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63 Cards in this Set

  • Front
  • Back
The Frank-Starling Mechanism
involves a _________ in myocardial fiber ______.
sustained change

lengths
increase Venous Return (Sustained)
leads to
Venous Return > Cardiac Output
Venous Return > Cardiac Output
leads to
Ventricular EDV and ESV (over several cardiac cycles)
Ventricular EDV and ESV (over several cardiac cycles)
leads to
Ventricular Myocardial Fiber Lengths (Preload)
Ventricular Myocardial Fiber Lengths (Preload)
leads to
increased Force of Myocardial Contraction
increased Force of Myocardial Contraction
leads to
increased Ventricular Pressure Development
increased Ventricular Pressure Development
leads to
increase in Ventricular Stroke Volume
increase in Ventricular Stroke Volume
leads to
increase in Cardiac Output to Equal increase Venous Return
(New Steady State)
Both EDV and ESV remain increased as long as ___is elevated.
VR
Equality of VR and ___ is restored, after a transient inequality
CO
Increased _____ ventricular CO increases VR to the ____ ventricle, resulting in a subsequent increase in ventricular CO by the same mechanisms outlined in diagram above.
right
left
left
Response to a sudden increase in total peripheral resistance (afterload). Assume constant venous return and HR:

increase TPR (sustained)
leads to
Ventricle initially unable to pump normal SV against the increased TPR
Ventricle initially unable to pump normal SV against the increased TPR
leads to
Initial decrease in SV and CO
Initial decrease in SV and CO
leads to
Venous Return > Cardiac Output
Venous Return > Cardiac Output
leads to
Increased ventricular EDV and ESV (over several cardiac cycles)
increased Ventricular EDV and ESV (over several cardiac cycles)
leads to
increased Ventricular Myocardial Fiber Lengths (Preload)
increased Ventricular Myocardial Fiber Lengths (Preload)
leads to
increased Force of Myocardial Contraction
increased Force of Myocardial Contraction
leads to
increased Ventricular Systolic Pressure Development
increased Ventricular Systolic Pressure Development
leads to
increased Ventricular Stroke Volume
increased Ventricular Stroke Volume
leads to
Cardiac Output to Equal Venous Return
(New Steady State)
Both EDV and ESV remain increased as long as ____ is elevated and VR is constant.
TPR
An increase in afterload results in an increase in _____, under the conditions specified above.
preload
The initial decrease in SV is reversed and CO = ___ once again.
VR
bradycardia (assume constant VR and TPR)
leads to
(Venous Return > Cardiac Output)

