B4-098 Cardiovascular Hemodynamics Flashcards
the heart provides a constant
pressure head
the goal of the cardiovascuar system is to maintain
mean arterial pressure
allows for perfusion
The cardiovascular system consists of two pumps arranged in
series
the systemic organs are arranged in
parallel circuits
allos same blood composition to each organ with independent flow
the systemic organs are arranged in
parallel circuits
allos same blood composition to each organ with independent flow
- high pressure
- left heart to organ systems
systemic circulation
- low pressure
- includes capillaries to right side of heart
pulmonary circulation
the pressure gradient amoung all organ systems
remains the same
differences in blood flow between organs are due to
differences in vascular resistance of each organ
portal special circulatory systems
3
- hepatic portal system
- renal portal system
- hypothalmic-pituitary portal system
main factors of hemodynamics
6
- blood flow
- resistance
- viscosity
- blood velocity
- blood pressure
- compliance
driven by a difference in pressure and opposed by the resistance of the vessels
blood flow
displacement of fluid per unit time
blood flow
amount of blood delivered by the heart into circulation
cardiac output
cardiac output during a single heartbeat
stroke volume
CO=
SV * HR
at rest, cardiac output for an individual is about
5 L/min
cardiac output can be increased by
increasing stroke volume or heart rate
factors that increase stroke volume
- preload: filling of the ventricle
- inotropic state: force of contraction
factors that decrease stroke volume
afterload: resistance to ejection of blood
blockage
factors that alter heart rate
- heart’s pacemaker activity
- extrinsic factors
measures the sound reflected by RBCs in movement
ultrasound
measures the change in electromagnetic force exerted by the moving blood in an electrial field
electromagnetic
involves the use of radioactive microspheres, injected on a vessel and collected downstream
reference sample method
measures regional blood flow
Implications of Poiseulle’s Law
Flow is […] proportional to the pressure difference between 2 points
directly
Implications of Poiseulle’s Law
Flow is […] proportional to the fourth power of the vessel radius
inversely
Implications of Poiseulle’s Law
Flow is […] proportional to the viscosity of blood
inversely
Implications of Poiseulle’s Law
Flow is […] proportional to the length of the vessel
inversely
if a vessel radius decreases by a factor of 2, resistance increases by a factor of
16
to the fourth power
inversely proportional to vessel radius to the fourth power
resistance
changes in the radius of arterioles are the major influences on
TPR
blood viscosity is determined by
hematocrit
erythrocyte concentration
two factors that affect resistance
- vascular radius
- blood viscosity
- site of greatest vascular resistance
- major component of TPR
arterioles
arteriolar dilation or constriction will affect the
TPR
expresses degress of slipperiness between layers
viscosity
organized in concentric layers of fluid moving down the length of a vessel
laminar flow
when flow become disorganized it is called
turbulent flow
factors that determine if flow is laminar:
- blood velocity
- blood viscosity
critical velocity
when flow changes from laminar to turbulent
- measure of velocity and viscosity
- increases when blood reaches critical velocity
reynolds number
in anemia, viscosity is
decreased
in polycythemia vera, viscosity is
increased
turbulent flow in the heart creates
murmurs
turbulent flow in the vessels creates
bruits
intense turbulence may be detected as mechanical vibrations
thrills