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46 Cards in this Set
- Front
- Back
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What do LANA and NLN stand for?
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LANA - Lymphology Association of North America
NLN - National Lymphedema Network |
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What are 2 arterial functions?
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1. transport oxygen and nutrients to tissues
2. carry immune cells (lymphocytes) to fight infections |
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What are 2 venous functions?
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1. carry deoxygenated blood back to heart
2. act as a reservoir for blood |
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What are 2 capillary function?
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fluid and nutrient exchange
1. ultrafiltration -- blood to vital organs/tissues, from arterial ends 2. reabsorption -- blood back into the vessels, venous end |
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What is the difference between ultrafiltration and reabsorption?
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ultrafiltration -- arterial end, oxygen rich blood leaves arteries for tissues
reabsorption -- venous end, oxygen poor blood returns to bloodstream when tissue hydrostatic pressure is high |
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What is the lymphatic component to the blood stream?
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- fluids and proteins leak to tissues
(part of ultrafiltration) - lymph vessels carry excess protein-filled fluid back to lymph nodes via lymph vessels |
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How does lymphedema differ from other types of edema?
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protein-rich edema
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What are 3 lymphatic circulatory functions?
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1. recycle (remove excess fluids/proteins from tissues to return to blood stream)
2. garbage collection (removes waste products from tissues) 3. alarm system (carries antigens to lymph nodes to alert immune system) |
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What is the purpose of a lymph node?
Where are there large concentrations of nodes? |
filtration of lymph
around organs |
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How does the lymphatic system relate to venous insufficiency?
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OLD BELIEF: venous end of capillaries absorbed much of the fluid excess
NEW BELIEF: lymphatics take up majority of the excess tissue fluid IMPORTANCE? veins aren't taking up excess fluid, there isn't a lot of edema unless the lymphatic system isn't working properly |
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What are 4 components of microcirculation?
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1. capillaries
2. tissue channels 3. proteolytic cells (macrophages) 4. initial lymphatics |
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Describe the anatomy of capillaries.
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- single layer of epithelial cells
- tight or narrow junctions (most substances leave capillaries this way) - vesicles make up 35% of cytoplasm of endothelia (proteins, fluids move across cells in vesicles and through tight junctions) |
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What is the difference between the sol and gel state as it relates to tissue lymphatics?
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sol -- moving fluid
gel -- collagen, elastin fibers, ground substance (hyaluranon and other proteoglycan molecules) |
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What are tissue channels?
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- space where fluid can move through tissues
- continuous network of passages - drain into initial lymphatics - act as 'pre-lymph' vessels in areas there are none (brain, retina) |
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What is TTP? COP?
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TTP: total tissue pressure changes
COP: colloidal osmotic (oncotic) pressure |
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What is hydrostatic pressure (as it relates to fluid movement through tissue channels)?
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movement from high to low
- in most tissue channels, THP (tissue hydrostatic pressure) is negative, -3 to -5 mmHg - THP is higher at organs and during edema |
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Why is THP higher at organs and during edema?
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natural safety factor to slow the movement of fluid
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TTP is the sum of _______.
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gel and sol pressures
- can be influenced by external factors (increased fluid in tissues, movement, peristalsis, skin stretch...) |
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What is COP?
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ability of protein molecules to draw fluid from areas where they are in greater concentration to areas of lesser concentration
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What are macrophage functions? (4)
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- lyse proteins and other waste debris
- store particles that cannot be broken down - carry antigens to lymph nodes to alert immune cells - help destroy antigens |
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how do macrophages help fluid move through tissues?
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break down proteins in tissues (proteolysis) so fluid can move more easily through channels to be returned to circulatory system
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where do macrophages originate?
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- originate in bone marrow
- travel in blood as MONOCYTES - some are lodged in lymph nodes, majority are found in interstitium |
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where are initial lymphatics found?
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just under the skin forming a mesh
-near capillaries - have small finger-like projections |
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What is a precollector?
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intermediate structure, takes fluid on to deeper structures from initial lymphatics
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What is the function of initial lymphatics?
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to pick up fluid and plasma proteins that leak out of capillaries to the tissues (ultrafiltration)
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How does fluid enter the initial lymphatics?
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1. changes in TTP
2. the flaps of the initial lymphatics open 3. fluid enters **fluid enters initial lymphatics when TTP is LOW (not high as one might think) |
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What is the histology/anatomy of initial lymphatics?
