Function of the Heart Flashcards
Barbara Herlihy. (2020). The Human Body in Health and Illness (7th Edition) [Texidium version]. Retrieved from http://texidium.com
What are the event sequences occurring during one heartbeat?
(Herlihy, 2020, p. 326)
Cardiac Cycle
(Herlihy, 2020, p. 326)
What is a coordinated contraction and relaxation of the heart’s chambers?
(Herlihy, 2020, p. 326)
Cardiac Cycle
(Herlihy, 2020, p. 326)
What is heart muscle (myocardium) contraction?
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Systole
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Heart muscle contraction pumps blood out of a chamber during ___.
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Systole
(Herlihy, 2020, p. 326)
What is myocardium relaxation?
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Diastole
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When does blood fill a chamber?
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Diastole
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Atrial and ventricular muscle activity is closely coordinated.
For example, during ___ ___, the ventricles are in diastole.
In this way, when the ___ ___, they pump blood into the relaxed ventricles.
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atrial systole
atria, contract
(Herlihy, 2020, p. 326)
What are the three cardiac cycle stages?
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Atrial Systole
Ventricular Systole
Diastole
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The ___ contract (___) and pump blood into the ventricles.
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atria
systole
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Which stage includes open atrioventricular (AV) valves and relaxed ventricles?
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Atrial Systole
(Herlihy, 2020, p. 326)
Which stage includes the atrial systole’s end when the ventricles contract?
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Ventricular Systole
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As ventricular contractions begin, blood is forced against the ___ (___) valves, causing them to snap shut.
The blood pushes the ___ valves open, allowing blood to flow into the pulmonary trunk and aorta.
(Herlihy, 2020, p. 326)
atrioventricular (AV)
semilunar
(Herlihy, 2020, p. 326)
Which stage includes both the atria and ventricles for a brief period?
(Herlihy, 2020, p. 326)
Diastole
(Herlihy, 2020, p. 326)
Which stage includes blood flowing into the atria as the chambers relax?
(Herlihy, 2020, p. 326)
Diastole
(Herlihy, 2020, p. 326)
Which stage includes blood flowing passively into the ventricles because the atrioventricular (AV) valves are open?
(Herlihy, 2020, p. 327)
Diastole
(Herlihy, 2020, p. 327)
What is the blood filling stage?
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Diastole
(Herlihy, 2020, p. 327)
What follows diastole?
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Atrial Systole
(Herlihy, 2020, p. 327)
With a heart rate (HR) of 70 beats/min, the duration of the cardiac cycle is ___ seconds.
All chambers rest for ___ seconds.
(Herlihy, 2020, p. 327)
0.8
0.4
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As heart rate (HR) increases, the duration of the cardiac cycle (shortens/lengthens).
(Herlihy, 2020, p. 327)
shortens
(Herlihy, 2020, p. 327)
With a dramatic increase in heart rate (HR), the rest period (___) may shorten so much that cardiac function diminishes.
(Herlihy, 2020, p. 327)
diastole
(Herlihy, 2020, p. 327)
An episode of ___ may be accompanied by chest pain.
First, because of a decreased filling time, the blood amount that enters the ventricles decreases so less blood is pumped.
Second, because ___ blood flow to the myocardium occurs during ___, the diminished ___ period decreases ___ blood flow.
Decreased ___ blood flow, in turn, results in poor oxygenation of the myocardium and hence pain.
(Herlihy, 2020, p. 327)
tachycardia
coronary, diastole x 2, coronary
coronary
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Cardiac Cycle Stages
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(Herlihy, 2020, p. 327)
Which system plays an important role in coordinating and adapting cardiac function?
(Herlihy, 2020, p. 327)
Autonomic Nervous System (ANS)
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Specialized cardiac tissue displays automaticity and rhythmicity.
The electrical signal, the ___ ___, arises within the sinoatrial (SA) node and then spreads throughout the heart, causing the heart muscle to contract.
The heart initiates its own ___ ___.
