Test II Flashcards
What is the main function of systemic circulation?
To deliver adequate oxygen and nutrients to the systemic tissues and remove carbon dioxide & other waste products from the systemic tissues
What conduit does the system circulation serve as?
For transport of hormones, and other substances and allows these substances to potentially act at a distant site from their production
What are the functional parts of circulation?
Systemic arteries, Arterioles & Pre-capillary sphincters, Capillaries, Venules & Systemic Veins
What is the function of system arteries in circulation?
Designed to carry blood under high pressure out to the tissue beds
What is the function of arterioles & pre-capillary sphincters?
Act as control valves to regulate flow
What is the function of capillaries?
Exchange between tissue (cells) & blood
What is the function of venules?
Collect blood from capillaries
What is the function of systemic veins?
Return blood to heart/dynamic storage.
What are the 3 basic theories of circulatory function?
1) Blood flow is proportional to metabolic demand 2) Cardiac output is controlled by local tissue flow 3) Arterial pressure control is independent of local flow or cardiac output
What is the definition of flow (F)?
The volume of blood that passes a certain point per unit of time
In the formula F = ΔP/R, flow is directly proportional to _____ and inversely proportional to _____?
ΔP [Pressure gradient (P1 - P2)]; R (resistance)
The formula F = ΔP/R is known as?
Ohm’s Law
What is the driving force of blood?
Pressure Gradient
What is proportional to flow (F)?
Pressure Gradient
The difference in pressure between two points (P1-P2) is know as?
Pressure Gradient
At any give F, the greater the drop in P in a segment or compartment, the greater the __________ to flow.
Resistance
Where does the greatest resistance to flow occur?
The pre-capillary resistance vessels (arterioles, metarterioles, precapillary sphinters)
Systemic circulation is predominately what type of circuit?
Parallel
What are the advantages of parallel circuitry?
1) independence of local flow 2) minimizes total peripheral resistance (TPR) 3) Oxygen rich blood supply to every tissue
The total vascular resistance (TVR) is equal to the sum of the total _________ resistance plus the total _________ resistance.
Pulmonic; peripheral
Internal friction of a fluid associated with the intermolecular attraction is know as?
Viscosity
Blood is a suspension with a viscosity of ______, with most of viscosity due to RBC’s
3
Plasma has a viscosity of ___?
1.5
Water is the standard with a viscosity of ____ ?
1
What increases the flexibility of RBC’s?
Fibrinogen
When velocity decreases whay increases?
Viscosity
Why does viscosity increase when velocity decreases?
Elements in the blood sticking together
Cells momentarily getting stuck at constriction points can increase __________ _____________?
Apparent viscosity
What can decrease viscosity?
Small vessel cells lining up
What are the components of vessels
Endothelium, elastic tissue, smooth muscle, fibrous tissue
What is the relative composition of the aorta
Elastic tissue>Fibrous Tissue>Smooth muscle
What is the relative composition of a typical artery?
Smooth muscle>Elastic tissue >Fibrous Tissue
What is the relative composition of veins?
Elastic Tissue = Smooth muscle = Fibrous tissue
What is the relative composition of capillaries?
Endothelium only
What is Hematocrit?
The volume percentage of red blood cells in the blood. AKA packed cell volume
What is the normal range of hematocrit?
38%-45%
Is Laminar or Turbulent Flow streamlined?
Laminar
Is Laminar or Turbulent Flow normal?
Laminar
Does Laminar or Turbulent Flow have vibrational noise?
Turbulent
Is Laminar or Turbulent Flow have a narrow band?
Laminar
Is Laminar or Turbulent Flow least efficient?
Turbulent
Is Laminar or Turbulent Flow frequently associated with vessel disease (bruit)?
Turbulent
Is Laminar or Turbulent Flow have a broad band?
Turbulent
Is Laminar or Turbulent Flow silent?
Laminar
Is Laminar or Turbulent Flow most efficient?
Laminar
Is Laminar or Turbulent Flow cross mixing?
Turbulent
What can give the probability statement for turbulent flow?
Reynold’s Number
R# = vDρη or Re = vdρ/η is known as:
Reynold’s Number
In Reynold’s number, the greater the R#, the greater the _________
Probability for turbulence
In Reynold’s number v =?
Velocity
In Reynold’s number d =?
Tube diameter
In Reynold’s number ρ =?
Density
In Reynold’s number η =?
Viscosity
In Reynold’s number, if R#
Laminar
In Reynold’s number, if R#
Turbulent
What type of flow-meter uses ultrasound to determine velocity of flow?
Doppler Ultrasonic Flow-meter
What is the Doppler frequency shift?
As RBC’s move toward the transmitter, sound waves are compressed increasing the frequency of the returning waves
What two methods are used to determine cardiac output?
Fick principal and indicator dilution
What methods are used to determine vessel flow?
Venous occlusion plesthymography, Doppler ultrasonic flowmeter and Vascular flow cuffs
PBF (pulmonary blood flow) = O2 uptake/AV (arteriovenous O2) difference is the formula for?
Fick Principal
Which method for measuring cardiac output is the gold standard and used more often clinically?
Indicator dilution
What method for measuring cardiac output is based on conservation of mass?
Indicator dilution
In the indicator dilution method for measuring cardiac output, cardiac output is approximately equal to what?
the average duration of the curve (dye concentration)
What is distensibility?
the ability of a vessel to stretch (distend)
In the vascular system, are all blood vessels distensible?
Yes
Which vessels are the most distensible?
Veins
What is compliance?
The ability of a vessel to stretch and hold volume?
Which vessels are the most complient?
Veins
Is compliance equal to distensibility?
No
Is compliance proportional to distensibility?
Yes
What will the following formula give you?
Δ Vol/ΔPressure x Initial Vol
Distensibility
Vascular Distensibility = Increase involume/Increase in pressure x Original volume
What will the following formula give you?
Δ Vol/Δ Pressure
Compliance
Vascular Compliance = Increase in volume/Increase in pressure
What will the following formula give you?
Distensibility x Initial Volume
Compliance
Compliance is equal to distensibility times volume
