Pathophysiology chapter 17 Control of Cardiovasvular Function
The heart controls the direction of blood flow. What is the role of the aortic valve? a.) Controls the direction of blood flow from the ventricles to the artia b.) Controls the direction of blood flow from the left side of the heart to the systemic circulation
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). (p385)
The cardiologist just informed a patient that they have a reentry circuit in the electrical conduction system in their heart. This arrhythmia is called Wolff-Parkinson-White (WPW) syndrome. After the physician has left the room, the patient asks the nurse to explain this to them. Which of the following statements most accurately describes what is happening? a.) "For some reason, your electrical system is not on full charge so they will have to put in new leads and a pacemaker to make it work better." b.) "There is an extra, abnormal electrical pathway in the heart that leads to impulses traveling around the heart very quickly, in a circular pattern, causing the heart to beat too fast."
Correct response: "There is an extra, abnormal electrical pathway in the heart that leads to impulses traveling around the heart very quickly, in a circular pattern, causing the heart to beat too fast." There are several forms of reentry. The first is anatomic reentry. It involves an anatomic obstacle around which the circulating current must pass and results in an excitation wave that travels in a set pathway. Arrhythmias that arise as a result of anatomic reentry are paroxysmal supraventricular tachycardias, as seen in WPW syndrome, atrial fibrillation, atrial flutter, etc. A=sinus node arrhythmias and SSS. B=arrhythmias caused by MI. D= third degree block or ventricular standstill, for example. (p389)
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. (p 399)
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). (p378)
The heart is a four-chambered pump. What is the function of the right ventricle?
Pumps blood to the lungs 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. (p376)
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 The cardiac output (CO) is a product of the stroke volume and the heart rate (HR) and can be expressed as CO = SV × HR. (p392)
Which of the following vessel layers is made primarily of muscle?
Tunica Media 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. (p394)
A male patient with a history of angina has presented to the emergency department with uncharacteristic chest pain. His subsequent electrocardiogram (ECG) reveals T-wave elevation. This finding suggests an abnormality with which of the following aspects of the cardiac cycle?
Ventricular repolarization The T wave on an 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. (p390)
The nurse is reviewing the circulatory system. Which statements are correct about the functional organization of the circulatory system? Select all that apply. a.) The arterial system distributes oxygenated blood to the tissues. b.) The venous system collects deoxygenated blood from the tissues
a, b 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. (p394)
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) A membranous sac that encloses the heart b) The outer muscular layer of the heart c) The innermost lining of the heart chambers d) The electrical conduction system of the heart
a.) 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. (p382)
ECG monitoring has been found to be more sensitive than a client's report of symptoms when identifying transient ongoing myocardial ischemia. Why is this? a.)The ECG can look at ischemic events from different directions. b.) Most ECG-detected ischemic events are clinically silent.
b.) Most ECG-detected ischemic events are clinically silent. Persons with acute coronary syndrome are at risk for developing extension of an infarcted area, ongoing myocardial ischemia, and life-threatening arrhythmias. Research has revealed that 80% to 90% of ECG-detected ischemic events are clinically silent. Thus, ECG monitoring is more sensitive than a client's report of symptoms for identifying transient ongoing myocardial ischemia. (p456)
Which of the following arrhythmias is considered to be the most fatal and requires immediate treatment? a) Premature ventricular contractions b) Ventricular fibrillation c) Premature atrial contractions d) Atrial flutter
b.) Ventricular fibrillation Ventricular fibrillation represents severe derangements of cardiac rhythms that terminate fatally within minutes unless corrective measures are taken promptly. All of the other arrhythmias need to have further investigation into etiology, but are not immediately fatal. (p389)
A client is admitted to the hospital with severe bradycardia, heart rate in low to upper 40s, after contracting Lyme disease. She asks the nurse why the heart rate is so slow. The most accurate response would be a possible disassociation between the atria and ventricles due which of the following? a) Inflammation of the SA node b) SA node excitation c) AV nodal block d) Purkinje system block
c.) AV nodal block Disassociation between the atria and ventricles interrupts the communication between them and they each beat with their own different regular rates. Therefore an AV nodal block would cut off communication between the atria and ventricles causing the area below the AV node to pace the ventricles. When this disassociation occurs and the heart rate is 40 to 60 per minute the block is typically proximal to the bundle of his. (p389)
When trying to explain to a new dialysis patient the movement of substances through the capillary pores, the nurse will explain that in the kidneys, the glomerular capillaries have: a) Large pores so that substances can pass easily through the capillary wall. b) No capillary openings since this would lead to extensive hemorrhage. c) Small openings that allow large amounts of smaller molecular substances to filter through the gomeruli. d) Endothelial cells that are joined by tight junctions that form a barrier to medication filtration.
c.) Small openings that allow large amounts of smaller molecular substances to filter through the gomeruli. The glomerular capillaries in the kidneys have small openings called fenestrations that pass directly through the middle of the endothelial cells. This allows large amounts of small molecular and ionic substances to filter through the glomeruli without having to pass through the clefts between the endothelial cells. (p396)
A patient's electrocardiogram monitor begins to sound an alarm and shows sustained ventricular fibrillation. The patient is unconscious and without a pulse. Which of the following priority interventions should the nurse take? a) Administer IV push atropine b) Notify the patient's attending physician c) Perform synchronized cardioversion d) Defibrillate the patient
d.) Defibrillate the patient Immediate defibrillation using a nonsynchronized, direct-current electrical shock is mandatory for ventricular fibrillation and for ventricular flutter that has caused loss of consciousness. (p389)