(Herlihy, 2020, p. 327)
cardiac impulse x 2
(Herlihy, 2020, p. 327)
Which system affects cardiac impulse firing rate and travelling speed throughout the heart although it does not cause cardiac impulses?
(Herlihy, 2020, p. 327)
Autonomic Nervous System (ANS)
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Which system can make the heart muscle contract more forcefully; thus changing the heart’s pumping activity?
(Herlihy, 2020, p. 327)
Autonomic Nervous System (ANS)
(Herlihy, 2020, p. 327)
Which system includes the heart responing to an increased oxygen need by autonomically (automatically) beating faster and stronger when a person suddenly sprints down the street?
(Herlihy, 2020, p. 327)
Autonomic Nervous System (ANS)
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What are the two autonomic nervous system (ANS) branches?
(Herlihy, 2020, p. 327)
Sympathetic
Parasympathetic
(Herlihy, 2020, p. 327)
Which nerves supply the sinoatrial (SA) node, atrioventricular (AV) node, and ventricular myocardium (the sarcomere represents heart muscle)?
(Herlihy, 2020, pp. 327, 328)
Sympathetic
(Herlihy, 2020, pp. 327, 328)
What are the parasympathetic nerves also called?
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Vagus Nerves
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What innervates the sinoatrial (SA) node and atrioventricular (AV) node?
(Herlihy, 2020, p. 328)
Vagus Nerves
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Where is there no parasympathetic or vagal innervation?
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Ventricular Myocardium
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Which stimulation increases sinoatrial (SA) node activity, thereby increasing heart rate (HR)?
(Herlihy, 2020, p. 328)
Sympathetic
(Herlihy, 2020, p. 328)
Which stimulation increases the cardiac impulse travel speed from the sinoatrial (SA) node throughout the atrialventricular node (AV) and His-Purkinje system?
(Herlihy, 2020, p. 328)
Sympathetic
(Herlihy, 2020, p. 328)
Which stimulation increases myocardial contraction force?
(Herlihy, 2020, p. 328)
Sympathetic
(Herlihy, 2020, p. 328)
There are four clinically important points regarding excess sympathetic activity on the heart and blood vessels:
- Excess sympathetic activity produces the “___-or-___” response.
- Excess sympathetic activity plays a key role in some ___ states.
- Excess sympathetic activity often causes ___ (“fast” rhythm disorders).
- ___ resemble or block the effects of sympathetic activity.
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Fight-or-Flight
disease
tachydysrhythmias
Drugs
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Which response’s symptoms (racing and pounding heart) are found in anxious people, such as during panic attacks?
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Fight-or-Flight
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Which response’s symptoms are frightening, and the person is convinced of an impending heart attack?
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Fight-or-Flight
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Many trips to the emergency room (ER) are ___ related.
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panic
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Most circulatory shock signs and symptoms are caused by excess ___ firing.
(Herlihy, 2020, p. 328)
sympathetic
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The progressive deterioration of patients with heart failure is in large measure caused by persistent ___ nerve stimulation.
(Herlihy, 2020, p. 328)
sympathetic
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Some of the drugs used to treat heart failure are aimed at minimizing the sympathetic effects.
For example, ___ (Adrenalin) and dopamine increase heart rate (HR) and myocardial contractile force; i.e., they exert a sympathomimetic effect.
Drugs that block the sympathetic effects, include beta- and alpha-___ blockers.
(Herlihy, 2020, p. 328)
epinephrine
adrenergic
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Which stimulation decreases sinoatrial (SA) node activity, thereby decreasing heart rate (HR)?
(Herlihy, 2020, p. 328)
Parasympathetic
Vagus Nerve
(Herlihy, 2020, p. 328)
In the resting heart, ___ ___ is more intense than sympathetic activity.
For example, the sinoatrial (SA) node would like to fire at a rate of 90 beats/min.
However, the “braking” or inhibiting effect of the ___ nerve slows sinoatrial (SA) node firing to a rate of ___ beats/min, the normal resting heart rate (HR).
Without ___ ___, the heart (HR) would increase to 90 beats/min.
