NEET Biology: Disorders of muscular and skeletal system-Tetany Practice Questions
13 free multiple-choice questions on Disorders of muscular and skeletal system-Tetany (Locomotion and Movement) for NEET Biology, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. Which component of the muscle cell membrane is directly responsible for propagating the electrical impulse that leads to uncontrolled contraction during tetany?
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Correct answer: B — Voltage-gated Sodium Channels
The propagation of the action potential along the sarcolemma is governed by the opening and closing of voltage-gated ion channels, especially sodium channels, which dictate muscle excitability.
Q2. Which cellular process is fundamentally disrupted in tetany disorders due to improper neuromuscular signaling?
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Correct answer: A — Muscle fiber excitation-contraction coupling
Tetany results from a failure in the proper excitation-contraction coupling mechanism, where the nerve signal cannot translate into appropriate muscle contraction, leading to sustained spasm.
Q3. Which ion plays the most critical role in triggering the release of calcium from the sarcoplasmic reticulum, initiating muscle contraction?
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Correct answer: B — Calcium
Calcium ions (Ca²⁺) are the key signaling ions that bind to regulatory proteins, leading to the release of Ca²⁺ from the sarcoplasmic reticulum, which triggers the sliding filament mechanism and muscle contraction.
Q4. The involuntary spasms characteristic of tetany are caused by an imbalance in the excitation-contraction coupling mechanism primarily at which level?
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Correct answer: A — Muscle Fiber Membrane
The uncontrolled muscle spasms occur due to improper excitation-contraction coupling, which is governed by the interaction between the nerve signal and the muscle fiber membrane (sarcolemma).
Q5. Which structural element within the muscle fiber is directly responsible for the physical manifestation of the involuntary muscle contractions seen in tetany?
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Correct answer: C — Muscle fibers
The physical contraction (spasm) occurs when the contractile proteins (actin and myosin) within the sarcomeres are over-activated.
Q6. Hypocalcemia (low blood calcium) directly impacts the excitability of nerves and muscles, leading to what type of disorder?
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Correct answer: B — Tetany
Low levels of calcium in the blood cause increased excitability of the nerve and muscle membranes, which manifests as tetany.
Q7. The disruption of the proper signaling pathway at the neuromuscular junction, often involving altered ion flow, can lead to muscle spasms. Which mechanism is most directly affected by the ionic balance at this junction?
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Correct answer: C — Release of Ca²⁺ into the sarcoplasm
The transmission of the nerve impulse to the muscle fiber requires proper Ca²⁺ release from the sarcoplasmic reticulum. Imbalances in the surrounding ion environment directly impact the efficiency and timing of this critical release mechanism.
Q8. Which component is directly responsible for transmitting the electrical signal from the nerve to the muscle cell?
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Correct answer: C — Synapse
The synapse is the junction where the electrical signal from the nerve is converted and transmitted to the muscle cell, leading to excitation.
Q9. The excessive muscle tone and stiffness associated with tetany reflect a failure in the normal regulatory process of muscle relaxation, involving which cellular process?
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Correct answer: D — Ion channel regulation
Muscle relaxation depends on the proper regulation of ion channels, particularly calcium handling, which is disrupted during tetany.
Q10. Tetany is characterized by uncontrolled muscle spasms primarily due to:
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Correct answer: D — Altered membrane excitability
The spasms arise from an imbalance in the membrane excitability of muscle fibers, making them hypersensitive to stimuli and prone to involuntary contraction.
Q11. Tetany is characterized by sustained, involuntary muscle contraction. This condition is often linked to disturbances in the balance of which two major extracellular ions that regulate muscle tone?
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Correct answer: D — Na⁺ and Ca²⁺
Muscle excitability and relaxation are finely tuned by the concentrations of extracellular K⁺ and Mg²⁺. Imbalances in these ions directly interfere with the excitation-contraction coupling process, causing sustained contraction (tetany).
Q12. Improper regulation of which factor contributes significantly to the over-excitability seen in muscle disorders like tetany?
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Correct answer: B — Extracellular Calcium flux
The flux and regulation of calcium ions in the extracellular space play a critical role in setting the threshold for muscle excitability.
Q13. Which ion is primarily responsible for maintaining the resting membrane potential in excitable cells, and its imbalance significantly affects neuromuscular function?
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Correct answer: D — K⁺
The resting membrane potential is largely established by the Na⁺/K⁺ pump, and the concentration gradient of K⁺ is crucial for setting the resting potential and initiating the repolarization phase of the action potential.
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