ATI RN
Questions About Muscular System with Answers Questions
Question 1 of 5
Which muscle pair plays a role in respiration?
Correct Answer: D
Rationale: Diaphragm and scalenes aid respiration. The diaphragm contracts, expanding the chest for inhalation, while scalenes elevate upper ribs, assisting inspiration. Intertransversarii and interspinales stabilize vertebrae, not breathing. Semispinalis muscles extend the spine, not respiratory. Trapezius and rhomboids move the scapula, unrelated to lungs. Diaphragm-scalene synergy drives breathing, distinguishing them, key for respiratory mechanics.
Question 2 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 3 of 5
In the classification of two organisms, which of the following is the best evidence of a close relationship?
Correct Answer: B
Rationale: Close evolutionary relationships are best shown by genetic similarity. Amino acid sequences in proteins, encoded by DNA, reflect shared ancestry highly conserved sequences indicate recent divergence, as with hemoglobin in mammals. Bone structure suggests relation but converges in unrelated species (e.g., bird and bat wings). Reproduction and respiration methods vary widely even among kin. Protein sequences' molecular precision, tied to genetic heritage, outweighs morphological or functional traits, making it the gold standard in phylogenetic analysis.
Question 4 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 5 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.