17 Function of the Heart- Herlihy: The Human Body in Health and Illness, 7th Edition

Systole and diastole describe the function of the

myocardium

During atrial systole, the

ventricles are relaxed.

What happens during ventricular diastole?

The ventricles are filling with blood

Which of the following is the most likely consequence of a very rapid heart rate?

Decreased ventricular filling (with blood)

Which of the following does not happen to a ventricle?

Discharge of the vagal nerve

Which of the following is most likely to relieve an anxiety-induced tachycardia?

Beta1-adrenergic blocker

Which of the following is responsible for the Starling effect?

End-diastolic volume (EDV) or preload

Which of the following is most likely to increase stroke volume?

A (+) inotropic drug

Which of the following is most likely to increase ejection fraction?

Activation of beta1-adrenergic receptors

Which of the following is the same as end-diastolic volume?

Preload

What term refers to the amount of blood pumped by the ventricle in one beat?

Stroke volume

Which term refers to the amount of blood pumped by the heart in 1 minute?

Cardiac output

Sympathetic nerve stimulation of the myocardium

causes a (+) inotropic effect

Vagal stimulation to the heart causes

heart rate to slow.

Excess vagal stimulation to the SA node is most likely to cause

bradycardia.

Which of the following is descriptive of the vagus nerve?

Parasympathetic

Heart rate and stroke volume determine

cardiac output.

A drug (e.g., atropine) that blocks the effects of the vagus nerve

increases heart rate

Activation of the muscarinic receptors by acetylcholine

slows heart rate.

Decreased blood flow through the coronary arteries is most likely to cause

angina pectoris.

What is the term for the sequence of events that occur during one heartbeat?

Cardiac cycle

Which of the following is approximately 70 mL?

An average stroke volume

Which of the following refers to a positive inotropic effect?

An increased myocardial contractile force

inotropic effect

a change in the strength or force of myocardial contraction that does not involve stretching the myocardial fibers

What is the term that refers to an increase in stroke volume in response to the stretching of the heart?

Starling's law of the heart

Atropine is a muscarinic antagonist and is therefore used to

relieve bradycardia.

Which of the following is descriptive of a drug that causes a (+) inotropic effect, a (+) dromotropic effect, and a (+) chronotropic effect?

Sympathomimetic

Sympathomimetic

agent that mimics the effects of the sympathetic nervous system

Vagomimetic

any action or drug that resembles the action of the vagus nerve

Which of the following drugs is sympathomimetic?

Beta1-adrenergic agonist

Beta1-adrenergic agonist

increases cardiac output

An increased preload

increases stroke volume.

Increased afterload (e.g., hypertension)

. increases the work of the heart.

Cardiac output

is determined by heart rate and stroke volume

Increased return of the blood to the heart stretches the muscle, thereby

increasing stroke volume.

ejection fraction

measurement of the volume percentage of left ventricular contents ejected with each contraction

An ejection fraction of 30% is

characteristic of a failing heart.

A stenotic aortic valve

increases afterload, thereby increasing the work of the left ventricle.

stenotic

pertaining to a narrowing or stricture

Which of the following is the most likely consequence of acute left ventricular failure?

Pulmonary edema

Most of the symptoms of acute left-sided heart failure are

respiratory in nature (e.g., dyspnea, orthopnea).

Which of the following is an example of forward failure?

Diminished renal blood flow stimulates the kidney to decrease urinary output and retain Na+ and water.

Digoxin, a drug used in the treatment of heart failure, increases contractile force and is therefore called a

(+) inotropic agent.

dromotropic agent

affects the conduction speed in the AV node, and subsequently the rate of electrical impulses in the heart.

chronotropic agent.

Increases (positive) or decreases (negative) heart rate (Atropine, Dopamine, Epinephrine)

Atropine

muscarinic antagonist

An increase in venous return causes an increase in cardiac output. This is accomplished by

Starling's law of the heart

Milliliters/beat beats/min defines

cardiac output

The amount of blood in the ventricle at the end of its resting phase is the

a. end-diastolic volume (EDV). b. amount of blood in the ventricle at the end of its resting phase. c. preload. d. All of the above are true. ANS: D

Under what condition is end-diastolic volume (EDV) most likely to increase while ejection fraction decreases?

Heart failure

end-diastolic volume (EDV)

volume of blood in each ventricle at end of ventricular diastole

A change in preload causes a change in myocardial contractile force. This response is known as

Starling's law of the heart.

A drug causes a (+) inotropic effect, a (-) dromotropic effect, and a (-) chronotropic effect. What drug response would you expect to observe?

Slow heart rate

A patient in heart failure is given a drug that is classified as a beta1-adrenergic agonist. The drug

activates the beta1-adrenergic receptors and causes a (+) inotropic effect.

Which of the following statements is correct about cardiac output?

Cardiac output is determined by heart rate and stroke volume.

Increased return of blood to the heart stretches the heart muscle, thereby

increasing stroke volume.

Milliliters per minute describes

cardiac output

Atropine, a muscarinic blocker,

increases heart rate.

Starling's law of the heart relates force of myocardial contraction with a. heart rate.

preload

Venodilation

decreases preload.

An elevation in pulmonary artery pressure is most likely to cause

right ventricular hypertrophy.

Which of the following is least likely to be used in the treatment of left ventricular failure and pulmonary edema?

Peripheral vasoconstrictor such as norepinephrine (Levophed)

Jugular vein distention is most associated with

right-sided heart failure.

Atropine is anticholinergic and antimuscarinic and therefore

is used to treat bradydysrhythmias such as heart block and a prolonged P-R interval.

With which of the following is inotropism most associated?

Force of myocardial contraction

inotropism

force of contraction

A very anxious person appears in the ER. He has a heart rate of 160 beats/min and indicates that he has a history of panic attacks. He is prescribed an antianxiety agent and a drug to slow his heart rate. Identify the drug (to slow heart rate).

Beta1-adrenergic blocker

Which of the following is most apt to cause a (+) inotropic effect?

Use of a beta1-adrenergic agonist

Which of the following elicits the same effect as vagomimetic activity?

Use of a muscarinic agonist

Which of the following describes Starling's law of the heart?

a. An increase in venous return to the ventricles causes an increase in cardiac output. b. An increase in preload increases cardiac output. c. A decrease in preload decreases cardiac output. d. All of the above are true.

With which term is afterload most associated?

Resistance

With which term is preload synonymous?

End-diastolic volume

Digoxin exerts a (-) chronotropic effect and (+) inotropic effect. Which of the following describes these effects?

Decreases heart rate and strengthens myocardial contraction

Cor pulmonale refers to

elevation in pulmonary artery pressure and right ventricular hypertrophy.