(Herlihy, 2020, pp. 328, 329)
vagal tone
72
vagus
vagal tone
(Herlihy, 2020, pp. 328, 329)
Which stimulation decreases cardiac impulse travel speed from the sinoatrial (SA) node to and through the atrialventricular node (AV) into the His-Purkinje system?
(Herlihy, 2020, p. 329)
Parasympathetic
Vagus Nerve
(Herlihy, 2020, p. 329)
No ___ (___) fibers innervate the ventricular myocardium and therefore they exert no effect on myocardial contraction strength.
(Herlihy, 2020, p. 329)
parasympathetic (vagal)
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There are two clinically important points about parasympathetic (vagal) nervous system activity:
- Certain conditions (heart attack) and drugs (digoxin) can lead to excess vagal discharge, which causes ___ (<___ beats/min) and increases the tendency of the heart to develop life-threatening electrical rhythm disturbances.
- ___ alter the effects of vagal activity.
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bradycardia, 60
Drugs
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Excess ___ ___ slows the cardiac impulse conduction through the heart, causing heart block (a condition in which the signal has difficulty traveling from the atria to the ventricles).
(Herlihy, 2020, p. 329)
vagal discharge
(Herlihy, 2020, p. 329)
What are abnormally slow rhythms?
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Bradydysrhythmias
(Herlihy, 2020, p. 329)
Digoxin decreases heart (HR) and slows cardiac impulse travel speed from the atria to the ventricle.
Because the effects of digoxin “mimic” vagal stimulation, it is called a ___ drug.
A drug may also produce effects that are similar to an inhibition of vagal discharge.
For example, atropine is used to relieve bradycardia because it blocks the effects of vagal stimulation and increases heart rate (HR).
Because of its blocking effects on the vagus nerve, atropine is called a ___ drug.
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vagomimetic
vagolytic
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DELETE CARD
DELETE CARD
What two variables are required to understand how the heart alters pumping activity?
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Cardiac Output
Venous Return
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Which variable is the blood amount pumped by the ventricle in 1 minute?
(Herlihy, 2020, p. 329)
Cardiac Output
(Herlihy, 2020, p. 329)
What is normal cardiac output?
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5 L / min
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The entire ___ ___ is pumped through the heart every minute as the total ___ ___ is about 5 L (5000 mL).
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blood volume x 2
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Which vairable is the blood flow rate back to the heart?
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Venous Return
(Herlihy, 2020, p. 329)
What two factors determine cardiac output?
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Heart Rate (HR)
Stroke Volume
(Herlihy, 2020, p. 329)
What is the number of times the heart beats each minute?
(Herlihy, 2020, p. 329)
Heart Rate (HR)
(Herlihy, 2020, p. 329)
WhIch factor is caused by the rhythmic firing of the sinoatrial (SA) node, the pacemaker of the heart?
(Herlihy, 2020, p. 329)
Heart Rate (HR)
(Herlihy, 2020, p. 329)
The normal adult resting heart rate (HR) is between ___ and ___ beats/min, with an average of ___ beats/min.
(Herlihy, 2020, p. 329)
60, 100
72
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What three reasons cause different resting heart rates (HR)?
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Size
Gender
Age
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The larger the size, the (slower/faster) the heart rate (HR).
Generally
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slower
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Women have slightly (slower/faster) heart rates (HR) than men.
Generallly
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faster
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The younger the person, the (slower/faster) the heart rate (HR).
Generally
(Herlihy, 2020, p. 329)
faster
(Herlihy, 2020, p. 329)
The normal adult heart rate (HR), for example, is ___ to ___ beats/min, whereas a normal child’s heart rate (HR) is around ___ beats/min.
An infant’s heart rate (HR) is about 120 beats/min, and fetal heart rates (HR) are about 140 beats/min.
(Herlihy, 2020, p. 329)
70, 80
100
(Herlihy, 2020, p. 329)
Exercise (decreases/increases) heart rate (HR).
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increases
(Herlihy, 2020, p. 329)
Sympathetic nerve firing stimulates the sinoatrial (SA) node, causing (decreased/increased) heart rate (HR).
