A student nurse is reviewing for an upcoming examination and recognizes in the ECG readings that the QRS wave represents which of the following?
Atrial depolarization.
Ventricular repolarization.
Atrial repolarization.
Ventricular depolarization.
The Correct Answer is D
Choice A rationale
Atrial depolarization is represented by the P wave on an ECG, not the QRS wave. This phase involves the electrical activation and contraction of the atria, which precedes ventricular contraction.
Choice B rationale
Ventricular repolarization is represented by the T wave, not the QRS complex. The T wave signifies the ventricles returning to their resting state.
Choice C rationale
Atrial repolarization generally occurs during the QRS complex, but it is not represented by it. The electrical activity of atrial repolarization is masked by the more significant ventricular depolarization signal of the QRS complex.
Choice D rationale
The QRS complex on an ECG represents ventricular depolarization, which is the electrical activation leading to the contraction of the ventricles. This is the correct answer as it accurately describes the QRS wave’s significance. .
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Choice A rationale
Separation of the retina from the choroid, also known as retinal detachment, is a different condition altogether. Retinal detachment can cause vision loss but is not related to macular degeneration. This condition often requires immediate medical attention to prevent permanent vision loss and is typically characterized by the sudden appearance of floaters, flashes of light, and a shadow or curtain over a portion of the visual field.
Choice B rationale
Peripheral vision loss and seeing halos around light are more commonly associated with conditions like glaucoma. Glaucoma involves increased intraocular pressure, which can damage the optic nerve and lead to peripheral vision loss and seeing halos around lights. This condition can be managed with medications or surgery to lower intraocular pressure and prevent further vision loss.
Choice C rationale
Complaints of severe pain and pressure in the eye are indicative of acute angle-closure glaucoma. This is a medical emergency and requires prompt treatment to reduce intraocular pressure and prevent optic nerve damage. The symptoms of acute angle-closure glaucoma are sudden and severe and can include headache, nausea, and vomiting, along with the eye pain and pressure.
Choice D rationale
Central vision loss with intact peripheral vision is characteristic of macular degeneration, particularly age-related macular degeneration (AMD). AMD affects the macula, the part of the retina responsible for sharp, central vision. As the macula deteriorates, central vision becomes blurry or wavy, making it difficult to read, drive, or recognize faces, while peripheral vision remains largely unaffected.
Correct Answer is D
Explanation
Choice A rationale
The abducens cranial nerve (CN VI) controls the lateral rectus muscle of the eye, which is responsible for outward movement. It is not assessed using the Snellen visual acuity chart. The function of this nerve is tested through the evaluation of lateral eye movements.
Choice B rationale
The optic cranial nerve (CN II) is responsible for vision, including visual acuity and visual fields. It is assessed using the Snellen visual acuity chart to determine how well a person can see at various distances. This test evaluates the clarity and sharpness of vision, making CN II the correct answer.
Choice C rationale
The trochlear cranial nerve (CN IV) controls the superior oblique muscle, which helps with downward and inward eye movements. It is not assessed using the Snellen visual acuity chart but rather through the evaluation of eye movements and alignment.
Choice D rationale
The oculomotor cranial nerve (CN III) controls most of the eye's movements, including those of the superior, inferior, and medial rectus muscles, as well as the inferior oblique muscle. It is also responsible for controlling the pupil's response to light. The Snellen visual acuity chart does not assess the function of CN III, as it focuses on visual clarity and acuity.
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