ATI RN
Muscular System Exam Questions Questions
Question 1 of 5
The A band in a muscle appears and contains
Correct Answer: A
Rationale: The A band, a sarcomere's dark-staining region under a microscope, spans the length of thick myosin filaments, overlapping with thin actin filaments in its outer zones. This overlap causes its anisotropic property, scattering light and appearing dark, unlike the isotropic (I) band's lighter, actin-only composition. Thick filaments anchor at the M line, while thin filaments extend from Z lines, partially interdigitating within the A band during rest. This dual presence distinguishes it from the H zone (thick only) and I band (thin only). The dark appearance stems from dense protein packing, observable in electron micrographs, and remains constant in length during contraction, unlike shrinking I bands. Thin filaments alone wouldn't account for the A band's width or darkness, nor would thick filaments without actin overlap explain its full structure. Muscle physiology texts confirm this composition, critical for cross-bridge formation in contraction, making the A band's dual-filament nature a cornerstone of sarcomere function.
Question 2 of 5
When the patient returns to the unit from having had an arthrogram, which intervention will the nurse perform first?
Correct Answer: B
Rationale: After an arthrogram, where contrast dye is injected into a joint, the priority is managing potential swelling or discomfort from the procedure. Applying ice packs reduces inflammation and numbs mild pain, addressing immediate post-procedure effects. Ambulating the patient might worsen swelling or discomfort before it's controlled. Passive range-of-motion exercises could irritate the joint further, especially without first reducing inflammation. Wrapping with an elastic bandage helps with support but doesn't directly address swelling as effectively as ice in the initial stage. Ice is the first step because it tackles the physiological response to the injection, setting the stage for subsequent interventions like compression or movement, ensuring patient comfort and recovery.
Question 3 of 5
The nurse is caring for a patient who has had an arthrocentesis. The nurse has completed discharge instructions. Which statement by the patient indicates the need for further instruction?
Correct Answer: A
Rationale: Arthrocentesis, removing fluid from a joint, aims to relieve pressure and improve mobility. Saying the knee mustn't move for 1-2 weeks suggests misunderstanding, as gentle movement is typically encouraged soon after to prevent stiffness, with rest limited to a day or two unless specified otherwise. Steroids reducing inflammation is accurate, as they're often injected post-procedure. Expecting some pain aligns with recovery, as does wearing a bandage for 2-3 days for support. The prolonged immobility statement requires correction, as it contradicts the goal of restoring function, risking complications like adhesions further teaching ensures the patient balances rest and activity correctly.
Question 4 of 5
The patient, who is a legal secretary, asks the nurse how she can avoid developing carpal tunnel syndrome. The nurse suggests:
Correct Answer: C
Rationale: Carpal tunnel syndrome arises from median nerve compression in the wrist, often from repetitive typing without support. A wrist pad maintains a neutral position, reducing strain on the tunnel during prolonged work, a proactive ergonomic fix. Repetitive flexion exercises could worsen pressure on the nerve, increasing risk. Elastic bandages might restrict movement but don't address posture and could impair circulation. Warm compresses soothe but don't prevent the underlying mechanical stress. The pad targets the root cause poor wrist alignment making it the most effective suggestion for a secretary's daily typing demands.
Question 5 of 5
A muscle that stabilizes the origin of the prime mover so that the prime mover can act more efficiently.
Correct Answer: C
Rationale: Fixators are muscles that stabilize the origin of a prime mover, allowing it to move more effectively by preventing unwanted movement at the point of attachment. This stabilization ensures that the force generated by the prime mover is directed toward the intended action, such as lifting or rotating a limb. For example, in shoulder abduction, fixator muscles stabilize the scapula so the deltoid can efficiently lift the arm. Superficial describes muscle location, not function. Synergists assist the prime mover by reducing unnecessary movement or enhancing its action, but they do not specifically stabilize the origin. Aponeurosis is a structural term for a tendon-like sheet, not a muscle type or function. The role of stabilizing the origin is a distinct characteristic of fixators, making it the correct choice here, as it directly supports the prime mover's efficiency in movement.