Nokea
When caring for a client with dysfunction in the conduction system, at which period would the nurse note that cells are resistant to stimulation?
- A. During polarization
- B. During depolarization
- C. During repolarization
- D. During the refractory period
Correct Answer: D
Rationale: The refractory period is the time when cells are resistant to electrical stimulation. Repolarization is when the ions realign themselves to wait for an electrical signal. Depolarization occurs during muscle contraction when positive ions move inside the myocardial cell membrane and negative ions move outside. Before an impulse is generated, the cells are in a polarized state.
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The nurse is reviewing lab work for a client whose blood CO2 level is elevated. The nurse is most correct to suspect an impairment of which?
- A. Alveoli
- B. Bronchi
- C. The pulmonary artery
- D. The pulmonary vein
Correct Answer: A
Rationale: Gas exchange occurs in the lung where oxygen in inspired air exchanges for CO2 in the venous blood. The CO2 is then transferred to the alveoli to be exhaled. No gas exchange occurs in the bronchi. The pulmonary artery carries deoxygenated blood to the lungs, and the pulmonary vein brings oxygenated blood back to the heart to be pumped to the tissues.
The nurse is caring for an elderly client with left-sided heart failure. When auscultating lung sounds, which adventitious sound is expected?
- A. Whistling
- B. Rhonchi
- C. Crackles
- D. Coarseness
Correct Answer: C
Rationale: When the left side of the heart is pumping inefficiently, blood backs up into the pulmonary veins and lung tissue. Auscultation reveals a crackling sound. Wheezes and gurgles may also be heard.
The nurse is caring for a client with an elevated blood pressure and no previous history of hypertension. At 0900, the blood pressure was 158/90 mm Hg. At 0930, the blood pressure is 142/82 mm Hg. The nurse is most correct when relating the fall in blood pressure to which structure?
- A. Chemoreceptors
- B. Sympathetic nerve fibers
- C. Baroreceptors
- D. Vagus nerve
Correct Answer: C
Rationale: Baroreceptors sense pressure in nerve endings in the walls of the atria and major blood vessels. The baroreceptors respond accordingly to raise or lower the pressure. Chemoreceptors are sensitive to pH, CO2, and O2 in the blood. Sympathetic nerve fibers increase the heart rate. The vagus nerve slows the heart rate.
In which client does the nurse consider the presence of an S3 heart sound to be normal?
- A. In a client who is in elementary school
- B. In a client who is an older adult
- C. In a client with an indwelling pacemaker
- D. In a client who is diagnosed with heart failure
Correct Answer: A
Rationale: A heart sound that follows S1 and S2 is called an S3 heart sound, or a ventricular gallop. Although an abnormal finding for many clients, this finding is considered normal in many pediatric clients, including a school-age client. In adults, the presence of S3 may signify heart failure, so this is not considered normal. Additionally, S3 is not considered normal for older adult clients nor for a client who has an indwelling pacemaker.
The nurse caring for a client who is suspected of having cardiovascular disease has a stress test ordered. The client has a comorbidity of multiple sclerosis, so the nurse knows the stress test will be drug induced. What drug will be used to dilate the coronary arteries?
- A. Thallium
- B. Lorazepam
- C. Diazepam
- D. Dobutamine
Correct Answer: D
Rationale: Drugs such as adenosine (Adenocard), dipyridamole (Persantine), or dobutamine (Dobutrex) may be administered singularly or in combination by the IV route. The drugs dilate the coronary arteries, similar to the vasodilation that occurs when a person exercises to increase the heart muscle's blood supply. The other drugs would not dilate the coronary arteries.