Porth's Chapter 25: Structure and Function of the Cardiovascular System

16. Which individual is MOST likely to be experiencing vasodilation? A. 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. B. A 9-year-old- boy who has been given an injection of epinephrine to preclude an anaphylactic reaction to a bee sting. C. A 30-year-old woman who takes antihistamines to treat her seasonal allergies. D. A 32-year-old man who takes a selective serotonin re-uptake inhibitor for treatment of depression.

Ans: A 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 re-uptake and increase free levels are apt to promote vasoconstriction.

4. A 72-year-old female has been told by her physician that she has a new heart murmur that requires her to go visit a cardiologist. Upon examination, the cardiologist informs the client that she has aortic stenosis. After the cardiologist has left the room, the client asks, "What caused the [aortic stenosis] to happen now?" The clinic nurse responds: A. "Heart murmurs result from tumultuous flow through a diseased heart valve that is too narrow and stiff. This flow causes a vibration called a murmur." B. "Aortic stenosis is commonly seen in older adult clients. Basically, there is a blockage in the valve that is causing blood to pool, causing decreased velocity of flow." C. "This is caused by a tear in one of the papillary muscles attached to the valve. They can do a procedure where they thread a catheter into the heart and reattach the muscle ends." D. "Because of the high amount of energy it takes to push blood through the aortic valve to the body, your valve just had to work too hard and it is weakening.

Ans: A Heart murmur results from turbulent flow through a diseased heart valve that may be narrow, too stiff, or too floppy. This turbulent flow causes a vibration called a murmur.

21. The nurse is assessing heart sounds on a client and detects a previously undocumented murmur. What diagnostic test should the nurse prioritize requesting an order for related to this finding? A. Hemoglobin B. Potassium C. Troponin D. Calcium

Ans: A The decreased viscosity that occurs with anemia can increase turbulent flow and create murmurs. Potassium and calcium imbalances can create alterations in heart rhythm and are not associated with heart murmurs. Troponin level indicates myocardial damage, which does not manifest as murmur.

1. As part of the preoperative teaching for clients who are about to undergo a coronary artery bypass graft, a nurse is performing an education session with a group of surgical candidates. Which teaching point BEST conveys an aspect of the human circulatory system? A. "The blood pressure varies widely between arteries and veins, and between pulmonary and systemic circulation." B. "Only around one-quarter of your blood is in you heart at any given time." C. "Blood pressure and blood volume roughly mimic one another at any given location in the circulatory system." D. "Left-sided and right-sided pumping action on each beat of the heart must equal each other to ensure adequate blood distribution."

Ans: A There is a large variation between the higher pressure in the systemic circulatory system and arteries and the lower pressure in the pulmonary system and veins. Approximately 8% of the blood supply is in the heart at any given time. Blood pressure and blood volume are inversely proportionate. The body is able to accommodate short-term differences in left-sided and right-sided output.

24. The nurse is caring for a client with peripheral edema. When elevating the client's legs to the level of the heart, what will the nurse expect to occur? Select all that apply. A. Reduction in the venous hydrostatic pressures of the legs B. Increase in urine output. C. Reduction in the venous colloid capillary pressures D. Increase in blood pressure E. Increase in arterial perfusion of the feet.

Ans: A, B, D Edema is fluid in the interstitial space; the movement of this fluid is dependent on the balance of hydrostatic and colloid pressures in the peripheral capillaries and interstitial space. When standing, the gravitational forces on the veins increases intravascular hydrostatic pressures, promoting filtration of fluid out of the capillary and into the intersitium. When the legs are elevated to the level of the heart, this intravascular hydrostatic pressure decreases, promoting reabsorption of the fluid due to a negative net filtration pressure. Once in the intravascular space, this fluid would increase preload, which would subsequently increase blood pressure. The fluid can now be filtered by the glomeruli, which would increase urine output. Elevating a limb can decrease arterial flow and will not affect colloid pressure, which is determined by circulating colloids such as albumin.

