Ch. 5 Vascular Flashcards
Total fluid energy of the vascular system is made up of
potential and kinetic energy
Potential energy is
stored or resting energy
Kinetic energy is
energy of work or motion
Blood always moves from an area of _______ to an area of ______
high energy/pressure, low energy/pressure
The highest pressure in the vascular system occurs in the
left ventricle of the heart
What is the pressure of the left ventricle
120mmHg
The lowest pressure in the vascular system occurs in the
right atrium
What is the pressure of the right atrium
2-6mmHg
Hydrostatic pressure is related to the
weight of the column of blood within the vessels
Hydrostatic pressure is related to weight and
a reference point
What is Bernoulli Principle
If velocity increases, then pressure must decrease
When velocity decreases, what happens to pressure
it increases
Relationship between velocity and pressure
inversely related
What two things cause energy loss in the vascular system
inertia, viscosity
What causes energy loss from conversion of friction to heat
viscosity
What causes energy loss when blood is forced to change direction or velocity
inertia
Inertial velocities depend on the
density and velocity of blood flow
Property of a fluid that resists the force tending to cause fluid to flow (friction that exists between bordering layers of fluid)
viscosity
Describes the steady laminar flow of Newtonian fluids and defines the pressure/flow relationships in the vascular system
poiseuille law
What are the variables for poiseuille law
viscosity, vessel length, vessel radius
What has a significant impact on flow due to being raised to the fourth power
radius
Resistance of flow: ______ is equal to the _____ drop divided by _____
resistance, pressure, flow
Resistance can therefore be expressed as
condensed poiseuille law
In the circulatory system, the blood vessel _____ is virtually _____ and the blood _____ does not vary
length, constant, viscosity
Changes in resistance to flow are due to change in
vessel radius
In peripheral resistance, low resistance flow is
antegrade throughout the cardiac cycle
Vessels that supply organs have a blood flow that is
low resistance
In peripheral resistance, high resistance has _____ flow in _____, ______ in _______ with ______ flow later in diastole
forward, systole, “reflected wave”, early diastole, antegrage
High resistance has what flow in systole
forward
High resistance has what flow in early diastole
“reflected wave”
High resistance has what flow later in diastole
antegrade
Result of a high resistance anterior bed
reflected wave
Exercise produces ______, which ______ resistance
vasodilation, decreases
Exercise on average will
increase blood flow 3-5 times of resting flow
There is an increase in flow to meet
metabolic demands
As flow progresses through the vessel, flow in the CENTER streamlines
moves faster than the streamlines at the edges (parabolic flow)
Turbulence can be defined by
reynolds number
reynolds number and the likelihood of turbulence is _____ proportional to what 3 things
directly / velocity, density, radius
reynolds number and the likelihood of turbulence is INVERSELY proportional to
viscosity
Hemodynamics and effects of exercise are
increases blood flow to as least 3-5 times resting values in normal limbs / induces vasodilation
Poiseuille law describes the
steady laminar flow of newtonian fluids
Poiseuille law defines the
pressure/flow relationships in the vascular system
Reynolds number for laminar flow
1500
Reynolds number for turbulent flow
2000
Converts the pulsatile output of the heart to a steady flow through the capillaries
hydraulic filter
What are part of the nervous system’s control of peripheral blood flow (circulation)
potassium ions, hydrogen ions, carbon dioxide
In hemodynamics of disease, what accounts for most abnormal energy losses in the arterial system
stenoses
In hemodynamics of disease, what occurs at the entrance and exit of a stenosis
inertial energy losses
Where do most inertial energy losses occur and why
exit, turbulence
Critical stenosis has degree of narrowing at which pressure and flow begin to
decrease
Critical stenosis typically occurs when _____ area has been _____ by _____
cross-sectional area, reduced, 75%
Critical stenosis has diameter reduction of
50%
In critical stenosis, a _____ in the length of a stenosis results in _____ increase in ______ across the stenosis
doubling, two-fold, energy losses
Collateral vessels are _______ that enlarge with a stenosis or occlusion
preexisting pathways
Collateral vessels help _____ at stenotic area, providing an alternative _____ for blood to reach _____ vascular bed
reduce resistance, pathway, distal
If a collateral vessel develops _____ to a stenosis, the collateral will _____ the total ______
parallel, lower, resistance
What 3 things will have little effect on collaterals
vasodilator drugs, exercise, sympathectomy
