Lymphedema Part 1- Background Flashcards
Normal fluid lvls:
How maintained?
Balance bw hydrostatic and osmotic pressure inside and outside of blood vessels
Hydrostatic pressure:
force generated by the pressure of fluid w/in or outside of capillary on the capillary wall
Osmotic pressure:
Colloid osmotic pressure or “oncotic pressure”→ pressure exerted by PROs, notably albumin, inside or outside of a vessel that tends to pull water towards the PROs
Hydrostatic Pressure and Osmotic Pressure
Work OPPOSITE one another!
When balanced, NORMAL fluid lvls exist and edema does NOT exist
Balance bw hydrostatic and osmotic pressure inside and outside of blood vessels maintained by the blood capillary fluid exchange
via 4 mechanisms:
- Diffusion
- Osmosis
- Filtration
- Reabsorption
Blood Capillary Fluid Exchange
Diffusion
Mvmt of mc’s and particles from areas of HIGH concentration to LOW concentration
Equalizes their distribution*
Blood Capillary Fluid Exchange
Osmosis
- Mvmt or diffusion of water from area of HIGH water concentration to area of LOW water concentration across semipermeable or permeable memb.
- memb only permeable to H2O
- Osmotic or oncotic pressure
Blood Capillary Fluid Exchange
Filtration & Reabsorption
Passive exchange of water and micromc’s across memb
Pressure gradient caused by blood cap. pressure (BCP)
Mvmt occurs HIGHER to LOWER pressure areas
-
Filtration:
- water filters thru capillary memb into interstitium
- carries nutrients TO tissue
- water filters thru capillary memb into interstitium
-
Reabsorption
- water reabsorbs thru capillary memb in to circulatory system
- carries waste products FROM tissue
- water reabsorbs thru capillary memb in to circulatory system
Blood Capillary Fluid Exchange
Incd Blood Cap pressure vs. Incd Tissue pressure
- Incd blood cap. pressure→ results in an INC in net filtration; more water filtering TO tissue
- Incd tissue pressure→ results in INC in net reabsorption; more water moves BACK INTO circulatory system
Where does Lymphatic System fit in?
Normally…..
- 10% ECF returned to circ. system thru lymphatic vessels
- 90% reabsorbed by venous caps.
- MAJORITY of extracell. PROs transported by lymphatic system
- PROs and waste prods too lg to be reabsorbed by venous caps.
Lymphatic System:
- Lymphatic vessels, nodes, other tissues
- CLOSE prox. to the circ vessels and exist in all areas & parts of body
- Divided into superf and deep; separated by fascia
- Redundancy + back up systems in order to maint. function in presence of injury or illness
Lymph Fluid
Once its in lymphatic system, call in LYMPH!
- ALL fluid, once in lymph. system==> LYMPH!
- Components of Lymph Fluid:
- Water
- PRO
- Cellular components & particles
- Fat and Fatty acids
Lymphatic Vessels
Smallest → Largest
- Lymph caps→ Lymph precollectors→ Lymph collectors→ Lymphatic trunks→ Lymphatic ducts
Lymph Capillaries
- Initial lymph vessels
- Close prox. w/ venous caps
- Cover surf of entire body
- Closed/dead-end tubes
- Flat endothelial cells
- “swinging flaps”→ allow lg mc’s to enter from interstitium
Lymph Caps
MORE
- Anchoring filaments
- absorb macromc’s (PRO, debris)
-
NO one-way valves inside vessels
- Lymph fluid can move in either direction w/in lymph caps**** KNOW THIS!
- Flow of lymph fluid thru lymph caps→ negative pressure “suction”
-
External pressure exerted on surrounding tissue:
- Respiration, MM contraction, massage, mvmt, compression garments/bandaging, gravity
-
External pressure exerted on surrounding tissue:
Lymph Caps vs. Blood Caps
See chart
Lymph Caps vs. Blood Caps.
-
Lymph Caps.
- Larger in diameter, Lumen is irregular, More permeable, NOT connected to venous or arterial vessels, but closed/dead-end tubes
- Fluid can flow into the lymph cap, but not OUT into interstitial space
- Purpose is to carry waste OUT of tissue
- Flow of lymph fluid thru lymph caps:
- Negative pressure “suction” created when more proximal lymph vessels emptied
- Ext. pressure from surrounding tissue
Lymph Caps. vs. Blood Caps.
-
Blood Caps:
- SMALLER in diameter, Lumen more regular, LESS permeable,
- ARE connected to arterial vessels in the interstitium ==> continous flow
- Fluid can flow INTO and OUT of capillary
- Purpose is to carry nutrients TO tissue and water OUT of tissue
- Flow of blood thru caps is facilitated by:
- pumping of the heart as well as mm contraction***
Lymph PREcollectors
Connect superf lymph caps to deeper lymph collectors*
*may contain valves
Lymph Collectors
- Transport fluid to lymph trunks and nodes
- Innervated by SNS
Lymph Collectors
MORE
- Contain valves
- One-way transport of fluid proximally*
-
Lymphangiomotoricity=> incd rate and quantity of lymph fluid transport from interstitium back into circ. system
-
INCs when:
- Incd lymph formation
- Ext manual stretch on lymph wall
- Manual Lymphatic drainage
- INCd temp
- INCd mm activity
- Diaphragmatic breathing
- Pulsation of adj. arteries
- Hormonal inc’s
-
INCs when:
Lymphatic Trunks
- Transport lymph FROM collectors TO lymphatic ducts
-
Lumbar trunks: L and R
- Drains LEs, lower body quadrants, ext. genitalia
-
Supraclavicular trunk
- B/L→ drains head, neck, shoulder, part of mammary gland
-
Subclavian Trunk
-
B/L→ Drains lymph from axillary lymph nodess
- UEs, shoulder, anterio/posterior upper quarter, majority of mammary gland
-
B/L→ Drains lymph from axillary lymph nodess
Lymphatic Trunks
2 more
-
Parasternal Trunk
-
B/L→ Drains parasternal lymph nodes
- Part of mammary gland, pleura, diaphragm, liver, pericardium, chests, abdom areas
-
B/L→ Drains parasternal lymph nodes
-
Jugular Trunk
- B/L→ Drains head/neck regions
Lymphatic Ducts
2:
-
Thoracic Duct:
- Cisterna Chyli
- Ends @ L venous angle
- L internal jugular and left subclavian arteries
- Valve @ junction→ prevents blood from entering lymphatic system
- largest lymph vessel in body
- ~3L lymph/day
-
Right Lymphatic Duct
- formed where R jugular, supraclavicular, subclavian, and parasternal trunks meet
-
Empties→ R venous angle
- ¼ of total lymph/day
Lymph Nodes
-
Function:
- Protect body by acting as filter for harmful mats such as pathogens, cx cells, dust, dirt
- Produce antibodies (antigen stimulated lymphocytes)
- Thicken lymph fluid by reabsorbing water
Fluid usually passes thru several nodes w/in chain to insure suff. filtration
Lymph Nodes
- Lymph fluid flows slowly inside nodes→ lymphocytes/macrophages time to ID pathogens and debris
- Fluid reabsorbed partly by blood venous caps, remaining lymph transported out of nodes
-
Nodes often first defense in lymphatic transport
- Sentinel nodes→ first to drain region of body
- Sentinel Node biopsy→ performed for most Cx’s to detect spread of cx cells*
Lymphatic Watersheds
Linear areas that separate body regions that are drained by same vessels
*a few lymphatic vessels cross watersheds→ “anastomoses”
VIDEOS!!!!
SLIDE 28
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