ATI RN
Questions About Muscular System with Answers Questions
Question 1 of 5
Muscles that work opposite one another are called
Correct Answer: A
Rationale: Antagonists are muscles with opposing actions, like biceps flexing the elbow and triceps extending it, ensuring balanced movement and control. Agonists (prime movers) drive the main action, contracting together. Synergists assist agonists, stabilizing or refining motion. Prime movers overlap with agonists, not opposites. Antagonists' counteraction is unique, relaxing when agonists contract, distinct from cooperative or leading roles, essential for coordinated, reversible motion in the musculoskeletal system.
Question 2 of 5
Identify the function of the muscles on the medial region of the thigh.
Correct Answer: B
Rationale: Medial thigh muscles, like adductor longus, pull the thigh toward the midline, adducting it, as in crossing legs. Abduction moves it outward, a lateral thigh role. Leg extension (knee) or flexion involves quadriceps or hamstrings, not medial focus. Adduction defines their action, distinct from lateral, knee, or bending functions, key for thigh stability.
Question 3 of 5
Which of the following will NOT be triggered by the release of acetyl choline in the synapse at the neuromuscular junction during muscle contraction?
Correct Answer: C
Rationale: At the neuromuscular junction, acetylcholine release initiates muscle contraction by binding to receptors on the muscle membrane, causing depolarization and an action potential that propagates along the fiber. This triggers calcium release from the sarcoplasmic reticulum, which binds to troponin, shifting tropomyosin to expose myosin-binding sites on actin, enabling contraction. These events form a direct cascade from acetylcholine's action. However, ATP binding to the myosin head occurs later in the cross-bridge cycle, detaching myosin from actin after a power stroke, a process not directly initiated by acetylcholine but part of the contraction-relaxation cycle powered by ATP hydrolysis. This distinction highlights that while calcium and actin exposure are immediate downstream effects, ATP's role is a subsequent step, reliant on energy dynamics rather than the initial synaptic signal, making it the exception in this sequence.
Question 4 of 5
Which of the following is NOT a shoulder muscle?
Correct Answer: D
Rationale: Shoulder muscles, like deltoid, supraspinatus, and teres minor, act on the shoulder joint. Deltoid abducts the arm, supraspinatus initiates abduction, and teres minor rotates it, all part of the rotator cuff or girdle musculature. Pectineus, in the thigh, flexes and adducts the hip, not the shoulder it's a medial thigh muscle. Subscapularis, another rotator cuff muscle, was replaced here to fit four options, but pectineus remains the outlier. Its hip-focused action contrasts with shoulder-specific roles, distinguishing it as unrelated to shoulder movement or stability in the musculoskeletal system.
Question 5 of 5
What endogenous substrate source provides the most energy during moderate to high intensity exercise?
Correct Answer: B
Rationale: Muscle glycogen provides the most energy during moderate to high-intensity exercise, like running or cycling, via glycolysis, rapidly yielding ATP anaerobically or aerobically. Stored in muscle (300-500g), it's directly accessible, powering sustained efforts as intensity limits fat oxidation. Liver glycogen (100g) supports blood glucose but depletes fast, less impactful locally. Intramuscular lipids contribute at lower intensities, insufficient for high demand. Adipose tissue lipids, vast but slow to mobilize, dominate in prolonged low-intensity states, not moderate-high. Muscle glycogen's quantity and rapid breakdown distinguish it, critical for intense performance, unlike smaller or slower sources.