NCSBN NCLEX QUESTIONS

Week 4 NCLEX Practice Questions ScienceMedicineCardiology MngrDwight_K_Schrute Save Week 5 NCLEX Practice Questions

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NCSBN NCLEX QUESTIONS

408 terms ANNEMARIEBISHOP Preview Week 4 54 terms Ash When a papillary muscle in the left ventricle ruptures, the mitral valve leaflets do not close completely, resulting in which condition?

• acute myocardial infarction.
• aortic valve failure.
• cardiac murmur.
• systemic venous congestion.

Cardiac murmur A dysfunction of the chordae tendineae or of a papillary muscle can cause incomplete closure of an atrioventricular valve, which results in backflow of blood into the atrium and produces a murmur. If a papillary muscle in the left ventricle ruptures, the mitral valve leaflets do not close completely. Clinically, this causes acute mitral regurgitation and an audible murmur that can be auscultated with a stethoscope.Aortic valve dysfunction pathologically alters which structure of the heart?

• left atrium.
• left ventricle.
• right ventricle.
• mitral valve.

Left ventricle Aortic valve dysfunction from any cause not only affects the valve leaflets but also pathologically alters the shape of the left ventricle.

A physiologic cardiac shunt occurs when there is mixing of deoxygenated blood (usually venous blood with reduced oxygen content) with arterial oxygenated blood. In the heart, this is demonstrated by which mechanism?

• atrial septal defect.
• patent foramen ovale.
• thebesian veins.
• ventricular septal defect.

Thebesian veins The thebesian veins are small vessels that connect capillary beds directly with the cardiac chambers via irregular endothelium-lined sinuses within the myocardium. The thebesian veins add a small quantity of deoxygenated blood to the oxygenated blood in the left ventricle.The time from the beginning of the cardiac action potential (AP) until the time when the fiber can accept another AP is known as which period?

• excitability
• depolarization
• relative refractory
• absolute refractory

Absolute refractory The time from the beginning of the AP until the fiber can accept another AP is called the effective or absolute refractory period. During this period, the cell cannot be depolarized regardless of the amount or intensity of the stimulus.The nurse auscultates a murmur at the fifth intercostal space at the midclavicular line on the left side. The nurse realizes that this is caused by which incompetent heart valve?

• Aortic
• Pulmonic
• Mitral
• Tricuspid

Mitral This is the correct location of the mitral valve. The aortic valve is located at the second right intercostal space at the right sternal border. The pulmonic valve is located at the second left intercostal space at the left sternal border. The tricuspid valve is located at the fourth left intercostal space at the left sternal border.Pulse pressure is the difference between systolic pressure and diastolic pressure. What will happen to the patient's pulse pressure if the patient becomes volume depleted?

• narrow
• widen
• remain unchanged
• increase

Narrow A symptom of vasoconstriction is a narrowed pulse pressure. A widened pulse pressure is associated with vasodilation.

Cardiac output is the amount of blood ejected from the heart in 1 minute. If the patient's heart rate (HR) is 72 beats/min and stroke volume (SV) is

70 mL/beat, cardiac output is:

• 2 L/min
• 5.04 L/min
• 142 L/min
• 120 L/min

5.04 L/min Cardiac output is HR × SV = 70 × 72 beats/min × 70 mL/beats = 5040 mL/min = 5.04 L/min.

In an effort to improve cardiac output, a positive inotropic drug is given to:

• increase the contractility of the heart.
• increase the heart rate.
• increase the conduction velocity.
• increase the automaticity of the heart.

Increase the contractility of the heart Positive inotropic drugs increase the force of contraction of the heart to improve cardiac output. A drug that increases heart rate would be a positive chronotrope. A drug that increases conduction velocity would speed conduction from the SA to the AV node, and a drug that increases automaticity would stimulate electrical impulses.The nurse is explaining the function of the atrioventricular (AV) node to the student nurse. Which statement is true? (Select all that apply.)

• The conduction time of impulses from the sinoatrial (SA) to the AV node allows the ventricles to fill with blood during diastole.
• The AV node prevents rapid heart rates from destabilizing the heart.
• The AV node provides a backup pacemaker if the SA node fails.
• The AV node sends impulses forward only.
• The AV is located on the left side of the interatrial septum

The conduction time of impulses from the sinoatrial (SA) to the AV node allows the ventricles to fill with blood during diastole.The AV node prevents rapid heart rates from destabilizing the heart.The AV node provides a backup pacemaker if the SA node fails.Rationale The conduction time of impulses from the SA to the AV node allows the ventricles to fill with blood during diastole, the AV node prevents rapid heart rates from destabilizing the heart, and the AV node provides a backup pacemaker if the SA node fail are all true statements about the function of the AV node. The AV node conducts impulses forward and backward (retrograde) and is located on the right side of the interatrial septum.

What part of the arterial system contains the greatest amount of elastin?

• Aorta
• Pulmonary artery
• Common carotids
• Arterioles

Aorta The aorta contains the greatest amount of elastic tissue. This is necessary because of the sudden shifts in pressure created by the left ventricle.Which structure of the microcirculation allows for solute diffusion across the endothelium?

• arteriole.
• venule.
• capillary.
• precapillary sphincter.

Capillary The capillary consists of a single cell layer of endothelium and is devoid of muscle and elastin. This arrangement allows solutes to diffuse in and out of the capillaries unimpeded by mechanical barriers. Capillaries normally retain large structures, such as red blood cells, but are highly permeable to smaller solutes, such as electrolytes.Which intracellular structure, essential for cardiac contraction, stores calcium ions for release and use after depolarization?

• sarcoplasmic reticulum.
• sarcomere.
• sarcolemma.
• transverse tubules.

Sarcoplasmic reticulum An extremely important intracellular structure that is necessary for successful contraction is the sarcoplasmic reticulum. Calcium ions are stored in the sarcoplasmic reticulum and released for use after depolarization.In regard to cardiac action potential, which statement best describes phase 3?It consists of partial repolarization, as the action potential returns toward zero, when the rapid influx of NA+ is terminated It consists of rapid depolarization, opening of the fast Na+ channels and causing a rapid influx of Na+ ions.It consists of repolarization, preventing further influx of Ca2+/Na+ while promoting efflux of K+ out of the cell It consists of resting membrane potential; excess Na+ that entered the cell is removed from the cell in exchange for K+ by means of the Na+/K+ pump.It consists of repolarization, preventing further influx of Ca2+/Na+ while promoting efflux of K+ out of the cell The repolarization phase is described as phase 3, and it depends on two processes. The first is the inactivation of the slow channels, which prevents further influx of Ca2+ and Na+. The other is the continued efflux of K+ out of the cell.