Chapter 10 Posttest Flashcards
- The middle layer of the heart wall that contains the atrial and ventricular muscle fibers necessary for contraction is the:
A. Epicardium
B. Pericardium
C. Myocardium
D. Endocardium
C
The thick, muscular middle layer of the heart wall that contains the atrial and ventricular muscle fibers necessary for contraction in the myocardium
- The _______ supplies the right atrium and right ventricle with blood
A. Circumflex (Cx) artery
B. Right coronary artery (RCA)
C. Left main coronary artery
D. Left anterior descending (LAD) artery
B
A branch of the right coronary artery supplies the right atrium and right ventricle with blood
- The contribution of blood that is added to the ventricles and results from atrial contraction is called
A. Afterload
B. Atrial kick
C. Cardiac output
D. Peripheral resistance
B
The flow of blood from the superior and inferior vena cava into the atria is normally continuous. About 70% of this blood flows directly through the atria and into the ventricles before the atria contract; this is called passive filling. When the atria contract add additional 10% to 30% of the returning blood is added to filling of the ventricles. This additional contribution of blood resulting from atrial contraction is called atrial kick. Afterload is the pressure or resistance against which the ventricles must pump to reject blood. Cardiac output is the amount of blood pumped into the aorta each minute by the heart; it is defined as the stroke multiplied by the heart rate. Peripheral resistance is the resistance to the flow of blood, determined by blood vessel, diameter, and tone of the vascular musculature.
- The right atrium receives deoxygenated blood from which of the following vessels?
A. Aorta
B. Coronary sinus
C. Inferior vena cava
D. Superior vena cava
B, C, D
The right atrium receives deoxygenated blood from the superior vena cava (which carries blood from the head and upper extremities), the inferior vena cava (which carries blood from the lower body), and the coronary sinus (which receives blood from the intracranial circulation).
- Which of the following are semilunar valves?
A. Aortic
B. Mitral
C. Pulmonic
D. Tricuspid
A, C
Pulmonic and aortic valves are semi lunar valves. Semi lunar valves prevent backflow of blood from the aorta and pulmonary arteries into the ventricles. The tricuspid and mitral valves are AV valves, separate the atria from the ventricles
- Stimulation of parasympathetic nerve fibers typically results in which of the following actions?
A, constriction of coronary blood vessels
B. Increased strength of cardiac muscle contractions
C. Increased rate of discharge of Sinoatrial (SA) node
D. Slowed conduction through the atrioventricular (AV) node
D
Parasympathetic (inhibitory) nerve, fiber supply, the SA node, atrial muscle, and the AV bundle of the heart by the vagus nerves. Parasympathetic stimulation has the following actions:
Slows the rate of discharge of the SA node
Slows conduction through the AV node
Decreases the strength of atrial contraction
Can cause a small decrease in the force of ventricular contraction
- Which of the following are primary branches of the left main coronary artery?
A. Cx branch
B. LAD branch
C. Marginal branch
D. Posterior descending branch
A, B
Left main coronary artery supplies, oxygenated blood to its two primary branches; the LAD, which is also called the anterior intraventricular artery, and the circumflex artery
- ________ cells are specialized cells of the electrical conduction system responsible for the spontaneous generation and conduction of electricle impulses,
A. Working
B. Contractile
C. Pacemaker
D. Mechanical
C
Cardiac cells have either a mechanical (contractile) or an electrical (pacemaker) function. Pacemaker cells are specialized cells of the electrical conduction system. Pacemaker cells also may be referred to as conducting cells or automatic cells. They are responsible for the spontaneous generation and conduction of electrical impulses.
- The absolute refractory period:
A. Begins with the onset of the P wave and terminates with the end of the QRS complex
B. Begins with the onset of the QRS complex and terminates at approximately the apex of the T wave
C. Begins with the onset of the QRS complex and terminates with the end of the T wave
D. Begins with the onset of the P wave and terminates with the beginning of the QRS complex
B
During the absolute refractory period, the cell with no response to further stimulation within itself. This means the mild cardio working cells contract, and the cells of the electrical conduction system cannot conduct an electrical impulse, no matter how strong the internal electrical stimulus. On the ECG, the absolute refractory period begins with the onset of the QRS complex and terminates at approximately the apex of the T wave.
