Chapter 29: Structure and Function of the Cardiovascular System

Valves in the veins prevent retrograde flow. In which veins are there no valves? Select all that apply

- Abdominal -Thoracic Explanation: There are no valves in the abdominal or thoracic veins. Therefore, pressure in the abdominal and thoracic cavities heavily influence blood flow in these veins. pg. 729

Which of the following is the correct sequence for blood flow through the heart?

-Right atrium - tricuspid valve - right ventricle - pulmonary artery - lungs - pulmonary vein - left atrium - mitral valve - left ventricle - aorta Explanation: The correct pathway for blood flow through the heart is the right atrium - tricuspid valve - right ventricle - pulmonary artery - lungs - pulmonary vein - left atrium - mitral valve - left ventricle - aorta. pg. 713

The circulatory system is divided into two parts. What does the pulmonary circulation include? Select all that apply.

-Right heart -Pulmonary artery - Pulmonary veins Explanation: The pulmonary circulation consists of the right heart, the pulmonary artery and the pulmonary veins. The systemic circulation includes the aorta, left side of heart, and vena cava. pg. 713

In which situation is blood most likely to be rapidly relocated from central circulation to the lower extremities?

- A client is helped out of bed and stands up Explanation: During a change in body position, blood is rapidly relocated from the central circulation (when the client is recumbent) to the lower extremities (when the client stands up). This results in a temporary drop in blood pressure known as postural hypotension and reflects the redistribution of blood in the body. pg. 714

Preload represents the volume work of the heart and is largely determined by:

- Venous blood return Explanation: Preload represents the amount of blood the heart must pump with each beat and represents the volume of blood stretching the ventricular muscle fibers at the end of diastole. Pressure (resistance), contraction, and ventricular emptying relate to afterload. pg. 726

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?

- Ventricular repolarization Explanation: The T wave on electrocardiography (ECG) corresponds to ventricular repolarization. Atrial depolarization is represented by the P wave and ventricular depolarization by the QRS complex. The isoelectric or zero line between the P wave and the Q wave represents depolarization of the AV node, bundle branches, and Purkinje system. pg. 723

The heart consists of four valves. Which are the semilunar values? Select all that apply.

- Pulmonary - Aortic Explanation: The heart's atrioventricular valves are the tricupsid and the mitral. The heart's semilunar valves are the pulmonary and aortic values. pg. 721

A nurse is caring for a client with right heart failure caused by pulmonary hypertension. Which hemodynamic parameter is most appropriate for the nurse to monitor?

- Pulmonary arterial pressure (PAP) Explanation: The pulmonary arterial pressure is the main source of afterload work on the right heart. pg. 726

A client is admitted to the cardiac unit with a diagnosis of pericarditis. The nurse is teaching the patient about the anatomical location of the infection. The nurse evaluates the effectiveness of the teaching when the client correctly identifies which of the following as the location of the pericardium?

- A membranous sac that encloses the heart Explanation: The pericardium forms a fibrous covering around the heart, holding it in a fixed position in the thorax and providing physical protection and a barrier to infection. The pericardium is a tri-layer sac consisting of a tough, outer fibrous layer and a thin, inner serous layer. pg. 719

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?

- Backflow from the left ventricle to left atrium Explanation: 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. pg. 721

A client's echocardiogram identified a narrowed valve that has resulted in a decreased blood flow between the left atria and left ventricle. The nurse would interpret this as the:

- Bicuspid valve Explanation: The bicuspid valve, (also called the mitral) controls the flow of blood between the left atria and left ventricle. The aortic valve controls flow between the left ventricle and aorta. The tricuspid controls the flow between the right atria and ventricle. The pulmonic valve controls flow between the right ventricle and pulmonary artery. pg.721

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?

- Blood pressure is no longer able to overcome vessel wall tension. Explanation: 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. pg. 718

Which of the following blood vessels function without the benefit of having walls comprised of three muscular layers?

- Capillaries Explanation: The capillaries are small, thin-walled vessels that link the arterial and venous sides of the circulation and allow the exchange of oxygen and metabolites generated by the various tissues. The walls of all blood vessels, except the capillaries, are composed of three layers: tunica externa, tunica media, and tunica intima. pg. 714

Select the correct sequence of blood return to the heart.

