Advanced Pathophysiology Exam 4: Questions and Answers, Exams of Nursing, Exams of Nursing

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Nurs601 ADVANCED

PATHOPHYSIOLOGY Quiz 4

1. Which statement made by a student indicates the healthcare professional needs to describe the pericardium again? a. The pericardium is a double-walled membranous sac that encloses the heart. b. It is made up of connective tissue and a surface layer of squamous cells. c. The pericardium protects the heart against infection and inflammation from the lungs and pleural space. d. It contains pain and mechanoreceptors that can elicit reflex changes in blood pressure and heart rate. - ANS: B The pericardium is made up of a surface layer of mesothelium over a thin layer of connective tissue. The healthcare professional would need to re-explain if the student stated the pericardium is made up of connective tissue and a layer of squamous cells. The other statements are accurate.
2. Which cardiac chambers have the thinnest wall and why? a. The right and left atria; they are low-pressure chambers that serve as storage units and conduits for blood. b. The right and left atria; they are not directly involved in the preload, contractility, or afterload of the heart. c. The left ventricle; the mean pressure of blood coming into this ventricle is from the lung, which has a low pressure. d. The right ventricle; it pumps blood into the pulmonary capillaries, which have a lower pressure compared with the systemic circulation. - ANS: A The two atria have the thinnest walls because they are low-pressure chambers that serve as storage units and conduits for blood that is emptied into the ventricles. The ventricles have thicker walls in order to pump blood against resistance.
3. Which chamber of the heart endures the highest pressures? a. Right atrium b. Left atrium c. Left ventricle d. Right ventricle - ANS: C Pressure is greatest in the left ventricle with a systolic range of 90 to 140 mmHg. The right ventricle is next with a systolic range of 15 to 28 mmHg, followed by the left and right atria, respectively.
4. What is the process that ensures mitral and tricuspid valve closure after the ventricles are filled with blood? a. Chordae tendineae relax, which allows the valves to close. b. Increased pressure in the ventricles pushes the valves to close. c. Trabeculae carneae contract, which pulls the valves closed. d. Reduced pressure in the atria creates a negative pressure that pulls the valves closed. - ANS: B During ventricular relaxation, the two atrioventricular valves open and blood flows from the higher pressure atria to the relaxed ventricles. With increasing ventricular pressure, these valves close and prevent backflow into the atria as the ventricles

contract. The chordae tendineae attach the bottom end of the AV valves to the papillary muscles. The endocardium covers beamlike projections of muscle tissue, called trabeculae carneae. The valves are not pulled closed by reduced atrial pressure.

1. A student asks the healthcare professional to explain the function of the papillary muscles. What response by the professional is best? a. The papillary muscles close the semilunar valves. b. These muscles prevent backward expulsion of the atrioventricular valves. c. They open the atrioventricular valves. d. The papillary muscles open the semilunar valves. - ANS: B The papillary muscles are extensions of the myocardium that pull the cusps of the AV valves together and downward at the onset of ventricular contraction, thus preventing their backward expulsion into the atria. They do not close the semilunar valves or open the AV valves or semilunar valves.
2. During the cardiac cycle, why do the aortic and pulmonic valves close after the ventricles relax? a. Papillary muscles relax, which allows the valves to close. b. Chordae tendineae contract, which pulls the valves closed. c. Reduced pressure in the ventricles creates a negative pressure, which pulls the valves closed. d. Blood fills the cusps of the valves and causes the edges to merge, closing the valves. - ANS: D When the ventricles relax, blood fills the cusps and causes their free edges to meet in the middle of the vessel, closing the valve and preventing any backflow. The papillary muscles function in the tricuspid and mitral valves as do the chordae tendineae. Reduced pressure does not pull the valves closed.
3. Oxygenated blood flows through which vessel? a. Superior vena cava b. Pulmonary veins c. Pulmonary artery d. Coronary veins - ANS: B The four pulmonary veins, two from the right lung and two from the left lung, carry oxygenated blood from the lungs to the left side of the heart. All other veins carry deoxygenated blood. The superior vena cava returns deoxygenated blood from systemic circulation to the right atrium. The pulmonary arteries carry deoxygenated blood from the right side of the heart into the lungs.
4. A healthcare professional tells a student that a patient has lost atrial kick. What would the student expect to see when examining this patient? a. Improvement in atrial dysrhythmias b. Increased blood pressure c. Signs of decreased cardiac output d. Elevations in serum troponin levels - ANS: C Left atrial contraction, the atrial kick, provides a significant increase of blood to the left ventricle. This would help to increase cardiac output. With the loss of this atrial kick, the student would expect to find signs of decreased cardiac output such as decreased blood pressure or tachycardia. Loss of atrial kick would not improve

Phase 0 consists of depolarization and represents rapid sodium entry into the cell. A deficit of sodium could be a possible contributor. The other electrolyte disturbances would not be directly correlated to this problem.