Stimulation of the parasympathetic (vagus) nerve (decreases/increases) heart rate (HR).
(Herlihy, 2020, p. 329)
increased
decreases
(Herlihy, 2020, p. 329)
Several hormones affect heart rate (HR).
For example, epinephrine and norepinephrine (adrenal gland hormones) and thyroid hormone (decrease/increase) heart rate (HR).
(Herlihy, 2020, p. 329)
increase
(Herlihy, 2020, p. 329)
Many disease states affect heart rate (HR).
For example, a sick ___ (___) ___ may fire too slowly, thereby slowing the heart too much.
(Herlihy, 2020, p. 329)
sinoatrial (SA) node
(Herlihy, 2020, p. 329)
Vagal discharge following a heart attack [myocardial infarction (MI)] (decreases/increases) heart rate (HR), predisposing the heart to lethal rhythm disorders.
(Herlihy, 2020, pp. 329, 330)
decreases
(Herlihy, 2020, pp. 329, 330)
A high fever, hyperthyroidism, and persistent sympathetic activity can (decrease/increase) heart rate (HR), overworking the heart and causing it to fail.
(Herlihy, 2020, p. 330)
increase
(Herlihy, 2020, p. 330)
Some drugs are administered for the purpose of changing the ___ (___).
Heavy coffee drinkers often experience palpitations (the heart feels “jumpy,” as if it has extra beats) because of the stimulatory effect of caffeine on the heart.
Because some drugs can profoundly alter the ___ (___), it must be monitored when these drugs are used.
(Herlihy, 2020, p. 330)
heart rate (HR) X 2
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Which factor is the blood amount pumped by the ventricle per beat?
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Stroke Volume
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An average resting stroke volume is ___ to ___ mL/beat (about 2 oz).
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60
80
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At rest, the ventricles pump out only about ___% of the blood in the ventricles.
Therefore, if the ventricles can be made to contract more forcefully, a greater percentage of the blood can be pumped per beat.
In other words, a greater contraction force can increase ___ ___.
As in the case of heart rate (HR), ___ ___ can change, thereby affecting cardiac output.
(Herlihy, 2020, p. 330)
67
stroke volume x 2
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(Herlihy, 2020, p. 329)
(Herlihy, 2020, p. 329)
Stroke volume can be altered through two ways: ___ heart law and an ___ effect.
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Starling’s
inotropic
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What heart law is the relationship of myocardial stretch to myocardial contractile force?
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Starling’s
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What heart law explains the greater the stretch of the myocardium, the stronger the force of contraction?
(Herlihy, 2020, p. 330)
Starling’s
(Herlihy, 2020, p. 330)
An increase in blood amount entering the ventricle, the venous return, causes the ventricle to ___.
___ increases the contraction force, which in turn increases stroke volume.
Conversely, a decrease in blood amount entering the ventricles causes less ___.
As a result, the contraction force decreases, thereby decreasing stroke volume.
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stretch
Stretch
stretch
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A second way to increase stroke volume is by strengthening the myocardial contraction force without stretching the myocardial fibers.
This is called a ___ ___ effect.
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positive inotropic
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Heart muscle stimulation by sympathetic nerves causes a ___ ___ effect.
Certain hormones and drugs, such as epinephrine, also cause this effect.
(Herlihy, 2020, p. 330)
positive inotropic
(Herlihy, 2020, p. 330)
Digoxin is the most famous of the ___ ___ drugs.
Some medications cause a ___ ___ effect, which is a decrease in contraction force, resulting in a weaker myocardial contraction.
(Herlihy, 2020, p. 330)
positive inotropic
negative inotropic
(Herlihy, 2020, p. 330)
Which effect is most often associated with the failing heart or with an undesirable drug side effect?
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Negative Inotropic
(Herlihy, 2020, p. 330)
Starling’s Heart Law
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(Herlihy, 2020, p. 330)
What is determined by, and therefore altered by, changes in heart rate (HR) and stroke volume?
(Herlihy, 2020, p. 331)
Cardiac Output
(Herlihy, 2020, p. 331)
The healthy heart can increase cardiac output ___ to ___ times the resting cardiac output.