8. An 81-year-old female client of a long-term care facility has a history of congestive heart failure (CHF). The nurse practitioner caring for the client has positioned her siting up at an angle in bed and is observing her jugular venous distention. Why is jugular venous distention a useful indicator for the assessment of the client's condition? A. Increased cardiac demand causes engorgement of systemic blood vessels, of which the jugular vein is one of the largest. B. Blood backs up into the jugular vein because there are no valves at the point of entry into the heart. C. Peripheral dilation is associated with decreased stroke volume and ejection fraction. D. Heart valves are not capable of preventing back-flow in cases of atrial congestion.

Ans: B Because there are no valves at the entry points to the atria, congestion can result in engorgement of the jugular veins which are proximal to the heart. Increased cardiac demand is not associated with engorgement of vessels or peripheral dilation.

14. An emergency department client arrives after two days of "chest pressure" and "tightness" that was unrelieved with antacids. Following angioplasty for a massive myocardial infarction (MI), the client asks why so much muscle was damaged if only the left circumflex vessel was blocked. Which response by the nurse is the MOST accurate? A. "With any blockage in the heart, muscle damage always occurs." B. "If a major artery life the circumflex is occluded, the smaller vessels supplied by that vessel cannot restore the blood flow." C. "Since the circumflex artery supplies oxygenated blood flow to the posterior surface of the left ventricle, any amount of blockage will result in vital muscle tissue being lost." D. "When it comes to arteries in the heart, all vessels are equal and any blockage causes massive amount of damage that will not be restored."

Ans: B Hyperemia cannot occur when the arteries that supply the capillary beds are narrowed. For example, if a major coronary artery becomes occluded, the opening of channels supplied by that vessel cannot restore blood flow.

6. During an automobile accident where the client is bleeding heavily, which vascular component is the MOST distensible and can store large quantities of blood that can be returned to the circulation at this time of need? A. Liver and pancreas B. Kidneys C. Veins D. Aorta

Ans: C Compliance refers to the total quantity of blood that can be stored in a given portion of the circulation for each mm Hg rise in pressure. The most slight changes in pressure. This allows the veins to function as a reservoir for storing large quantities of blood that can be returned to the circulation when it is needed. Liver, pancreas, and kidneys are not vascular components.

18. A 51-year-old client, with a history of alcohol abuse and liver disease has low serum, levels of albumin, and presents with ascites (excess fluid in his peritoneal space) and jaundice. A health care professional would recognize that which process is most likely underlying his health problems? A. Low albumin is contributing to excess hydrostatic pressure and inappropriate fluid distribution. B. Low albumin is inducing hypertension and increase filtration of fluid into interstitial spaces. C. Insufficient albumin is causing insufficient absorption of fluid into the capillaries. D. Low albumin is contributing to an inability to counter gravitational effects.

Ans: C Deficits of plasma proteins like albumin result in insufficient amounts of fluid being absorbed into capillary circulation by osmotic pressure. It is not a result of hydrostatic pressure, hypertension, or the effects of gravity.

9. As part of their orientation to a cardiac care unit, a group of recent nursing graduates is receiving a refresher in cardiac physiology from the unit educator. Which teaching point BEST captures a component of cardiac function? A. "Efficient heart function requires that the ventricles not retain any blood at the end of the cardiac cycle." B. "Recall that the heart sounds that we listen to as part of our assessments are the sounds of the myocardium contracting." C. "The diastolic phase is characterized by relaxation of ventricles and their filling with blood." D. "Aortic pressure will exceed ventricular pressure during systole."

Ans: C Diastole is associated with ventricular filling and relaxation. Cardiac output is not 100% (or near to it) with each cardiac cycle, and heart sounds are associated with valve closing. Ventricular pressure exceeds that of the aorta during systole.

