The term used to describe the relaxation of the myocardium to allow ventricles to fill with blood is:
stroke volume.
afterload.
systole.
diastole.
The Correct Answer is D
Choice A rationale
Stroke volume is the amount of blood ejected by the left ventricle in one single contraction. It is the difference between end-diastolic volume and end-systolic volume. While it depends on the filling that occurs during relaxation, it is a measure of output rather than the state of the muscle during the filling phase. Normal stroke volume is approximately 60 to 100 mL per beat. Factors affecting stroke volume include preload, myocardial contractility, and the systemic resistance or afterload.
Choice B rationale
Afterload is the resistance the heart must pump against to eject blood into the systemic circulation. It is primarily determined by the diameter of the arterioles and the pressure in the aorta. Afterload occurs during the systolic phase of the cardiac cycle when the ventricles are contracting, not during the relaxation phase. High afterload increases the workload of the heart and can lead to ventricular hypertrophy over time if the condition remains chronic or is left untreated.
Choice C rationale
Systole is the phase of the cardiac cycle when the heart muscle contracts and pumps blood from the chambers into the arteries. During ventricular systole, the mitral and tricuspid valves close, and the aortic and pulmonary valves open. This is the period of high pressure and active work. Systole is the opposite of relaxation; it is the time of ejection. A normal systolic blood pressure for an adult is generally considered to be less than 120 mmHg.
Choice D rationale
Diastole is the period of the cardiac cycle when the heart muscle relaxes and the chambers fill with blood. During ventricular diastole, the ventricles expand to receive blood from the atria. This relaxation is essential for adequate preload and subsequent cardiac output. Diastole encompasses both the early rapid filling phase and the atrial kick. Normal diastolic pressure is less than 80 mmHg. Proper diastolic function ensures the myocardium receives adequate coronary perfusion, which mostly occurs when the muscle is relaxed.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
Choice A rationale
Stress is considered a modifiable risk factor because individuals can adopt various coping mechanisms and lifestyle changes to reduce its impact on the body. Chronic stress triggers the sympathetic nervous system, leading to sustained elevations in cortisol and adrenaline, which increase blood pressure. Through techniques such as mindfulness, cognitive behavioral therapy, or environmental adjustments, a patient can successfully lower their stress levels and subsequently reduce their risk for hypertension.
Choice B rationale
Obesity is a modifiable risk factor that is directly linked to metabolic and cardiovascular health. Excessive adipose tissue increases systemic vascular resistance and places a higher demand on the heart to pump blood. However, weight can be managed and reduced through a combination of caloric restriction and increased physical energy expenditure. Achieving a healthy Body Mass Index significantly lowers the mechanical and chemical strain on the circulatory system.
Choice C rationale
Gender is a non-modifiable risk factor because it is determined by biological sex chromosomes and the resulting hormonal profile established at birth. Statistical data shows that men often develop hypertension earlier in life compared to premenopausal women, largely due to the protective effects of estrogen. Since an individual cannot change their biological sex or the innate hormonal framework they were born with, it is classified as a permanent risk characteristic.
Choice D rationale
Sodium intake is a modifiable risk factor because it is entirely dependent on an individual's nutritional choices and eating habits. High sodium consumption leads to water retention and increased extracellular fluid volume, which directly raises blood pressure levels. By adhering to a low-sodium diet, such as the DASH diet, patients can effectively decrease the osmotic pressure within their vessels. This behavioral change is a cornerstone of non-pharmacological hypertension management.
Correct Answer is D
Explanation
Choice A rationale
Calcification is the accumulation of calcium salts in body tissues, which can cause the tissue to harden. While calcification can occur within atherosclerotic plaques, making the arteries rigid, it is a broader biological process that can happen in heart valves, kidneys, or soft tissues. It is a secondary component of the narrowing process rather than the term for the narrowing itself caused specifically by plaque. In the context of arteries, it often signifies an advanced stage of vascular disease.
Choice B rationale
Thrombophlebitis is an inflammatory process that causes a blood clot to form and block one or more veins, usually in the legs. While it involves a blockage, it occurs in the venous system rather than the arterial system and is caused by a thrombus rather than the chronic buildup of fatty plaques. Symptoms include redness, swelling, and pain in the affected area. It is a different pathological entity from the chronic arterial narrowing described in the prompt's question.
Choice C rationale
Myocarditis is the inflammation of the heart muscle, known as the myocardium. It is most often caused by viral infections, but can also result from drug reactions or inflammatory conditions. Symptoms include chest pain, fatigue, and shortness of breath. Myocarditis affects the muscle tissue's ability to pump blood and can lead to heart failure or arrhythmias. It does not involve the narrowing of the arteries due to plaque buildup, which is a vascular rather than a primary muscular issue.
Choice D rationale
Atherosclerosis is a specific type of arteriosclerosis characterized by the buildup of fats, cholesterol, and other substances in and on the artery walls. This buildup is called plaque. Over time, these plaques can narrow the lumen of the arteries, restricting blood flow to vital organs. If a plaque ruptures, it can trigger a blood clot. This process is the underlying cause of many cardiovascular diseases, including coronary artery disease and peripheral artery disease. Risk factors include high cholesterol and smoking.
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