Chapter 17 Practice
A client who lives with angina pectoris has taken a sublingual dose of nitroglycerin to treat the chest pain he experiences while mowing his lawn. This drug facilitates release of nitric oxide, which will have what physiologic effect? A) Smooth muscle relaxation of vessels B) Decreased heart rate and increased stroke volume C) Increased preload D) Reduction of cardiac refractory periods
A.
Preload represents the volume work of the heart and is largely determined by: A) Venous blood return B) Vascular resistance C) Force of contraction D) Ventricular emptying
A.
A client has entered hypovolemic shock after massive blood loss in a car accident. Many of the client's peripheral blood vessels have consequently collapsed. How does the Laplace law account for this pathophysiologic phenomenon? A) Blood pressure is no longer able to overcome vessel wall tension. B) Decreasing vessel radii has caused a decrease in blood pressure. C) Wall thickness of small vessels has decreased due to hypotension. D) Decreases in wall tension and blood pressure have caused a sudden increase in vessel radii.
A. In circulatory shock, there is a decrease in blood volume and vessel radii, along with a drop in blood pressure. As a result, many of the small vessels collapse as blood pressure drops to the point where it can no longer overcome the wall tension. Decreases in vessel wall radii do not cause the decrease in blood pressure, and wall thickness generally remains static.
A client asks why he has not had major heart damage since his cardiac catheterization revealed he has 98% blockage of the right coronary artery. The nurse's best response is: A) "You must have been taking a blood thinner for a long time." B) "You have small channels between some of your arteries, so you can get blood from a patent artery to one severely blocked." C) "You are just a lucky person since most people would have had a massive heart attack by now." D) "With this amount of blockage, your red blood cells get through the vessel one-by-one and supply oxygen to the muscle."
B.
A client with a diagnosis of secondary hypertension has begun to experience signs and symptoms that are consistent with decreased cardiac output. Which of the following determinants of cardiac output is hypertension most likely to affect directly? A) Preload B) Afterload C) Contractility D) Heart rate
B.
Following a hypertensive crisis, a client's family asks, "Why are the client's eyes so bloodshot?" The nurse responds that high arterial pressure: A) From straining to have a bowel movement can rupture small vessels in the eyes B) Damages more fragile blood vessels like those in the eyes to the point of rupture C) Can interfere with clotting factor production, so clients bleed more easily D) Cause heart muscle to pump stronger, sending too much blood to small vessels in the eyes
B.
A client with a history of heart failure has been referred for an echocardiogram. Results of this diagnostic test reveal the following findings: heart rate 80 beats/minute; end-diastolic volume 120 mL; and end-systolic volume 60 mL. What is this client's ejection fraction? A) 200 mL B) 50% C) 0.80 D) 180 mL
B. 50% of 120 = 60
When discussing the AV node's role in the electrical conduction of the heart with a client newly diagnosed with an AV block, which of the following statements are accurate? Select all that apply. A) The AV node offers a two-way conduction area between the atria and the ventricles. B) The velocity of conduction through the AV junctional fibers is very fast, which greatly increases impulse transmission. C) A block at the AV bundle of His interferes with the normal delay of the impulse, thereby interfering with complete ejection of blood from the atria prior to ventricular contraction. D) When there is an AV block, impulses from the atria and ventricles beat independently of each other so, the heart rhythm is usually chaotic and not regular.
C, D.
A client has had a myocardial infarction (MI) that damaged the right atrium, which has interfered with the SA node. The compensatory mechanism, the AV node, becomes the pacemaker of the heart and beats how many times/minute? A) 10 to 20 beats/minute B) 21 to 30 beats/minute C) 45 to 50 beats/minute D) 55 to 60 beats/minute
C.
A large increase in heart rate can cause: A) Increased blood viscosity B) Loss of action potential C) Decreased stroke volume D) Reduced cardiac contractility
C.
A male client with a history of angina has presented to the emergency department with uncharacteristic chest pain, and his subsequent ECG reveals T-wave elevation. This finding suggests an abnormality with which of the following aspects of the cardiac cycle? A) Atrial depolarization B) Ventricular depolarization C) Ventricular repolarization D) Depolarization of the AV node
C.
During ventricular systole, closure of the atrioventricular (AV) valves coincides with: A) Atrial chamber filling B) Aortic valve opening C) Isovolumetric contraction D) Semilunar valves opening
C.
Following a kitchen accident with a knife, the client's cut has experienced a decrease in the amount of bleeding and has developed a clot. The nurse knows this is primarily a result of humoral control of blood flow with the release of: A) Histamine B) Bradykinin C) Serotonin D) Prostaglandin E2
C.
The parasympathetic nervous system causes a slowing of the heart rate by increasing: A) Norepinephrine B) Vessel constriction C) Cardioinhibitory center D) Smooth muscle tone
C.
Heart muscle differs from skeletal muscle tissue by being able to generate: A) Contractions B) Calcium influx C) Action potentials D) Sarcomere binding
C. Heart muscle, or the myocardium, is unique among other muscles in that it is capable of generating and rapidly conducting its own electrical impulses or action potentials. These action potentials result in excitation of muscle fibers throughout the myocardium. Similarities to skeletal muscle include contractility, calcium influx, and actin-myosin (sarcomeres) binding.
