ATI RN
Questions About the Muscular System Questions
Question 1 of 5
Which statement best reflects slow, oxidative skeletal-muscle fibers?
Correct Answer: A
Rationale: Slow, oxidative skeletal muscle fibers (Type I) excel in endurance, resisting fatigue due to high mitochondrial density and oxidative enzyme activity, relying on aerobic metabolism. Their red color stems from abundant myoglobin, an oxygen-storing protein, and rich capillary networks, supporting sustained activity like posture maintenance or marathon running. Fast fibers (Type II), white or pale, depend on glycolysis, fatiguing quickly in bursts like sprinting. Pink fibers, an intermediate type (Type IIa), blend traits but aren't slow or maximally enduring. Histochemical staining reveals Type I's oxidative capacity up to 50% more mitochondria than fast fibers and their myoglobin content, absorbing red light. White fibers, low in myoglobin, fatigue rapidly under anaerobic conditions. Red fast fibers exist but prioritize speed over endurance. Exercise science links these traits to function: slow fibers' fatigue resistance suits long-term effort, contrasting with fast fibers' power, making their slow, red profile distinct in muscle classification.
Question 2 of 5
When a 90-year-old patient says, My old bones are just about done in, the nurse reminds him that his bones are being constantly renewed through the action of:
Correct Answer: A
Rationale: Bone renewal is an ongoing process called remodeling, driven by osteoblasts, cells that build new bone by depositing mineralized matrix. This counters the patient's notion of bones wearing out, as osteoblasts work with osteoclasts (which break down bone) to maintain skeletal health, even in old age. Stem cells contribute broadly to tissue repair but aren't specific to bone renewal. Free calcium ions are raw materials, not active agents. Phosphorus and vitamin D support mineralization, but osteoblasts execute the process. Highlighting osteoblasts reassures the patient that regeneration persists, emphasizing the dynamic nature of bone tissue over passive nutrient roles.
Question 3 of 5
A patient with osteoporosis calls the nurse in the doctor s office to report that she has forgotten to take her weekly bisphosphonate (alendronate [Fosamax]) for 2 days past the weekly time. The nurse should advise the patient to:
Correct Answer: C
Rationale: Bisphosphonates like alendronate are taken weekly to slow bone loss in osteoporosis, with strict timing to maximize absorption and minimize side effects. Missing it by 2 days means taking it late could overlap with the next dose, risking irritation or reduced efficacy. Taking it now is tempting but disrupts the schedule. Two doses 3 days apart or doubling up now with a snack (which impairs absorption) violate dosing guidelines, potentially causing esophageal harm. Skipping this week and resuming next week maintains the regimen's consistency and safety, as the drug's long-acting nature means one missed dose won't drastically affect treatment, making it the best advice for adherence and health.
Question 4 of 5
The nurse is performing an assessment on the patient who is in bilateral Buck s traction. Which finding indicates the need to reposition the patient?
Correct Answer: A
Rationale: Buck's traction uses weights and pulleys to align a leg fracture, requiring proper positioning to avoid complications. Heels not touching the mattress suggest the legs are elevated or misaligned, risking pressure on the heels or traction ineffectiveness, necessitating repositioning. Rewrapping bandages addresses maintenance, not position. Feet against the footboard could indicate too much pull, but it's less urgent if traction remains functional. Free-hanging weights are correct for traction. Heels off the bed signal a positional flaw, potentially causing skin breakdown or misalignment, making it the priority for adjustment to ensure therapeutic effect.
Question 5 of 5
A muscle that assists the prime mover by reducing undesired action or unnecessary movement.
Correct Answer: A
Rationale: Synergists are muscles that assist the prime mover by stabilizing joints or reducing unwanted movements, enhancing the efficiency of the intended action. For example, when flexing the elbow, synergist muscles stabilize the wrist to focus the biceps' effort. Antagonist' muscles oppose the prime mover, not assist it. Intramuscular (IM) injection is a medical procedure, not a muscle type. The prime mover is the primary muscle responsible for the action, not an assistant. Synergists play a crucial supportive role in refining movement, making them the correct choice, as they align with the description of reducing unnecessary motion while complementing the prime mover's function.