Chapter 29: Structure and Function of the Cardiovascular System

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

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

A nurse is evaluating a client to determine the effectiveness of medications given to reduce left ventricular afterload. Which hemodynamic parameter is most appropriate for the nurse to monitor?

Systemic vascular resistance (SVR) Afterload is resistance to ejection of blood from the heart. Resistance is the opposition to flow caused by friction between the moving blood and the stationary vessel wall. In the peripheral circulation, the collective resistance of all the vessels in that part of the circulation is referred to as the peripheral vascular resistance (PVR) or, sometimes, as the systemic vascular resistance.

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."

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?

45 to 50 beats/minute The AV nodal fibers, when not stimulated, discharge at an intrinsic rate of 45 to 50 times a minute, and the Purkinje fibers discharge 15 to 40 times/minute. The SA node has the fastest intrinsic rate of firing (60-100 beats/minute) and normally functions as the pacemaker of the heart. Should the SA node fail to discharge, the AV node can assume the pacemaker function of the heart, and the Purkinje system can assume the pacemaker function of the ventricles should the AV junction fail to conduct impulses from the atria to the ventricles.

Which client is most likely to be experiencing vasodilation?

A 51-year-old man with a history of hypertension who is taking a medication that blocks the effect of the renin--angiotensin--aldosterone system. Angiotensin is a potent vasoconstrictor, and medications that block this induce vasodilation. Epinephrine is also a vasoconstrictor. Histamine is a vasodilator, so antihistamine medications are likely to induce vasoconstriction. Serotonin is a vasoconstrictor, so medications that block its reuptake and increase free levels are apt to promote vasoconstriction. (less)

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

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 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.

The circulatory system can be divided into two parts. What does the systemic circulation include? Select all that apply.

Aorta Capillaries

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

The heart controls the direction of blood flow. What is the role of the aortic valve?

Controls the direction of blood flow from the left side of the heart to the systemic circulation The heart valves control the direction of blood flow from the atria to the ventricles (the AV valves), from the right side of the heart to the lungs (pulmonic valves) and from the left side of the heart to the systemic circulation (aortic valve). (less)

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

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

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

Histamine 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.

A nurse is caring for a client following surgery. The central venous pressure (CVP) monitor indicates low pressures. Which action is a priority for the nurse to take?

Increase the IV fluid infusion per protocol. Systemic veins flow into the right atrium of the heart; the pressure in the right atrium is called the central venous pressure (CVP). Right atrial pressure is regulated by the ability of the right ventricle to pump blood into the lungs and the tendency of blood to flow from the peripheral veins into the right atrium. The normal right atrial pressure is about 0 mm Hg, which is equal to atmospheric pressure. A low CVP indicates hypovolemia and a need for an increase in the IV infusion rate. (less)

Which of the following statements are true regarding the parasympathetic nervous system and its effect on the cardiac system? Select all that apply.

It innervates the heart. Its effects are facilitated by the vagus nerve Bradycardia is a result of this system. Both the parasympathetic and sympathetic nervous systems innervate the heart. The vagus nerve, with increased vagal activity producing a slowing of heart rate. 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. (less)

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

Laminar 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).

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

Pulmonary Aortic

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

Pumps blood to the lungs

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. 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. (less)

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

Stroke volume

The nurse identifies the blood vessel layer that constricts to regulate and control diameter as which of the following?

Tunica media

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

Venous blood return 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.

The cardiac cycle describes the pumping action of the heart. Which statement is correct about systole?

Ventricles contract and blood is ejected from the heart.

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 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.