1. A healthcare professional is caring for a patient who has a delay in electrical activity reaching the ventricle as seen on ECG. What ECG finding would the healthcare professional associate with this problem? a. A prolonged ST interval b. Variability in measurement with heart rate c. PR interval measuring 0.28 sec d. A QRS complex measuring 0.08 sec - ANS: C The PR interval is a measure of time from the onset of atrial activation to the onset of ventricular activation; it normally ranges from 0.12 to 0.20 sec. The PR interval represents the time necessary to travel from the sinus node through the atrium, the atrioventricular (AV) node, and the His-Purkinje system to activate ventricular myocardial cells. The measured PR of 0.28 sec is too long, signifying a delay in the conduction process from atrium to ventricle. The ST interval represents the time needed for ventricular depolarization. The QT interval is normally around 0.4 sec, but varies inversely with heart rate. The QRS measurement is within the normal range of less than or equal to 0.12 sec.
2. The cardiac electrical impulse normally begins spontaneously in the sinoatrial (SA) node because of what reason? a. It has a superior location in the right atrium. b. It is the only area of the heart capable of spontaneous depolarization. c. It has rich sympathetic innervation via the vagus nerve. d. It depolarizes more rapidly than other automatic cells of the heart. - ANS: D The electrical impulse normally begins in the SA node because its cells depolarize more rapidly than other automatic cells at a rate of 60 to 100 beats/min. The SA node's location does not influence this activity. Other areas of the heart include the AV node and the Purkinje fibers. The vagus nerve causes the heart rate to slow as part of the parasympathetic nervous system.
3. What period follows depolarization of the myocardium and represents a period during which no new cardiac potential can be propagated? a. Refractory b. Hyperpolarization c. Threshold d. Sinoatrial (SA) - ANS: A During the absolute refractory period, no new cardiac action potential can be initiated by a stimulus. The other options do not reflect the time period in which no stimulation will produce a new cardiac potential.
4. A patient has a disorder affecting ventricular depolarization. What ECG finding would the healthcare professional associate with this condition? a. Shortened PR interval b. Prolonged QRS interval c. QT interval variability d. Absence of P waves - ANS: B The QRS complex represents the sum of all ventricular muscle cell depolarizations. If a patient had ECG findings suggestive of problems with this activity, there would

be prolongation of the QRS interval. The PR interval reflects the amount of time needed for the action potential to travel from the atrium to the ventricle. QT interval variability is normal. An absence of P waves would indicate a problem with the SA node.

1. What can shorten the conduction time of action potential through the atrioventricular (AV) node? a. Parasympathetic nervous system b. Catecholamines c. Vagal stimulation d. Sinoatrial node (SA) - ANS: B Catecholamines speed the heart rate, shorten the conduction time through the AV node, and increase the rhythmicity of the AV pacemaker fibers. The vagal nerve is part of the sympathetic nervous system and stimulation will decrease heart rate. The SA node is responsible for generating the electrical activity of the heart, but is not responsible for the time it takes for it to travel through the AV node.
2. A patient had a myocardial infarction that damaged the SA node, which is no longer functioning as the pacemaker of the heart. What heart rate would the healthcare provider expect the patient to have? a. 60 to 70 beats/min b. 40 to 60 beats/min c. 30 to 40 beats/min d. 10 to 20 beats/min - ANS: B If the SA node is damaged, then the AV node will become the heart's pacemaker at a rate of approximately 40 to 60 spontaneous depolarizations per minute. The SA node normally fires at a rate of 60 to 100 beats/min. The Purkinje fibers can function as the heart's pacemaker and will fire at a rate of around 40 beats/min.
3. What is the effect of epinephrine on β3 receptors on the heart? a. Decreases coronary blood flow b. Supplements the effects of both β1 and β2 receptors c. Increases the strength of myocardial contraction d. Prevents overstimulation of the heart by the sympathetic nervous system - ANS: D β3 receptors are found in the myocardium and coronary vessels. In the heart, stimulation of these receptors opposes the effects of β1- and β2-receptor stimulation and negative inotropic effect. Thus β3 receptors may provide a safety mechanism that decreases myocardial contractility to prevent overstimulation of the heart by the sympathetic nervous system.
4. Where in the heart are the receptors for neurotransmitters located? a. Semilunar and atrioventricular (AV) valves b. Endocardium and sinoatrial (SA) node c. Myocardium and coronary vessels d. Epicardium and AV node - ANS: C Sympathetic neural stimulation of the myocardium and coronary vessels depends on the presence of adrenergic receptors, which specifically bind with neurotransmitters of the sympathetic nervous system. The β1 receptors are found mostly in the heart, specifically the conduction system (AV and SA nodes, Purkinje fibers) and the atrial and ventricular myocardium, whereas the β2 receptors are found in the heart and also on vascular smooth muscle. β3 receptors are also found in the myocardium and

