A nurse is assessing a client who is 75 years old. Which of the following findings is most likely related to the decreased contractile strength of the myocardium in older adults?
Increased heart rate
Decreased stroke volume
Increased cardiac output.
Decreased peripheral resistance.
The Correct Answer is B
The correct answer is B. Decreased stroke volume.
Stroke volume is the amount of blood pumped by the left ventricle of the heart in one contraction.
The contractile strength of the myocardium determines how much blood is ejected with each beat. As people age, the myocardium becomes less elastic and less responsive to catecholamines, which can reduce the contractile force and lower the stroke volume.
Choice A is wrong because increased heart rate is not related to the decreased contractile strength of the myocardium, but rather to the decreased responsiveness of the baroreceptors, which regulate blood pressure. Older adults may have higher resting heart rates and lower maximum heart rates than younger adults.
Choice C is wrong because increased cardiac output is not related to the decreased contractile strength of the myocardium, but rather to the increased blood volume and cardiac workload that may occur with aging. Cardiac output is the product of stroke volume and heart rate, so a lower stroke volume would tend to decrease cardiac output.
Choice D is wrong because decreased peripheral resistance is not related to the decreased contractile strength of the myocardium, but rather to the decreased elasticity and increased stiffness of the arterial walls that may occur with aging.
Peripheral resistance is the opposition to blood flow caused by friction between the blood and the vessel walls. A higher peripheral resistance would increase the afterload on the heart and reduce the stroke volume.
Normal ranges for stroke volume are 60 to 100 mL/beat for men and 50 to 90 mL/beat for women.
Normal ranges for heart rate are 60 to 100 beats per minute for adults.
Normal ranges for cardiac output are 4 to 8 L/min for adults.
Normal ranges for peripheral resistance are 800 to 1200 dynes/sec/cm- for adults.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
The correct answer is A.“I may notice my hair becoming thinner and grayer as I age.” This statement reflects the common changes in hair that occur with aging, such as reduced melanin production, slower growth rate, and smaller hair strands.
Choice B is wrong because nails do not grow faster and stronger with age, but rather more slowly and may become dull and brittle.
Choice C is wrong because hair does not become more oily and curly with age, but rather drier and finer.
Choice D is wrong because nails do not become smoother and shinier with age, but rather yellowed and opaque.
Normal ranges for hair and nail growth vary depending on factors such as genetics, nutrition, health conditions, and environmental exposure.
However, some general estimates are:.
• Fingernails grow about 3 mm per month and toenails grow about 1 mm per month.
• Hair grows about 0.5 inches per month and loses about 50 to 100 strands per day.
• Hair color changes from about 30% gray at age 50 to about 50% gray at age 70.
Correct Answer is C
Explanation
The correct answer is C.
Decreased liver function.Older adults are at increased risk for adverse drug reactions due to various physiological changes that affect the absorption, distribution, metabolism and excretion of drugs.One of these changes is the reduction in liver blood flow, size, drug-metabolizing enzyme content and function.This can result in slower or decreased metabolism of drugs, leading to higher plasma concentrations and increased risk of toxicity.
Choice A is wrong because older adults have decreased renal clearance, not increased.This means that drugs that are eliminated by the kidneys may accumulate in the body and cause adverse effects.
Choice B is wrong because older adults have decreased plasma protein levels, not increased.This means that drugs that are bound to plasma proteins may have higher free fractions and increased pharmacological effects.
Choice D is wrong because older adults have increased permeability of the blood-brain barrier, not decreased.This means that drugs that cross the blood-brain barrier may have enhanced central nervous system effects in older adults.
Normal ranges for liver function tests vary depending on the laboratory and the method used, but some common values are:.
• Alanine aminotransferase (ALT): 7-55 U/L.
• Aspartate aminotransferase (AST): 8-48 U/L.
• Alkaline phosphatase (ALP): 45-115 U/L.
• Total bilirubin: 0.1-1.2 mg/dL.
• Albumin: 3.5-5 g/dL.
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