increased Diastolic Ventricular Filling Time
increased Diastolic Ventricular Filling Time
leads to
increased EDV and Myocardial Fiber Lengths (Preload)
increased EDV and Myocardial Fiber Lengths (Preload)
leads to
increased Ventricular Pressure Development and Stroke Volume
increased Ventricular Pressure Development and Stroke Volume
leads to
Cardiac Output to Equal Venous Return
(New Steady State)
Changes in EDV and fiber lengths are sustained as long as ___ change is sustained and VR and TPR are constant.
HR
Increased HR would result in the opposite responses due to _____ time for ventricular filling.
decreased
In normal humans, these mechanisms operate only transiently. Other control mechanisms normally help prevent large changes in ventricular volume. Large, rapid changes in ventricular volume are also normally prevented by an intact ________ .
pericardial sac
If extrinsic control mechanisms (see below) fail, or the pericardial sac is surgically opened, the ____________ relationship becomes more important.
Frank-Starling
However, even in normal hearts, the Frank-Starling mechanism is very important in continuously matching the output of one ventricle with the other as _______ and ________ fluctuate.
venous return
ventricular afterloads
The Frank-Starling relationship is not confined to a single ventricular performance vs. preload curve in each heart. That is, "families" of curves for each heart can be generated under different conditions. For example, infusion of norepinephrine shifts the curve upward and to the left due to the __________of this catecholamine.
positive inotropic effect
The relationship between LV stroke work and end diastolic pressure (Fig. 4-19) is one form of _________ and still is an expression of the basic Frank-Starling relationship, with cardiac fiber length depending on end diastolic volume and pressure.
"ventricular function curve"
The force of cardiac muscle contraction in the _______ is directly related to heart rate, within certain limits.
steady state
As the interval between beats decreases from 20 sec to 0.5 sec, _____ tension development progressively increases
steady state
The changes in steady state tension development occur despite constant diastolic fiber _____. (I.e., not a result of the Frank-Starling mechanism.)
length
Following an increase in heart rate, several contractions are required to reach a new steady state, and tension development _______ gradually ("treppe", i,e., a non-steady state; Fig. 4-21 A). The opposite responses occur following a decrease in heart rate, with a gradually decreasing tension for a few beats.
increases
The beat following a premature ventricular systole is delayed, but more forceful than normal. This may occur in the absence of any change in diastolic fiber length or EDV. (Contractions A, B and C in Fig. 4-23 are isovolumic and are not occurring during steady state conditions.)
Postextrasystolic potentiation
Postextrasystolic potentiation in an otherwise normal heart also involves an increase in ventricular filling and ____ during the pause after the premature beat. This and the volume-independent mechanism mentioned above both produce the increased _______ of the postextrasystolic beat.
EDV
pressure
Since rate-induced regulation involves a change in cardiac performance without a sustained change in diastolic cardiac fiber length, these responses involve changes in myocardial ______ or inotropic state.
contractility
Increases in cardiac performance at constant diastolic fiber lengths must ultimately result from increased availability of ____ ions to the contractile proteins, or changes in myofilament sensitivity to ____.
Ca2+
Ca2+
In sympathetic Cardiac Innvervation:
The right branches innervate primarily the ___ node and ____ atrial and ventricular muscle.
S-A
right
In sympathetic Cardiac Innvervation:
The left branches innervate primarily ___ node and ____ atrial and ventricular muscle. Overlap may occur.
AV
left
peak ventricular pressure, dP/dt max and rate of relaxation _______ .
increase
Effect of left sympathetic stimulation on left ventricular performance (right stimulation has less marked effect):
ventricular function curves shift __________;
upward to the left
Effect of left sympathetic stimulation on left ventricular performance (right stimulation has less marked effect): force-velocity curves shift _______
upward to the right,
Effect of left sympathetic stimulation on left ventricular performance (right stimulation has less marked effect): Vmax _______
increases
Effect of sympathetic stimulation on heart rate (chronotropy): Stimulation of _____ sympathetics has a marked cardioacceratory effect, since these fibers innervate the SA node. ____ sympathetics have less effect on heart rate.
right
Left
Sympathetic activation also increases action potential conduction velocity(_______ ).
(dromotropy
Neurotransmitter: _________ stimulates beta adrenergic receptors
Norepinephrine
Postextrasystolic potentiation in an otherwise normal heart also involves an increase in ventricular filling and ____ during the pause after the premature beat. This and the volume-independent mechanism mentioned above both produce the increased _______ of the postextrasystolic beat.
EDV
pressure
Since rate-induced regulation involves a change in cardiac performance without a sustained change in diastolic cardiac fiber length, these responses involve changes in myocardial ______ or inotropic state.
contractility
Increases in cardiac performance at constant diastolic fiber lengths must ultimately result from increased availability of ____ ions to the contractile proteins, or changes in myofilament sensitivity to ____.
Ca2+
Ca2+
In sympathetic Cardiac Innvervation:
The right branches innervate primarily the ___ node and ____ atrial and ventricular muscle.
S-A
right
In sympathetic Cardiac Innvervation:
The left branches innervate primarily ___ node and ____ atrial and ventricular muscle. Overlap may occur.
AV
left
peak ventricular pressure, dP/dt max and rate of relaxation _______ .
increase
Effect of left sympathetic stimulation on left ventricular performance (right stimulation has less marked effect):
ventricular function curves shift __________;
upward to the left
Effect of left sympathetic stimulation on left ventricular performance (right stimulation has less marked effect): force-velocity curves shift _______
upward to the right,
Effect of left sympathetic stimulation on left ventricular performance (right stimulation has less marked effect): Vmax _______
increases
Effect of sympathetic stimulation on heart rate (chronotropy): Stimulation of _____ sympathetics has a marked cardioacceratory effect, since these fibers innervate the SA node. ____ sympathetics have less effect on heart rate.
right
Left
Sympathetic activation also increases action potential conduction velocity(_______ ).
(dromotropy
Neurotransmitter: _________ stimulates beta adrenergic receptors
Norepinephrine