- Capillaries, venules, veins, right atrium Explanation: The correct pathway for blood returning back to the heart is the capillaries, venules, veins, and right atrium. pg. 713

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?

- Endocarditis Explanation: 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. pg. 719

The school nurse is doing a health class on the functional organization of the circulatory system. What is the function of the capillaries in the circulatory system?

- Exchange gases, nutrients and wastes Explanation: The circulatory system consists of the heart which pumps blood, the arterial system which distributes oxygenated blood to the tissues, the venous system which collects deoxygenated blood from the tissues and returns it to the heart, and the capillaries where exchange of gases, nutrients and waste takes place. pg. 713

Humoral control of blood flow involves the effect of vasodilator and vasoconstrictor substances in the blood. Select the factor that has a powerful vasodilator effect on arterioles and increases capillary permeability.

- Histamine Explanation: Histamine has a powerful vasodilator effect on arterioles and has the ability to increase capillary permeability, allowing leakage of both fluid and plasma proteins into the tissues. Norepinephrine is a powerful vasoconstrictor. Serotonin causes vasoconstriction and plays a major role in control of bleeding. Prostaglandins produce either vasoconstriction or vasodilatation. pg.731

A grandmother, a cook at a nearby school, was recently hospitalized when she lost an extensive amount of blood in a work-related accident. The grandmother tells the nurse that she heard that she would keep feeling faint until the brain made more blood. The nurse knows that when the blood pressure dropped, the pressure in the carotid arteries decreased. This was detected by baroreceptors in the carotid arteries. What did the baroreceptors do?

- Increase sympathetic stimulation of the heart and blood vessels Explanation: The baroreceptors in the carotid arteries increase sympathetic stimulation, not parasympathetic, of the heart and blood vessels. The baroreceptors do not stimulate the brain to form new red blood cells or inhibit renin release from the kidneys to promote fluid retention. pg. 736

A client has experienced sympathetic nervous stimulation of the heart. The nurse is aware that the client may manifest which of the following?

- Increased heart rate and increased contractility Explanation: The sympathetic nervous system has an excitatory influence on heart rate and contractility, and it serves as the final common pathway for controlling the smooth muscle tone of the blood vessels. With stimulation, both heart rate and contractility would increase. pg. 737

Which factor can cause turbulent blood flow?

- Increased velocity Explanation: Under some conditions, blood flow switches from laminar flow (blood component layering) to turbulent flow. Turbulence can result from an increase in velocity of flow, a decrease in vessel diameter, or low blood viscosity. Vessel length affects the rate of flow rather than the type of flow. pg. 717

A nursing instructor is explaining arterial circulation to a group of nursing students. Which is the most appropriate information about arterial pressure gradient in arterial side of systemic circulation for the nurse to provide?

- It contains one sixth of the total blood volume. Explanation: The arterial side of the circulation contains approximately one sixth of the blood volume. Arterial circulation exerts much greater than the pressure on the venous side of the circulation. The venous side contains approximately two thirds of the blood. Because of their thicker, muscular walls arteries are less distensible than veins. pg. 714

Which of the following is true regarding pulmonary circulation?

- It is a low-pressure system that allows for improved gas exchange. Explanation: The pulmonary circulation consists of the right heart and the pulmonary artery, capillaries, and veins. It is the smaller of the systems and functions at a lower pressure to assist with gas exchange. pg. 713

Which of the following blood flow patterns reduces friction, allowing the blood layers to slide smoothly over one another?

- Laminar Explanation: Laminar blood flow reduces friction by allowing the blood layers to slide smoothly over one another, with the axial layer having the most rapid rate of flow. Axially, crosswise, and turbulent blood flow would result in increased friction. In turbulent flow, the laminar stream is disrupted and the flow becomes mixed, moving radially (crosswise) and axially (lengthwise). pg. 717

When the semilunar valves open it signals the onset of the ejection period. The aortic pressure reflects changes in the ejection of blood from which part of the heart?

- Left ventricle Explanation: The aortic pressure reflects changes in the ejection of blood from the left ventricle, not the right ventricle or atrium. pg. 724

Nitroglycerin is the drug of choice in treating angina. What does nitroglycerin release into the vascular smooth muscle of the target tissues?