Hypoxia is said to have a negative inotropic effect on the heart, which means: A) The heart rate will slow down, so the atria and ventricles can fill better. B) The cardiac output will decrease to cause less work for the heart. C) The heart will adjust so that less time will be spent in diastole and filling of the ventricles will shorten. D) There will be interference in the generation of ATP, which is needed for muscle contraction
D.
If the parasympathetic neurotransmitter releases acetylcholine, the nurse should anticipate observing what changes in the ECG pattern? A) Heart rate 150 beats/minute, labeled as supraventricular tachycardia B) Disorganized ventricular fibrillation C) Complete cardiac standstill D) Slowing of heart rate to below 60 beats/minute
D.
Following several weeks of increasing fatigue and a subsequent diagnostic workup, a client has been diagnosed with mitral valve regurgitation. Failure of this heart valve would have which of the following consequences? A) Backup of blood from the right atrium into the superior vena cava B) Backflow from the right ventricle to the right atrium during systole C) Inhibition of the SA node's normal action potential D) Backflow from the left ventricle to the left atrium
D. The mitral valve separates the left ventricle from the left atrium; failure of this valve would cause backflow from the former to the latter during systole. Valve function does not directly affect cardiac contractility.
A heart failure client has an echocardiogram performed revealing an ejection fraction (EF) of 40%. The nurse knows this EF is below normal and explains to the client: A) "This means you have a lot of pressure built-up inside your heart." B) "This means your heart is not pumping as much blood out of the heart with each beat." C) "You need to increase the amount of exercise you do to get your heart muscle back in shape." D) "Your ventricular muscle is getting too stiff to beat normally."
B.
When explaining a new diagnosis of complete heart block to a client/family, the nurse should include which of the following statements? A) "This means that your atria are not contracting normally, they are quivering." B) "One consequence of this type of block is a very slow heart rate that limits circulation to the brain." C) "This type of arrhythmia requires defibrillation, which will occur in the cardiac catheter lab later today." D) "It's pretty common for everyone to experience this arrhythmia, especially during times of stress in their lives."
B.
Which of the following statements about calcium channel-blocking (CCB) drugs is accurate? A) Since CCB drugs work the a-adrenergic receptors to open the channels, vasoconstriction occurs. B) CCB drugs work on b-adrenergic receptors to close the channels, so vasodilation occurs. C) CCB drugs prevent reabsorption of calcium in the kidneys and therefore can lower serum calcium levels. D) CCB drugs cause smooth muscle contraction, thereby allowing more blood to be stored in veins.
B.
In the days following a tooth cleaning and root canal, a client has developed an infection of the thin, three-layered membrane that lines the heart and covers the valves. What is this client's most likely diagnosis? A) Pericarditis B) Endocarditis C) Myocarditis D) Vasculitis
B. The endocardium is a thin, three-layered membrane that lines the heart and covers the valves; infection of this part of the heart is consequently referred to as endocarditis.
Which of the following statements about vascular compliance is accurate? A) Arteries are much more distensible than veins. B) Veins can act as a reservoir for storing large quantities of blood. C) Arteries have thick muscular walls that constrict tightly, thereby ejecting blood without storing it for later use. D) A continuous flow through the capillaries occurs primarily during systole.
B. The most distensible of all vessels are the veins, which can increase their volume with only slight changes in pressure, allowing them to function as a reservoir for storing large quantities of blood that can be returned to the circulation when it is needed. Although arteries have a thicker muscular wall than veins, their distensibility allows them to store some of the blood that is ejected from the heart during systole, providing for continuous flow through the capillaries as the heart relaxes during diastole.
Upon admission assessment, the nurse hears a murmur located at the fifth intercostal space, midclavicular line. The client asks, "What does that mean?" The nurse will base her answer on which of the following physiologic principles? A) "You have been exposed to an infection that went into your blood stream." B) "You have a heart valve that is diseased." C) "You heart has been pumping your blood so hard, that the pressure has damaged your valves." D) "Your heart has enlarged, so naturally your valves had to enlarge as well."
B. Turbulence is often accompanied by vibrations of the blood and surrounding cardiovascular structures. Some of these vibrations are in the audible range and can be heard using a stethoscope. For example, a heart murmur results from turbulent flow through a diseased heart valve. The other distractors are not feasible.
A client is diagnosed with an abdominal aortic aneurysm that the physician just wants to "watch" for now. When teaching the client about signs/symptoms to watch for, the nurse will base the teaching on which of the following physiological principles? A) Small diameter of this vessel will cause it to rupture more readily. B) The larger the aneurysm, the less tension placed on the vessel. C) As the aneurysm grows, more tension is placed on the vessel wall, which increases the risk for rupture. D) The primary cause for rupture relates to increase in abdominal pressure such as straining to have a bowel movement.
C. Because the pressure is equal throughout, the tension in the part of the balloon with the smaller radius is less than the tension in the section with the larger radius. The same holds true for an arterial aneurysm in which the tension and risk of rupture increase as the aneurysm grows in size. Wall tension is inversely related to wall thickness, such that the thicker the vessel wall, the lower the tension, and vice versa. Although arteries have a thicker muscular wall than veins, their distensibility allows them to store some of the blood that is ejected from the heart during systole providing for continuous flow through the capillaries as the heart relaxes during diastole.
