ATI RN
Multiple Choice Questions Muscular System Questions
Question 1 of 5
Which of the following is an example of a normal physiologic process that uses a positive feedback loop?
Correct Answer: B
Rationale: Childbirth uses a positive feedback loop: uterine contractions increase oxytocin, intensifying contractions until delivery, amplifying the stimulus. Blood pressure , fluid balance , and temperature use negative feedback to stabilize. Positive feedback's escalating nature in labor, per physiology, makes 'b' correct.
Question 2 of 5
A continuous, sustained contraction that shows no relaxation is called
Correct Answer: A
Rationale: Complete tetanus occurs when rapid, repeated stimuli fuse muscle contractions into a sustained, maximal force with no relaxation phase. High-frequency nerve impulses (e.g., 50-100 Hz in humans) keep calcium levels elevated in the sarcoplasm, preventing actin-myosin cross-bridges from disengaging. A twitch is a single, brief contraction-relaxation cycle from one stimulus, lasting 20-100 ms. Incomplete tetanus, with slightly slower stimuli, shows partial relaxation between peaks. Wave summation adds force as stimuli increase before full relaxation, but retains distinct twitches. Treppe enhances force gradually without fusion. Complete tetanus, observable in lab settings or extreme exertion, maximizes tension up to 4-5 times twitch force reflecting sustained motor unit recruitment. Electromyography distinguishes its smooth plateau from twitch's spike or incomplete tetanus's ripples. Physiologically, it mimics intense efforts like lifting heavy loads, contrasting with transient or stepped responses, highlighting muscle's capacity for prolonged output under continuous stimulation.
Question 3 of 5
The nurse informs the patient that the frequency of range-of-motion (ROM) exercises should be:
Correct Answer: C
Rationale: Range-of-motion exercises need to be frequent enough to maintain joint mobility and prevent stiffness, especially in patients at risk of contractures. Performing them 3 to 4 times a day ensures joints are moved through their full range multiple times, counteracting the effects of immobility without overtaxing the patient. Once a day is insufficient, as stiffness can develop within hours of inactivity. Twice daily (morning and afternoon) improves on that but may still allow periods of prolonged immobility. Four to six times might be ideal for severe cases but could exhaust the patient or staff resources unnecessarily. The 3 to 4 times recommendation balances efficacy and practicality, promoting flexibility and circulation while fitting into a realistic care schedule.
Question 4 of 5
When an 88-year-old patient enters the room for her health assessment, she walks with tiny steps, her shoulders are rounded and hunched, and her arms are crossed in front of her with her hands tucked in her armpits. Which response by the nurse is most appropriate?
Correct Answer: A
Rationale: The patient's posture tiny steps, hunched shoulders, and arms crossed with hands tucked suggests she might be cold, as this is a common way to conserve heat. Asking about coldness directly addresses a likely physical cause, opening a dialogue to assess further. Stomach pain might cause hunching but not typically arm-crossing or tiny steps. Shoe size could affect gait, but the full posture doesn't align with that alone. Asking if she always walks like this assumes a chronic issue without exploring immediate discomfort. The coldness question is most appropriate, as it's empathetic, specific to the observed behavior, and prompts clarification, guiding the nurse to tailor care effectively.
Question 5 of 5
The patient in a long arm cast (from below the shoulder to the wrist, with a 90-degree elbow flexion) complains of a burning sensation over the elbow. The nurse s initial intervention should be:
Correct Answer: A
Rationale: A burning sensation over the elbow in a cast suggests pressure or irritation, possibly from swelling or a tight fit. Elevating the arm on pillows is the initial step, as it reduces swelling by improving venous return, potentially relieving pressure on the elbow without invasive action. Checking support is useful but secondary, as elevation addresses the immediate cause. Notifying the charge nurse assumes a pressure ulcer without assessment, which is premature. Cutting a window is a last resort, requiring medical orders. Elevation is a safe, effective first response, tackling the likely swelling-related discomfort while preserving the cast's integrity for further evaluation.