Histology: Muscular Tissue

Which of the following scenarios best illustrates the property of extensibility in muscle tissue?

A researcher is investigating the effect of a new drug on skeletal muscle contraction. They observe that the drug significantly reduces the force of contraction, despite normal nerve stimulation and calcium release. Which of the following is the most likely mechanism of action of this drug?

In a muscle biopsy, a pathologist observes a large number of muscle fibers with high myoglobin content, numerous mitochondria, and a rich capillary supply. These fibers also show a high resistance to fatigue. Which type of muscle fiber is most likely predominant in this sample?

A scientist is studying the effects of a novel compound on muscle tissue. They find that the compound increases the excitability of muscle fibers. Which of the following mechanisms could explain this effect?

A patient has a genetic mutation that affects the function of titin within muscle sarcomeres. Which of the following is the most likely consequence of this mutation?

Which of the following correctly orders the components of a skeletal muscle, from largest to smallest?

A researcher is studying the effects of different exercise regimens on muscle fiber composition. They observe that long-distance runners have a higher proportion of Type I fibers compared to sprinters, who have a higher proportion of Type IIb fibers. What accounts for this difference?

A muscle biopsy from an athlete reveals a predominance of muscle fibers with a high capacity for both oxidative and glycolytic metabolism. These fibers exhibit moderate resistance to fatigue and generate relatively high force. Which muscle fiber type is most abundant in this athlete's muscles?

A toxin inhibits the function of acetylcholinesterase at the neuromuscular junction. What immediate effect would this have on muscle contraction?

A researcher discovers a new drug that selectively targets and disrupts the function of M-line proteins within the sarcomere, potentially impacting muscle function. What is the most likely primary effect of this drug?

A patient is diagnosed with a condition that impairs the function of satellite cells in their skeletal muscles. What is the expected consequence of this impairment?

In a laboratory experiment, a muscle fiber is treated with a drug that selectively blocks dihydropyridine receptors (DHPRs) in the T-tubules. What is the expected outcome of this treatment?

A patient experiences a spinal cord injury that results in the denervation of a group of skeletal muscle fibers. Over time, these denervated muscle fibers begin to atrophy. Which cellular mechanism is most directly responsible for this atrophy?

During intense, anaerobic exercise, such as sprinting, muscle cells rely heavily on glycolysis for ATP production. Which of the following is the most likely consequence of this metabolic pathway?

A researcher is studying muscle contraction in a genetically modified mouse model. They discover that the mice have a mutation that impairs the function of troponin. Which aspect of muscle contraction would be most directly affected by this mutation?

A researcher is investigating the role of different connective tissue layers in skeletal muscle function. What would be the most likely consequence of damaging the epimysium?

When comparing skeletal muscle to smooth muscle, which of the following characteristics is unique to skeletal muscle?

A pharmacologist develops a drug that selectively inhibits the function of ryanodine receptors (RyRs) in skeletal muscle cells. What is the expected effect of this drug on muscle contraction?

Which of the following best describes the role of ATP in skeletal muscle contraction?

A patient presents with muscle weakness and fatigue. A muscle biopsy reveals disorganized sarcomeres and a lack of structural integrity within the muscle fibers. Which protein is most likely deficient or dysfunctional in this patient?

A researcher is investigating the effects of a new drug on skeletal muscle. They find that the drug significantly reduces the velocity of muscle contraction without affecting the maximum force generated. Which of the following is the most likely mechanism of this drug?

What is the functional significance of the extensive network of T-tubules present in skeletal muscle fibers?

A researcher is studying the role of different muscle fiber types in endurance performance. Which metabolic adaptation would be most beneficial for enhancing endurance capacity in skeletal muscle?

A patient with a neuromuscular disorder exhibits muscle weakness and difficulty initiating voluntary movements. They have normal levels of acetylcholine. Further testing reveals a reduced number of functional acetylcholine receptors at the motor end plate. What is the most likely underlying mechanism of this condition?

A scientist is studying the regulation of muscle contraction and discovers a novel protein that binds to tropomyosin. Which of the following effects would this novel protein most likely have on muscle contraction?

What structural feature of skeletal muscle allows for the coordinated and rapid transmission of action potentials to the sarcoplasmic reticulum, ensuring uniform contraction throughout the muscle fiber?

A researcher investigates the structural characteristics of skeletal muscle fibers. They observe an abundance of very thin reticular fibers surrounding individual muscle fibers. Which specific connective tissue component are they observing?

A patient has a condition that impairs the release of calcium ions from the sarcoplasmic reticulum in their skeletal muscle cells. How would this impairment most directly affect the process of muscle contraction?

A muscle fiber is stretched beyond its optimal length. How does this stretching primarily affect the force-generating capacity of the muscle fiber during contraction?

Which of the following mechanisms contributes to muscle fatigue during prolonged, high-intensity exercise?

Following a muscle injury, such as a strain, the process of muscle regeneration is initiated. What substance plays a crucial role in orchestrating the proliferation and differentiation of muscle progenitor cells during this process?

A genetic mutation leads to the production of a non-functional form of nebulin in skeletal muscle. What affect would this have on muscle contraction?

The drug dantrolene is known to treat muscle spasticity by reducing calcium release from the sarcoplasmic reticulum. How does this mechanism of action alleviate muscle spasticity?

Which statement accurately describes the role and position of the Z-line in the structure of a sarcomere?

In fully contracted smooth muscle, what prevents the thin filaments from sliding backward, ensuring sustained contraction?

A researcher is investigating a new neuromuscular disease characterized by impaired muscle contraction. They observe that the affected muscle fibers have a significantly reduced number of T-tubules. What is the most likely consequence of this reduction in T-tubule density?

A researcher is studying the effects of a genetic mutation on skeletal muscle structure. They discover that the mutated gene produces a non-functional version of titin. Which of the following is the most likely consequence of this mutation at the sarcomere level?

A previously unidentified toxin is found to cause rapid muscle fatigue and cramping. Further analysis reveals that the toxin inhibits the function of the sarcoplasmic reticulum Ca2+-ATPase (SERCA) pump. How would this toxin primarily affect muscle function?

A research team discovers a novel compound that selectively targets and disrupts the function of nebulin within skeletal muscle fibers. What aspect of muscle contraction would be most directly affected by this compound?

A novel drug is developed that selectively enhances the activity of acetylcholinesterase at the neuromuscular junction. How would this drug affect skeletal muscle contraction?

A patient is diagnosed with a rare genetic disorder that affects the function of dystrophin. What is the most likely consequence of dysfunctional dystrophin in skeletal muscle?

A researcher is studying the effects of a new drug on skeletal muscle contraction. They observe that the drug significantly reduces the velocity of muscle contraction without affecting the maximum force generated. Which of the following is the most likely mechanism of this drug

Following a severe crush injury to the leg, a patient experiences significant muscle damage. Which cellular mechanism is most crucial for the regeneration of skeletal muscle tissue in this scenario?

In smooth muscle contraction, what is the primary role of calmodulin?

A researcher is investigating the role of different muscle fiber types in endurance performance. Which statement best describes the key adaptations required for enhancing endurance capacity in skeletal muscle?