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- like venous end of capillaries (single layer of endothelial cells
- many openable junctions made of overlapping endothelial cells - myofibrils connect endothelial cells to the elastin in the CT |
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what is a lymphangion?
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functional unit of lymph vessels that lies between semilunar valves
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What is TTP power?
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** fluid enters initial lymphatics when TTP is LOW
**fluid moves on to collectors when TTP is HIGH also powered by inc pressure of fluids in tissues (THP) -- inc THP holds flaps of initial vessels open and more fluid will enter |
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What makes lymphatic fluid flow along?
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the fluid flows from high pressure to low pressure, causes the lymphatics to move along
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What are 2 fluid exchange mechanisms?
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1. permeability (diffusion)
2. pressures |
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How does permeability affect fluid exchange mechanisms? (discuss in relation to gas, lipid solubles, water, ions, and small molecules)
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- gas/soluble substances dissolve and diffuse
- water/ions/small molecules dissolve through walls, close junctions, fenestrae (small pores in endothelial cells), vesicles |
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How does permeability affect fluid exchange mechanisms? (discuss in relation to large molecules)
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large molecules leave through fenestrae and open junctions
- main avenue is through vesicles - affected by pore size and electrical charge |
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What are the 2 parts of Starling's Forces?
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1. hydrostatic pressure:: pressure PUSHING fluid away (shoving match)
2. colloidal osmotic/oncotic pressure:: pressure PULLING fluid toward (tug of war) |
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What is BHP/THP?
What is BCOP/TCOP? |
BHP: blood hydrostatic pressure
THP: tissue hydrostatic pressure ** hydrostatic pressure (pressure pushing fluid way, a shoving match) BCOP: blood colloidal osmotic/oncotic pressure TCOP: tissue colloidal osmotic/oncotic pressure ** colloidal osmotic/oncotic pressure:: pressure pulling fluid toward, a tug of war |
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What does the filtration permeability coefficient Kf say about the permeability of the vessel walls?
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the more permeable the vessels are, the larger the coefficient
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What does the reflection coefficient (sigma) say about the size of the pores?
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- values range from 0-1
- as pore size decreases, sigma becomes larger - at 1, no pore exists and no protein molecules can get out - at 0, all proteins travel freely - average is 0.7 (makes it harder for proteins to get back into the venous system) |
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What is Starling's Equation?
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net fluid flow = Kf (BHP - THP) - sigma (BCOP - TCOP)
(BHP - THP): effective ultrafiltration rate (BCOP - TCOP): effective reabsorption rate ** to maintain equilibrium, lymph uptake must equal the net fluid flow. Net fluid flow is affected by proteolysis. |
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Describe ultrafiltration.
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1. at the arterial end of the capillary, the BHP is high
2. in tissues the THP is low (negative) 3. fluid is pushed out into the tissues = ultrafiltration 4. venous end of the capillary, the BHP has decreased 5. plasma proteins (BCOP) hold onto remaining fluid 6. ultrafiltration ends |
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What happens during ultrafiltration?
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- in tissues, the THP starts out low
- the THP starts to rise as the fluid comes from the capillaries slowing ultrafiltration and increases the uptake by the lymphatic system - proteins are slowly leaking out the capillaries (via vesicles) |
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______ carry out proteolysis.
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macrophages (monocytes in the bloodstream)
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TRUE or FALSE:
Proteins can get back into the capillaries at the same rate at which they leave. |
FALSE. They can't get in at the same rate.
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During reabsorption what is the relationship between the BCOP and BHP at the arterial and venous ends?
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arterial: BHP>BCOP
venous: BCOP > BHP - the THP has risen (d/t blood flowing into the tissues) - some fluid from tissues is pulled back in at the venous end of the capillaries = reabsorption |
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Describe reabsorption vs. lymphatic uptake.
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reabsorption at the venous end of the capillary is transient
most excess fluid from tissues is absorbed by the lymphatics |
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Which is the primary remover of fluid...the lymphatic system or the venous system? implications?
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the lymphatic system isn't a backup to the venous system- it is the main remover of fluid from tissues in cases of increased fluid
venous end of capillaries reabsorbs small amount of excess, a back up for the lymph system |
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What are 3 safety measures in place for if Starling's forces get disrupted?
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1. increased fluid in tissue leads to decreased ultrafiltration, increase in reabsorption, increased lymph flow
2. decreased concentration of proteins allow more absorption 3. macrophages break down proteins leading to more reabsorption and less ultrafiltration |
