Microcirculation Flashcards
How do tissues control their own blood flow
by changing the diameter of the arterioles
What kind of cells do capillaries have
endothelial cells
What are the four components of the microcirculation and capillary system
Arterioles
Metarterioles
precapillary sphincters &
venules
Which component of microcirculation has smooth muscle fibers at intermittent point
Metarateriole
4 characteristics of the structure of a capillary wall
A single layer of endothelial cells
A thin basement membrane (0.5 micrometer
Internal diameter = 4.9 micrometer
Slit pores (intercellular clefts)
From largest to small size pores, rank the following:
GIT, liver, brain
brain, GIT, liver
What is the shape of Glomerular capillaries of the kidney
small oval windows called fenestrae
which molecules has the largest molecular size and which one has the least
albumin (biggest) and water (smallest)
What are the components of the Interstitium
Free fluid vesicles
rivulets of free fluid
proteoglycan filaments
collagen fiber bundles
What is Starling Equation
Jv=Kf [(Pc−Pi) − (πc−πi)]
What can the filtration coefficient help to determine
the filtration coefficient can be used to determine the relative number of open capillaries
What is the total quantity of lymph per day
2-3 L
What is usually the protein concentration in the thoracic duct
3-5g/dl
Most of the protein in lymph found in the thoracic duct was absorbed from which organs
liver and kidney
is lymph flow directly or inversely proportional to interstitial fluid pressure
directly proportional
What are 4 factors that increase interstitial fluid pressure
Elevated capillary pressure
Decreased plasma colloid osmotic pressure
Increased interstitial fluid colloid osmotic pressure
Increased permeability of the capillary
The thoracic duct can generate pressure as much as ___ to ____ mmHg
50 to 100
External factors causing pumping of lymph
Contraction of the surrounding skeletal muscles
Movements of the parts of the body
During period of rest flow is sluggish
Pulsations of arteries adjacent to the lymphatics
Compression of tissues by objects outside the body
Two main factors that determine lymph flow
Interstitial fluid pressure (Pif ) x lymphatic Pump Activity
What are the steps involved in lymph controlling interstitial Fluid Protein Concentration, Volume, and Pressure
- Proteins leak
- Protein accumulates
- Increase in interstitial oncotic pressure
- increased fluid filtration from capillaries
- increased interstitial fluid volume and fluid pressure
- cause lymph flow
- lymph carries away excess interstitial volume and protein
- this balances the rate of leakage
What is the benefit of having a negative interstitial fluid pressure
Holds tissue together
What happens when tissue lose their negative pressure
Fluid accumulates in the spaces (edema)
Two importance of local control of blood flow response to tissue needs
Keep the workload on the heart minimum
Tissues may suffer from oxygen nutritional deficiency
What are the two broad terms for the mechanisms of blood flow control
Acute control
Long term control