- Nitric oxide Explanation: The fact that nitric oxide is released into the vessel lumen (to inactivate platelets) and away from the lumen (to relax smooth muscle) suggests that it protects against both thrombosis and vasoconstriction. Nitroglycerin, which is used in treatment of angina, produces its effects by releasing nitric oxide in vascular smooth muscle of the target tissues. None of the other options are released by nitroglycerin. pg. 731

Which of the following factors represents the amount of blood that the heart must pump with each beat and is determined by the stretch of the cardiac muscle fibers and the actions of the heart prior to cardiac contraction?

- Preload Explanation: Preload is the distending force that stretches the heart muscle just prior to the work of the onset of ventricular contraction. It represents the volume of blood stretching the ventricular muscle fibers at the end of diastole (i.e., end-diastolic volume) and is the sum of the blood remaining in the heart at the end of systole (end-systolic volume) and the venous return to the heart. pg. 726

Which of the following factors affect cardiac performance? Select all that apply.

- Preload -Afterload - Myocardial contractility Explanation: The four factors that affect cardiac performance include preload, afterload, myocardial contractility, and heart rate; not heart rhythm. pg. 726

A nurse is teaching a client the correct technique for taking an arterial pulse. The nurse explains that the pulsations are:

- Pressure pulses Explanation: The arterial pressure pulse represents the energy that is transmitted from molecule to molecule along the length of the vessel. When taking a pulse, it is the pressure pulses that are felt. Pressure pulses have no direct relation to the blood flow. It is the pressure pulses that produce the Korotkoff sounds heard during blood pressure measurement. Pressure pulses would be felt even if there was no blood flow at all. pg. 729

Colloidal osmotic pressure acts differently than the osmotic effects of the plasma proteins. What is its action?

- Pulls fluid back into the capillary Explanation: The osmotic pressure caused by the plasma proteins in the blood tends to pull fluid from the interstitial spaces back into the capillary. This pressure is termed colloidal osmotic pressure to differentiate the osmotic effects of the plasma proteins, which are suspended colloids, from the osmotic effects of substances such as sodium and glucose, which are dissolved crystalloids. pg.734

The heart is a four-chambered pump. What is the function of the right ventricle?

- Pumps blood to the lungs Explanation: The right atrium receives blood returning to the heart from the system circulation. The left atrium receives oxygenated blood from the lungs. The right ventricle pumps blood to the lungs. The left ventricle pumps blood into the systemic circulation. pg. 723

The electrical activity of the heart is recorded on the ECG. What does the T wave on the ECG represent?

- Repolarization of the ventricles Explanation: The P wave represents the depolarization of the sinoatrial node. The QRS complex represents the depolarization of the ventricles. The T wave represents repolarization of the ventricles, not the atrium. pg. 723

A client has had an acute myocardial infarction. The brother of the client has a history of angina. The client asks how they will know if the brother's pain is angina or if the brother is actually having an MI. Which statement is correct?

- Rest and intake of nitroglycerin relieve chest pain with angina; they do not relieve chest pain with an MI. Explanation: Rest and intake of nitroglycerin relieve chest pain with angina but not with an MI. Pain with angina and MI is an subjective symptom for each client. Pain with angina and MI can occur at a variety of times. pg. 731

A client has prominent jugular veins. What type of medical problem is associated with prominent jugular veins?

- Right sided heart failure Explanation: Right sided heart failure, not left sided heart failure, shock, or cerebral vascular accident, is seen with prominent jugular veins. pg. 723

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 the release of which humoral factor?

- Serotonin Explanation: Serotonin release causes vasoconstriction of blood vessels and plays a major role in the control of bleeding. Histamine, bradykinin, and prostaglandin E2 cause vasodilation of blood vessels. pg. 731

A nurse is explaining the conduction system of the heart to a client who is experiencing an arrhythmia. Which would be the most appropriate explanation?

- Sinoatrial node (SA), internodal pathways, AV node, AV bundle, Purkinje fibers Explanation: The conduction system consists of the SA node, the internodal pathways, the AV node, the AV bundle, and the Purkinje fibers. The other options are not normal conduction patterns. pg. 845-846

If the parasympathetic neurotransmitter releases acetylcholine, the nurse should anticipate observing what changes in the ECG pattern?