- ST segment is measured form the:
A,. End of the QRS to the end of the T wave
B. Beginning of the QRS complex to end of the T wave
C. End of the QRS complex to beginning of the T wave
D. Beginning of the QRS complex to the beginning of the T wave
C
The portion of the ECG tracing between the QRS complex and the T wave in the ST segment. The term ST segment is used, regardless of whether the final wave of the QRS complex is an R or an S wave the segment represents the early part of repolarization of the right and left ventricles. The normal ST segment begins at the isoelectric line, extends from the end of the S wave, and curves gradually upward to the beginning of the T wave
- Which of the following states is true regarding the QT interval?
A. The QT interval represents atrial depolarization, followed immediately by atrial systole
B. The QT interval corresponds to atrial depolarization and impulse delay in the AV node
C. The QT interval represents the ventricular systole.
D. The QT interval represents the time from the initial depolarization of the ventricles to the end of the ventricular repolarization
D
The QT interval, measured from the beginning of the QRS complex to the end of the T wave, represents the time from initial polarization of the ventricles to the end of ventricular re-polarization
- Where is the positive electrode placed in lead III?
A. Left arm
B. Right arm
C. Left leg/foot
D. Right leg/foot
C
Lead III records the difference in electrical potential between the left leg (+) and the left arm (-) electrodes. In the lead III, deposit electrode is placed on the left leg, and the negative electrode is placed on the left arm
- A junctional escape rhythm occurs because of
A. Severe chronic obstructive pulmonary disease
B. Multiple irritable sites firing within the AV junction.
C. Slowing of the rate of the heart primary peacemaker.
D. Intrathoracic pressure changes associated with the respiratory cycle
C
Junctional escape beats and rhythms occur when the SA node fails to paste the heart or AV conduction fails
- How do you determine whether the atrial rhythm on an electrocardiogram tracing is regular or irregular?
A. Compare QT intervals.
B. Compare PR intervals.
C. Compare P to P intervals
D. Compare R to R intervals
C
To evaluate the rhythmicity of the atrial rhythm, the interval between two consecutive P waves is measured and compared to succeeding P to P intervals
- Which of the following ECG leads used to distinct electrodes, one of which is positive and the other negative?
A. Lead I
B. Lead II
C. Lead V1
D. Lead V6
E. Lead aVF
A, B
A bipolar lead is an ECG lead that has a positive and negative electrode. Each lead records the difference in electrical potential (voltage) between two selected electrodes. Although ECG leads are technically bipolar, leads I, and III use two different electrodes, one of which is connected to the positive input of the ECG machine and the other to the negative input
- Leads II, III, and aVF view the hearts ______ surface?
A. Lateral
B. Anterior
C. Inferior
D. Inferobasal
C
Leads II, III, and aVF view the hearts inferior surface
- An ECG rhythm strip shows a ventricular rate of 46, a regular rhythm, a PR interval of 0.14 seconds, a QRS of 0.06 seconds, and one positive P wave before each QRS. This rhythm is.
A. Sinus arrest.
B. Sinus rhythm.
C. SA block.
D. Sinus bradycardia.
D
The rate of a sinus bradycardia is less than 60 bpm . R to R and P to P intervals are regular, P waves are positive in lead II, and one precedes each QRS complex. The PR interval is within normal limits and the QRS duration is 0.11 seconds or less unless is abnormally conducted
- In sinus arrhythmia, a gradual decreasing of the heart rate is usually associated with
A. Expiration.
B. Inspiration.
C. Excessive caffeine intake.
D. Early signs of heart failure.
A
In sinus arrhythmia , the heart rate increases gradually during inspiration (R to R intervals shorten) and decrease with expiration (R to R intervals lengthen).
- SA block is a disorder of impulse _______ and sinus arrest is a disorder of impulse _________
A. Formation, conduction
B. Conduction, formation
B
In SA block, which is also called sinus acid block, the peacemaker cells within the essay note initiate an impulse, but it is blocked as it exits the SA node; thus, SA block is a disorder of impulse conduction. Sinus arrest, which is also called sinus or SA arrest, is a disorder of impulse formation. In sinus arrest, the pacemaker cells of the SA node to initiate an electrical impulse for one or more beats resulting in absent PQRST complexes on the ECG
- Signs and symptoms experience during a tacky dysrhythmia are usually primarily related to
A. Atrial irritability.
B. Vasoconstriction
C. Slowed conduction through the AV node
D. Decrease ventricular filling time and stroke volume
D
The heart demand for oxygen increases as the heart rate increases. As the heart rate increases, there is less time for the ventricles to fill and less blood for the ventricles to pump out with each contraction, which can lead to decreased cardiac output. Because the coronary arteries fill when the ventricles are at rest, rapid heart rates decrease the time available for coronary artery filling. This decreases the blood supply. Chest discomfort can result the supplies of blood and oxygen to the heart are inadequate