ATI RN
Questions About Muscular System with Answers Questions
Question 1 of 5
What are the spaces between neurons?
Correct Answer: A
Rationale: Neurons communicate across small gaps where signals are transmitted chemically or electrically. These spaces, called synapses, lie between a neuron's axon terminal and another's dendrites or cell body, facilitating neurotransmitter release and signal propagation. Dendrites receive signals but aren't the gap. Interneurons connect neurons, not define spaces. Ganglia are neuron clusters, not gaps. Synapses' role as the critical junction for neural communication, enabling brain function and reflexes, distinguishes them, reflecting their structural and functional significance in the nervous system.
Question 2 of 5
Equal armed balance is balanced when 20 washers are on one side, and 10 bolts are on the other. Four bolts are added to one side. How many washers must be added to the next side to maintain balance?
Correct Answer: B
Rationale: An equal-armed balance requires equal torque (weight × distance) on both sides. Initially, 20 washers balance 10 bolts, so one bolt equals two washers in weight (20/10 = 2). Adding four bolts increases that side's weight by four bolts, equivalent to 4 × 2 = 8 washers. To maintain balance, eight washers must be added to the other side, keeping total 'washer-equivalents' equal (20 + 8 = 28 vs. 10 × 2 + 4 × 2 = 28). Other options misalign this ratio, making eight the precise counterbalance.
Question 3 of 5
Once myosin binds to actin, heads change shape and slide the This is the sliding filament theory.
Correct Answer: D
Rationale: Myosin heads bind actin, change shape via ATP hydrolysis, and slide actin toward the sarcomere's center, the core of sliding filament theory, shortening the muscle. Actin doesn't slide myosin it's pulled. Troponin regulates, not slides, myosin or actin it shifts tropomyosin. Myosin sliding actin defines the power stroke, distinguishing it from regulatory or reversed actions, essential for contraction mechanics.
Question 4 of 5
During muscle cell contraction, what happens because of $\mathrm{Ca}^{++}$binding to troponin?
Correct Answer: A
Rationale: Calcium drives contraction by binding troponin, a thin filament protein. This binding alters troponin's shape, shifting tropomyosin away from actin's myosin-binding sites, exposing them for cross-bridge formation. Acetylcholine triggers the initial nerve signal, not calcium's role. Cross-bridge disengagement follows ATP binding, not calcium's action, and ATP hydrolysis energizes myosin beforehand. Calcium's specific effect on troponin unveils actin sites, enabling the sliding filament mechanism, a pivotal step distinguishing it from nerve initiation or energy cycles in muscle physiology.
Question 5 of 5
Where are the semimembranosus and semitendinosus muscles located? In the:
Correct Answer: B
Rationale: Semimembranosus and semitendinosus, with biceps femoris, form the hamstrings on the posterior thigh, aiding knee flexion and hip extension. The seminal vesicle is a reproductive organ, the forearm contains arm flexors/extensors, and back muscles (e.g., latissimus dorsi) differ in function and location. The thigh's dorsal placement aligns with hamstring anatomy, distinguishing it from unrelated regions, key for understanding lower limb movement.