- Slowing of heart rate to below 60 beats/minute Explanation: Acetylcholine, the parasympathetic neurotransmitter released during vagal stimulation of the heart, slows down the heart rate by decreasing the slope of phase 4. The catecholamines, the sympathetic nervous system neurotransmitters epinephrine and norepinephrine, increase the heart rate by increasing the slope or rate of phase 4 depolarization. Fibrillation is the result of disorganized current flow within the ventricle (ventricular fibrillation). Fibrillation interrupts the normal contraction of the atria or ventricles. In ventricular fibrillation, the ventricles quiver but do not contract. Thus, there is no cardiac output, and there are no palpable or audible pulses (i.e., cardiac standstill). pg. 417-418

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?

- Smooth muscle relaxation of vessels Explanation: Nitroglycerin produces its effects by releasing nitric oxide in vascular smooth muscle of the target tissues, resulting in relaxation of this muscle and increased blood flow. This drug does not decrease heart rate. Because it vasodilates, it decreases preload. Nitroglycerine does not affect cardiac refractory periods. pg. 730

Which of the following is the difference between the end-diastolic and end-systolic volumes?

- Stroke volume Explanation: Stroke volume is determined by the difference between end-diastolic and end-systolic volumes. Cardiac output is determined by stroke volume and heart rate. Ejection fraction is the volume ejected from the left ventricle. Cardiac reserve is determined by cardiac output. pg. 725

The health care provider is concerned that a client has developed a decrease in cardiac output. Cardiac output may be calculated as:

- Stroke volume × heart rate Explanation: The cardiac output (CO) is a product of the stroke volume and the heart rate (HR) and can be expressed as CO = SV × HR. pg. 725

The nurse is reviewing the circulatory system. Which statements are correct about the functional organization of the circulatory system? Select all that apply.

- The arterial system distributes oxygenated blood to the tissues. -The venous system collects deoxygenated blood from the tissues . Explanation: The circulatory system consists of the heart which pumps blood, the arterial system which distributes oxygenated blood to the tissues, the venous system which collects deoxygenated blood from the tissues and returns it to the heart, and the capillaries where exchange of gases, nutrients and waste takes place. pg. 713

During an assessment of a client with ankle swelling, the nurse observes jugular venous pulsations 5 cm above the sternal angle when the head of his bed is elevated 45 degrees. Which of the following is the correct interpretation of this finding?

- The client has increased pressure related to right heart failure. Explanation: The jugular veins are normally flat or collapsed. Since there are no valves at the atrial sites (i.e., venae cavae and pulmonary veins) where blood enters the heart they can become prominent in severe right-sided heart failure. This means that excess blood is pushed back into the veins when the atria become distended. pg. 723

Downstream peripheral pulses have a higher pulse pressure because the pressure wave travels faster than the blood itself. What occurs in peripheral arterial disease?

- The pulse decreases rather than increases in amplitude. Explanation: With peripheral arterial disease, there is a delay in the transmission of the reflected wave so that the pulse decreases rather than increases in amplitude. pg. 729

Which of the following related circulatory complications can result from surgical treatment for metastatic breast cancer?

-Lymphedema in the affected arm Explanation: Involvement of lymphatic structures by malignant tumors and removal of lymph nodes at the time of cancer surgery are common causes of lymphedema. The other options are not related to the surgery that would have removed any affected lympth nodes. pg. 735

A cardiac nurse is describing to a colleague the relationship between the law of Laplace and a client's peripheral vascular disease. To express the law of Laplace in an equation, the nurses need to know which values? Select all that apply.

