ATI RN
Multiple Choice Questions on Muscular System Questions
Question 1 of 5
Which of the following is a muscle whose insertion is found on the clavicle and acromion process of the scapula within the pectoral girdle?
Correct Answer: A
Rationale: The trapezius inserts on the clavicle and acromion process of the scapula, stabilizing and moving the shoulder girdle, such as in shrugging. Pectoralis major inserts on the humerus, not the clavicle or acromion. Latissimus dorsi inserts on the humerus too, affecting the arm. Gracilis is a thigh muscle, unrelated. Trapezius is the correct answer, as its insertion matches the question's sites, playing a key role in pectoral girdle motion and posture, distinct from arm-focused muscles.
Question 2 of 5
Voluntary muscle is a
Correct Answer: A
Rationale: Voluntary muscles, synonymous with skeletal muscles, allow conscious control over actions like lifting an arm or turning the head. Linked to bones via tendons, they respond to brain signals via the somatic nervous system, enabling deliberate movement. No control describes involuntary muscles smooth and cardiac working automatically, like digestion or heartbeats. Automatic function fits those, not voluntary ones. Muscles fused together misrepresents anatomy muscles are distinct, not merged. Voluntary muscle's defining trait is this control, essential for daily tasks, contrasting with involuntary types' autonomic roles, highlighting its role in purposeful, cognitive-directed motion across limbs, neck, and torso.
Question 3 of 5
This is a major energy source in a hurdle race to the leg muscles
Correct Answer: D
Rationale: In a hurdle race, a high-intensity, endurance-based activity lasting over a minute, leg muscles primarily rely on oxidative metabolism for energy. This process uses oxygen to break down glucose, fats, and proteins in mitochondria, producing ATP efficiently via the aerobic pathway, sustaining prolonged effort. Glycolysis provides quick ATP anaerobically but fatigues muscles due to lactate buildup, insufficient for a race's duration. Lactate and pyruvate are intermediates, not primary sources. Preformed ATP is limited, depleting in seconds. Oxidative metabolism dominates in events requiring sustained power, like hurdling, where oxygen delivery supports muscle contraction over time, distinguishing it from short-burst energy systems and aligning with the aerobic demands of such races.
Question 4 of 5
The thin filaments of a sarcomere are made up of
Correct Answer: D
Rationale: Thin filaments in a sarcomere consist of actin, troponin, and tropomyosin, forming a complex that interacts with myosin for contraction. Actin provides the structural backbone, tropomyosin covers binding sites in rest, and troponin binds calcium to shift tropomyosin, exposing sites for myosin. Only actin oversimplifies, ignoring regulatory proteins. Only myosin misplaces it myosin forms thick filaments. Actin and myosin together suggest a mix, but they're separate filaments. The trio of actin, troponin, and tropomyosin defines thin filaments, enabling controlled contraction, distinct from incomplete or incorrect combinations, critical for the sliding filament theory and muscle movement precision.
Question 5 of 5
The latent period, the contraction period, and the relaxation period are the three stages of a:
Correct Answer: A
Rationale: A muscle twitch, a single contraction-relaxation cycle from one stimulus, has three phases: latent (signal delay to contraction start), contraction (cross-bridge activity shortens muscle), and relaxation (calcium removal, filament separation). A myogram records this, not the event itself. Summation is multiple twitches overlapping, not a single cycle. A motor unit is a neuron and fibers, not a phase sequence. The twitch's distinct stages define its mechanics, distinguishing it from recordings, cumulative effects, or anatomical units, fundamental to muscle response analysis.