Chapter 20 Wiley Plus – Flashcards
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The visceral layer of the serous pericardium
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Is the outer layer of the heart
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The atria receive blood from all of the following
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1. Pulmonary veins
2. Superior vena cava
3. Coronary sinus
4. Inferior vena cava
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The thickest wall in the heart due to its increased work load is the
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Left ventricle
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Which of the following is the correct pathway of blood starting at the right atrium?
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Right atrium, right ventricle, pulmonary trunk, pulmonary veins, left atrium, left ventricle, aorta
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When comparing cardiac muscle tissue to skeletal muscle tissue, which statement is true?
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Both types of fibers are striated
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A skeletal muscle may undergo tetanus but cardiac muscle cannot
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True
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What is occurring during isovolumetric contraction?
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All four valves are closed
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The amount of blood ejected from either ventricle every minute is called
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Cardiac output
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True statments
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1. The walls of the ventricles are thicker because the ventricles pump blood under high pressure over greater distances
2. The wall of the right ventricle is thinner than that of the left ventricle because the right side of the heart pumps blood a shorter distance at lower pressure
3. Although the right side of the heart has a smaller workload, the right and left ventricle stimultaneously eject the same amount of blood
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Prolapse of the atrioventricular valves is prevented by
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Contraction of the papillary muscles
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The semilunar valves open when pressure in the right and left ventricles exceeds that in the pulmonary trunk and aorta, respectively
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True
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The intercalated discs seen in the cardiac myocytes
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1. Have desmosomes which help to hold the muscle fibers together
2. Have gap junctions which allow action potentials to conduct from one muscle fiber to the next
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Which represents the correct flow of excitation through the cardiac conduction system?
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SA node, AV node, bundle of His, right and left bundle branches, Purkinje fibers
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What occurs after the QRS phase of the ECG
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The ventricles contract
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Which of the following places the phases of the cardiac cycle in correct order?
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Atrial contraction, isovolumetric contraction, ventricular ejection, isovolumetric relaxation, ventricular filling, atrial contraction
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Parasympathetic nervous system stimulation of the heart has little effect on force of contraction because the vagus nerve does not supply most of the ventricular myocytes
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True
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If the heart rate is 65 beats/min and the stroke volume in 70 ml, cardiac output is 135 ml/min
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False
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The membrane that surrounds and protects the heart is called the
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Pericardium
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The outermost layer of the pericardium, which consists of inelastic dense irregular connective tissue, is called the
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Fibrous pericardium
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Which of the following is used to reduce friction between the layers of membranes surrounding the heart?
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Pericardial fluid
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Which layer of the heart wall consists of cardiac muscle tissue?
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Myocardium
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Identify the pouch-like structure that increases the total capacity of the atrium
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Auricle
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Blood leaving the left ventricle passes through which of the following structures?
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Aortic semilunar valve
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Which valve below prevents blood from flowing back into the right ventricle?
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Pulmonary semilunar valve
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What of the following chambers of the heart contain deoxygenated blood?
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Right atrium and right ventricle
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Which network of specialized cardiac muscle fibers provide a path for each cycle of cardiac excitation to progress through the heart?
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Cardiac conduction system
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Which of the following correctly lists the sequence of structures that a cardiac action potential follows in order to excite normal contraction of the heart?
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SA node, AV node, Bundle of His, Purkinje fibers
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In comparison to skeletal muscle fibers, the contractile fibers of the heart are depolarized for _ period of time
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A longer
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Which term refers to the period of time during a cardiac cycle when contraction of a chamber occurs and pressure within the chamber rises?
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Systole
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During which of the following periods does the largest volume of blood enter the arteries?
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Ventricular systole
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Stimulation of which nerve reduces heart rate?
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Vagus nerve
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Which wave in an electrocardiogram represents repolarization of the ventricles?
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T wave
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Which of the following selections lists conditions that would lead to increased stroke volume?
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Increased preload, decreased afterload, increased contractility
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Isovolumetric contraction is the phase of the cardiac cycle in which
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Ventricular pressure increases and ventricular volume remains the same
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Semilunar valves function to prevent blood from flowing back into the
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Ventricles during ventricular diastole
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Atrial systole is necessary to
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Fill the ventricles with blood
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When all heart valves are closed during isovolumetric ventricular contraction, the amount of blood (volume) is constant but blood pressure increases
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True
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Towards the end of ventricular systole when ventricular blood pressure exceeds aortic blood pressure
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Semilunar valves open
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Semilunar valves close during ventricular diastole to prevent blood from flowing from aortas into the ventricles
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True
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Ventricular muscle is relaxed
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1. During ventricular diastole
2. Approximately half of the cardiac cycle
3. During atrial systole
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The right side of the heart is concerned with
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Pulmonary circulation
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The first sound heard in a stethoscope during the cardiac cycle is the
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Closing of the AV valves
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Blood leaves the heart during
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Ventricular ejection
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Cardiac output can be determined by multiplying the heart rate by the stroke volume.
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True
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The typical cardiac output for a healthy adult is around 5-liters per minute
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True
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Extreme exercise can increase the cardiac output up to 100-fold
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False
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A normal resting stroke volume is around 70-mL.
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True
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Contraction of the cardiac muscle sarcomeres during ventricular systole provides the force needed to eject blood from the heart
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True
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Hypertension
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Increases aortic pressure
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The P-wave in an electrocardiogram occurs during
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Atrial depolarization
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Atrial repolarization occurs during ventricular depolarization and, consequently, would be viewed on an electrocardiogram (if it was visible) during
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The QRS complex