- The tension that exists in the walls of a blood vessel -The radius of a particular blood vessel - The pressure that exists in the lumen of a vessel Explanation: The law of Laplace is determined by the equation, P = T/r, in which T is wall tension, P is the intraluminal pressure, and r is vessel radius. The client's stroke volume is not directly relevant to the equation. The thickness of a vessel will affect wall tension, but this is not an explicit component of the equation.: pg. 718

Hypoxia is said to have a negative inotropic effect on the heart, which means:

- There will be interference in the generation of ATP, which is needed for muscle contraction. Explanation: An inotropic influence is one that modifies the contractile state of the myocardium independent of the Frank-Starling mechanism. Hypoxia exerts a negative inotropic effect by interfering with the generation of ATP, which is needed for muscle contraction. Hypoxia does not directly slow the heart rate, decrease cardiac output, or interfere with filling times. However, these can develop if the ability of the muscle to contract becomes severe and is not treated promptly. pg. 726

The heart consists of four valves. Which are the heart's atrioventricular valves? Select all that apply.

- Tricuspid - Mitral Explanation: The heart's atrioventricular valves are the tricupsid and the mitral. The semilunar valves are the pulmonary and aortic. pg. 721

The troponin complex is one of a number of important proteins that regulate actin-myosin binding. Troponin works in striated muscle to help regulate calcium-mediated contraction of the muscle. Which of the troponin complexes are diagnostic of a myocardial infarction?

- Troponin T and troponin I Explanation: In clinical practice, the measurement of the cardiac forms of troponin T and troponin I is used in the diagnosis of myocardial infarction. Troponin C is not diagnostic of a myocardial infarction. Troponin A is not one of the troponin complexes. pg. 720

Which of the following vessel layers is made primarily of muscle?

- Tunica media Explanation: The outermost layer of a vessel is called the tunica externa or tunica adventitia. The middle layer is largely a smooth muscle layer that constricts to regulate and control the diameter of the vessel. The innermost layer is the tunica intima. pg. 727

In the arterial-venous circulatory system, pressure is inversely related to which of the following?

- Volume Explanation: In the circulatory system, pressure is inversely related to volume. Arterial circulation contains a lower percentage of total blood volume and has higher pressure than the venous circulation, which contains the majority of circulating blood. Flow is related to viscosity and radius is related to wall tension. Velocity is inversely proportional to the cross-sectional area of the vessel. pg. 715

A nurse working with a client in heart failure is explaining why the symptoms of the heart failure were not evident for a long period of time. When describing the Frank--Starling mechanism, the nurse will explain:

- the relationship between venous return and stroke volume. Explanation: The Frank-Starling principle addresses the relationship between venous return and stroke volume. It does not directly address the characteristics of actin and myosin. The principle is unrelated to coronary circulation, chemoreceptors and baroreceptors. pg. 726

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:

-"You have small channels between some of your arteries, so you can get blood from a patent artery to one severely blocked." Explanation: Collateral circulation is a mechanism for the long-term regulation of local blood flow. In the heart, anastomotic channels exist between some of the smaller arteries. These channels permit perfusion of an area by more than one artery. When one artery becomes occluded, these anastomotic channels increase in size, allowing blood from a patent artery to perfuse the area supplied by the occluded vessel. For example, persons with extensive obstruction of a coronary blood vessel may rely on collateral circulation to meet the oxygen needs of the myocardial tissue normally supplied by that vessel. There is no indication that the client is on a blood thinner. pg.731

The heart is a four-chambered muscular pump. In one day, how many gallons of blood are pumped throughout the body?

-1800 Explanation: In one day, this pump moves more than 1800 gallons of blood throughout the body. pg. 719

Following a hypertensive crisis, a client's family asks, "Why are the client's eyes so bloodshot?" The nurse responds that high arterial pressure:

-Damages more fragile blood vessels like those in the eyes to the point of rupture Explanation: Excessively high arterial pressure and tissue perfusion can be dangerous because they may damage the more fragile blood vessels (like those inside the eyes). The myogenic control mechanisms rely on the stretch of the vascular smooth muscle in the vessel wall. Therefore, it has been proposed that when the arterial pressure stretches the vessel, this in turn causes reactive vascular constriction that reduces the blood flow nearly back to normal. pg. 727

Which of the following enzymes has a powerful vasodilator effect on arterioles and increases capillary permeability?

-Histamine Explanation: Histamine has a powerful vasodilator effect on arterioles and has the ability to increase capillary permeability, allowing leakage of both fluid and plasma proteins into the tissues. Serotonin causes vasoconstriction and plays a major role in control of bleeding. Prostaglandins produce either vasoconstriction or vasodilation. pg. 731