Exam II: 4A Edema and Microcirulation Flashcards
Explain the capillary network.
- Blood is supplied to each capillary network by arterioles
- Blood leaves the capillary network by draining into Venules
What is the major function of the capillary network?
Nutrient and waster exchange w/ tissues
Where is lymph drained?
Away form the tissues by the lymphatic\\ network
What is lymph?
A fluid that:
1) is created in the Interstitial spaces of tissues
2) Put back into the cirulation
How do we normally exchange things between the vasculature and interstitium?
1) Diffusion across endothelial cell membranes
2) Movement thru fenestrations
3) Transport via small vesicles (pinocytosis)
What is the Starling forces (pressures) ?
Fluid movement across clefts and fenestations
What is Pc, P i, Pi c, Pi i?
Pc= Capillary hydrostatic pressure
Pi= Interstitial hydrostatic pressure
Pi c= capillary oncotic(proteins) pressure
Pi i= intersitial oncotic(proteins) pressure
What do capillaries consist of?
Simple squamous epithelial cells
Where does Pc = capillary hydrostatic pressure (BP), moves things?
- It moves things OUT to the fenestrations (especially things that do not have a concentration gradient).
- They have to fit!
What are 4 things that can’t fit thru the fenestrations???
- RBC
- WBC
- platelets
- Big chunk proteins
What is the second force Pi c do? (capillary oncotic pressure)
Osmotic force created by proteins to force material IN.
On the arterial end which force (Pc or Pi c) is greater?
Pc is ! This is called FILTRATION!
-You will loose fluid in this capillary. (cell will have access to it)
What is the pathway for lymphatic vessels?
Lymphatic capillaries–>Lymphatic Venules & Veins–>Lymphatic Ducts(Right Lymphatic Duct & Thoracic Duct)
What does the thoracic ducts collect? And where is it located?
- Collects lymph from MOST of the body regions.
- It ascends into the root of the neck on the left side & opens into the Left subclavian vein near the junction of the left internal jugular vein.
Where does the right lymphatic duct receive lymph from ? And where does it empty?
- The right side of the head, neck, and trunk and from the right upper extremity.
- Empties into the right Subclavian vein.
What are lymph nodes?
- “beads” or “swellings” along certain lymphatic vessels.
- FILTERS
Where are lymph nodes most extensively found?
In the axillary, breast, neck, abdomen, thorax, pelvis, and groin.
What is EDEMA?
- Palpable swelling due to expansion of extracellular fluid
- 2 types: 1) pitting 2) non-pitting
- This can be seen when you press your finder into the skin, it is temporary depressed.
What happens to the excess fluid with Edema?
It becomes infiltrated with protein or other material so that it cannot move freely within the tissue spaces.
When does Edema occur?
When the volume of interstitial fluid exceeds the capacity of the lymphatics to return it to the circulation.
What is Edema caused by?
- Excess filtration (typically reflected by increase of Pc)
- Decreased absorption (typically reflected by decrease of Pi c)
- increased capillary permeability
- blocked lymphatics
On the venous side which force (Pc and Pi c) will be more dominate?
Pi c does! this is called ABSORPTION
Note:
Why? Pc goes down, why did the BP fall?
1) further away from the heart
2) LOSS of FLUID!!!
Why does “Pi c “ go up?
Concentration of protein (protein is too big!) is greater on the venous side
Why does Edema not happen?
B/c we take excess fluid, soak it up but they in lymph nodes and back into blood.
In regards to (Pi c), why would protein [ ] be low?
Protein [ ] low:
- Excreting it in the urine
- You are not enough protein
- No protein in the blood = Edema
- The liver processes the plasma protein
What causes Edema ?
- Elevation in Pc
- Drop in Pi c
- Increase permeability of capillaries
- lymphatic system backed up, because of infection? metastasis?