(Herlihy, 2020, p. 331)
four
five
(Herlihy, 2020, p. 331)
What is the capacity to increase cardiac output above the resting cardiac output?
(Herlihy, 2020, p. 331)
Cardiac Reserve
(Herlihy, 2020, p. 331)
A person with a diseased heart may have little ___ ___ and therefore becomes easily fatigued with mild exercise.
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cardiac reserve
(Herlihy, 2020, p. 331)
What refers to the ventricle blood amount at the end of its resting phase (diastole)?
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End-Diastolic Volume (EDV)
(Herlihy, 2020, p. 332)
What determines ventricle stretch and is the basis of Starling’s heart law?
(Herlihy, 2020, p. 332)
End-Diastolic Volume (EDV)
(Herlihy, 2020, p. 332)
What is the ventricle blood amount at the end of diastole; it is the same as the end-diastolic volume (EDV)?
(Herlihy, 2020, p. 332)
Preload
(Herlihy, 2020, p. 332)
An increased ___ stretches the ventricles, causing a stronger contraction force.
The stronger contraction increases stroke volume and cardiac output.
(Herlihy, 2020, p. 332)
preload
(Herlihy, 2020, p. 332)
Drugs can also affect ___.
For example, a drug may dilate the veins, causing blood to pool in the veins, thereby decreasing venous return, ___, stroke volume, and cardiac output.
Another drug may constrict the veins; this increases blood flow to the ventricles, thereby increasing venous return, ___, stroke volume, and cardiac output.
(Herlihy, 2020, p. 332)
preload x 3
(Herlihy, 2020, p. 332)
When the ventricle contracts, it pumps about ___% of its volume [end-diastolic volume (EDV)]; therefore some blood remains in the ventricle.
The percentage of the end-diastolic volume (EDV) that is pumped is called the ___ ___.
(Herlihy, 2020, p. 332)
67
ejection fraction
(Herlihy, 2020, p. 332)
What is an indication of cardiac health?
(Herlihy, 2020, p. 332)
Ejection Fraction
(Herlihy, 2020, p. 332)
A healthy heart can increase its ___ ___ to 90% with exercise.
A weakened, failing heart is characterized by a decrease in ___ ___, perhaps to as low as 30%.
(Herlihy, 2020, p. 332)
ejection fraction x 2
(Herlihy, 2020, p. 332)
What refers to resistance or opposition to blood flow?
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Afterload
(Herlihy, 2020, p. 332)
The pinched aorta can represent a number of clinical conditions such as aortic valve stenosis and systemic hypertension.
If the person develops high blood pressure, ___ increases and the ventricle must work harder to pump blood into the aorta.
As in the case of any other muscle that overworks, the left ventricular myocardium enlarges or ___.
The enlarged left ventricle will eventually fail as a pump.
(Herlihy, 2020, p. 332)
afterload
hypertrophies
(Herlihy, 2020, p. 332)
Right ventricle ___ is determined by the pressure within the pulmonary trunk and pulmonary arteries.
If pulmonary artery pressure rises (increased ___), the right ventricle must work harder to pump blood and therefore ___.
(Herlihy, 2020, p. 332)
afterload x 2
hypertrophies
(Herlihy, 2020, p. 332)
Right ventricular ___ frequently occurs in response to chronic lung diseases such as emphysema and asthma.
The elevation in pulmonary artery pressure and right ventricular hypertrophy is called ___ ___.
___ ___ often causes the right ventricle to fail as a pump.
(Herlihy, 2020, p. 332)
hypertrophy
cor pulmonale
(Herlihy, 2020, p. 332)
A drug that relaxes and dilates peripheral circulation blood vessels can lower blood pressure and therefore decrease the ___.
The reduction in ___ reduces the heart’s work.
Conversely, a drug that constricts periphery blood vessels increases, ___ thereby increasing heart workload.
(Herlihy, 2020, p. 332)
afterload x 3
(Herlihy, 2020, p. 332)
(Herlihy, 2020, p. 333)
(Herlihy, 2020, p. 333)
