Term
| where is the majority of the blood volume? |
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Definition
in the veins (70%)
predominantly small veins and venules |
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Term
| how much blood is in the body? |
|
Definition
| about 5 liters, 7.5% body weight |
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Term
| how do flow, velocity, and cross sectional area relate? |
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Definition
flow = velocity x cross sectional area
as one goes up the other goes down |
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Term
| what is poiseuille's law and how does it relate to flow? |
|
Definition
relates the radius and length of a tube to flow
flow = radius ^ 4
double the radius, increase flow by 16 x's
flow = 1 / length
double the length, decrease flow by half |
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Term
| how does pressure affect flow? |
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Definition
| the greater the pressure the greater the flow |
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Term
| how does viscosity affect flow and sheer stress? |
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Definition
the greater the viscosity the less the flow
and the greater sheer stress |
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Term
| what affect does laminar flow have on tube diameter and flow velocity? |
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Definition
| the greater the diameter the greater the flow velocity |
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Term
| describe the difference between laminar and turbulent flow. |
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Definition
| laminar flow involves a liquid flowing in sheets through a tube, whereas turbulent flow involves a liquid moving sporadically |
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Term
| what properties contribute to turbulent flow? |
|
Definition
higher fluid density
larger vessel diameter
higher mean velocity
low viscosity |
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Term
| what properties contribute to laminar flow? |
|
Definition
low fluid density
small vessel diameter
low mean velocity
high viscosity |
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Term
| true or false, turbulent flow contributes to greater arterial pressure? |
|
Definition
|
|
Term
| what are some causes of turbulent flow? |
|
Definition
high velocity
local obstruction
abrupt increase in caliber
obstruction plus increased caliber
branching |
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Term
| how is resistance in series calculated? |
|
Definition
| the resistance of each region is added together |
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Term
| how is resistance in parallel calculated? |
|
Definition
| the sum of the reciprocal resistances |
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Term
| what determines the wall tension in a tube? |
|
Definition
the diameter
the higher the diameter the greater the wall tension |
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Term
| define transmural pressure. |
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Definition
| the difference between internal and external pressure of a vessel |
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Term
|
Definition
defines vascular wall tension as the transmural pressure x's the radius
T = P x r |
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