1. A healthcare professional is caring for a patient who has continuous increases in left ventricular filing pressures. What disorder would the professional assess the patient for? a. Mitral regurgitation b. Mitral stenosis c. Pulmonary edema d. Jugular vein distention - ANS: C Pressure changes are important because increased left ventricular filling pressures back up into the pulmonary circulation, where they force plasma out through vessel walls, causing fluid to accumulate in lung tissues (pulmonary edema). Problems such as mitral regurgitation and mitral stenosis are valve problems, not directly related to this patient's situation. Jugular vein distention can be a sign of fluid overload.
2. The resting heart rate in a healthy person is primarily under the control of which nervous system? a. Sympathetic b. Parasympathetic c. Somatic d. Spinal - ANS: B The resting heart rate in healthy individuals is primarily under the control of parasympathetic stimulation.
3. The Bainbridge reflex is thought to be initiated by sensory neurons in which cardiac location? a. Atria b. Aorta c. Sinoatrial (SA) node d. Ventricles - ANS: A The Bainbridge reflex causes changes in the heart rate after intravenous infusions of blood or other fluid. The changes in heart rate are thought to be caused by a reflex mediated by volume receptors found only in the atria that are innervated by the vagus nerve.
4. A healthcare professional cares for older adults in a skilled nursing facility. What should the professional assess for in these individuals related to cardiovascular functioning? a. Increased rate of falling and dizzy spells b. Improved exercise tolerance c. A gradual slowing of the heart rate d. Progressive ECG changes - ANS: A The baroreceptor reflex is important in blood pressure control. Baroreceptor activity can decrease with age, slowing response to changes in blood pressure and posture. An older adult may not adjust rapidly to position changes, leading to falls and dizzy spells.
5. Reflex control of total cardiac output and total peripheral resistance is controlled by what mechanism? a. Parasympathetic stimulation of the heart, arterioles, and veins b. Sympathetic stimulation of the heart, arterioles, and veins c. Autonomic control of the heart only d. Somatic control of the heart, arterioles, and veins - ANS: B

Reflex control of total cardiac output and peripheral resistance includes (1) sympathetic stimulation of the heart, arterioles, and veins; and (2) parasympathetic stimulation of the heart only. Neither autonomic nor somatic controls are involved in this process.

1. What is the most important negative inotropic agent? a. Norepinephrine b. Epinephrine c. Acetylcholine d. Dopamine - ANS: C Chemicals affecting contractility are called inotropic agents. The most important negative inotropic agent is acetylcholine released from the vagus nerve. The most important positive inotropic agents produced by the body are norepinephrine released from the sympathetic nerves that supply the heart and epinephrine released by the adrenal cortex. Other positive inotropes include thyroid hormone and dopamine.
2. The right lymphatic duct drains into which structure? a. Right subclavian artery b. Right atrium c. Right subclavian vein d. Superior vena cava - ANS: C The right lymphatic duct drains lymph into the right subclavian vein only.
3. A patient had a motor vehicle crash and suffered critical injuries to the brainstem. What physiological responses would the healthcare professional expect to see? a. Prolonged QRS segment b. Shortened PR interval c. Pulse and blood pressure changes d. Fluid overload - ANS: C The major cardiovascular control center is in the brainstem in the medulla with secondary areas in the hypothalamus, the cerebral cortex, the thalamus, and the complex networks of exciting or inhibiting interneurons (connecting neurons) throughout the brain. The brainstem specifically controls blood pressure and pulse, so a severe injury to this area would manifest with changes in blood pressure and pulse. Changes on the ECG and fluid overload would not occur due to this injury.
4. What is an expected change in the cardiovascular system that occurs with aging? a. Arterial stiffening b. Decreased left ventricular wall tension c. Decreased aortic wall thickness d. Arteriosclerosis - ANS: A Arterial stiffening occurs with aging even in the absence of clinical hypertension. Aging is not responsible for the other conditions.
5. What is the major determinant of the resistance that blood encounters as it flows through the systemic circulation? a. Volume of blood in the systemic circulation b. Muscle layer of the metarterioles c. Muscle layer of the arterioles

c. Substances pass between vesicles by active transport across the endothelial cell membrane. d. Substances pass across the endothelial cell membrane by osmosis. e. Substances pass through endothelial cell membranes by diffusion. - ANS: A, B, C, E Substances pass between the capillary lumen and the interstitial fluid in several ways: (1) through junctions between endothelial cells, (2) through fenestrations in endothelial cells, (3) in vesicles moved by active transport across the endothelial cell membrane, or (4) by diffusion through the endothelial cell membrane.