2. In which situation would blood MOST likely be rapidly relocated from central circulation to the lower extremities? A. A client undergoes a stress test on a treadmill. B. A client does isotonic exercises in a wheelchair C. A client is helped out of bed and stands up D. A client reclines from a sitting to supine position.

Ans: C 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/orthostatic hypotension and reflects the redistribution of blood in the body.

11. In the ICU, the nurse hears an emergency cardiac monitor go off. The nurse looks at the telemetry and notices the client has gone into ventricular tachycardia. The nurse will likely assess for signs/symptoms of: A. development of hypertension with BP 190/98. B. Oxygen deprivation with O2 saturation decreasing to approx.. 90%. C. decreasing cardiac output due to less ventricular filling time. D. Increasing cardiac index by correlating the volume of blood pumped by the heart with an individual's body surface area.

Ans: C One of the dangers of ventricular tachycardia is a reduction in cardiac output because the heart does not have time to fill adequately.

20. A client is in the emergency department is experiencing a massive stroke with extremely low blood flow to the brain exhibited by a BP <60 mm Hg. The nurse suddenly notes there is a sharp rise in the BP to 250 mm Hg. This high BP lasts about 5 minutes and then the BP drops sharply again. The pathophysiologic principle behind this is likely due to the: A. Activation of the autonomic nervous system. B. release of mineralocorticoids. C. CNS ischemic response D. protective homeostatic mechanism.

Ans: C When blood flow to the brain has been sufficiently interrupted to cause ischemia of the vasomotor center, these vasomotor neurons become strongly excited. This causes massive vasoconstriction as a means of raising the blood pressure to levels as high as the heart can pump against. This response is called the CNS ischemic response that can raise BP to levels as high as 270 mmHg for as long as 10 minutes.

5. A physician is teaching a group of medical students about the physiologic basis for damage to the circulatory and neurologic systems that can accompany hypotension. Which response by a student would warrant correction by the physician? A."As vessel wall thickness increases, tension decreases." B. "Smaller blood vessels require more pressure to overcome wall tension." C. "The smaller the vessel radius, the greater the pressure needed to keep it open." D. "Tension and vessel thickness increase proportionately."

Ans: D Tension and vessel wall thickness are inversely proportionate, in that thinner blood vessels have greater tension and vice versa. The other responses all express the correct inverse relationship between tension and wall thickness.

12. A nurse is taking a manual measure of a client's blood pressure. The nurse knows that which factors related to blood flow underlies the ability to hear blood pressure by auscultation? A. the force of blood with each cardiac contraction produces friction on vessel well that can be heard and felt. B. The movement of smooth muscle surrounding vessels produces noise that is audible by stethoscope. C. turbulent flow of blood during systole produces sound while laminar flow during diastole is silent D. pressure pulsation that exceeds the velocity of blood flow is audible and coincides with systolic BP.

Ans: D The pressure pulsations that accompany intermittent blood ejection from the ventricles cause sounds that are audible when measuring blood pressure, and these pulsations are palpable at pulse sites. Friction, muscle movement, and turbulent blood flow do not account for the pressure pulsations.

25. A client with uncontrolled hypertension has reviewed the echocardiogram report prior to visiting the health care provider. The client asks, "What does it mean when my ejection fraction is measured as only 30%? I want to know how to get this back to normal." Which response by the provider is most accurate? A. "Most likely, your low ejection fraction is caused by your uncontrolled high blood pressure." B. "With the right combination of heart medication and diuretics, your ejection fraction should return back to normal." C. "This low ejection fraction means you have heart failure and need to go on more medication." D. "If you are feeling fine without any chest pain, there should be no need to prescribe any further medications."

Ans; A The left ventricular ejection fraction (normally about 55% to 75% when determined by echocardiography) is frequently used to evaluate the prognosis of clients with a variety of heart disease. Long-standing hypertension can be a cause of low ejection fraction. Medications can help maintain the ejection fraction, but it is unlikely that medications can return the ejection fraction back to the normal range.