure is raised
↓pi p: this decreases the absorptive force into capillary
3) Lymphatic insufficiency
what causes Pc to increase?
right or left ventricular failure, over transfusion, deep vein thrombosis, gravity (ankles, sacrum)
What causes decreased pi p?
malnutrition (inadequate protein), intestinal malabsorption of protein, kidney disease (protein leakage into urine), liver disease (↓ synthesis of plasma proteins)
when does lymphatic insufficiency occur?
idiopathic (poor development of lymphatics, damage (e.g., surgery), worm infestation - filariasis found in developing nations, leads to elephantiasis
↑ Lp, ↓ reflection coefficient, ↑ Pc cause
an increase filtration of water and protein
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