Which of the following best describes the function of the sarcoplasmic reticulum in skeletal muscle fibers?

Question

BlackTom AI · Accepted Answer

First, let’s restate the question and the options so we have a clear reference point for each choice.
Question: Which of the following best describes the function of the sarcoplasmic reticulum in skeletal muscle fibers?
Answer options:
- Conducts action potentials
- Stores and releases calcium ions
- Contains motor end plates
- Synthesizes ATP

Now, evaluating each option in turn:
Option 1: Conducts action potentials. In skeletal muscle, the conduction of action potentials is primarily the role of the sarcolemma (the muscle cell membrane) and the transverse tubules (T-tubules) that propagate electrical signals inward. The sarcoplasmic reticulum (SR) is not responsible for carrying the action potential itself, so this statement is inaccurate as a description of SR function.

Option 2: Stores and releases calcium ions. This is a central feature of the SR. The SR membranes pump calcium ions into storage using calcium-ATPases, and when a muscle cell is stimulated, they release Ca2+ into the cytosol to trigger actin-myosin interactions and contraction. This explanation aligns with the SR’s well-established role in calcium handling and excitation-contraction coupling, making this option the best description of SR function.

Option 3: Contains motor end plates. Motor end plates are specialized regions of the muscle cell membrane where the nerve impulse from a motor neuron is transmitted across the neuromuscular junction. These structures are located on the sarcolemma, not in the sarcoplasmic reticulum, so this statement misattributes a location to motor end plates.

Option 4: Synthesizes ATP. While ATP is essential for muscle contraction and is produced mainly by mitochondria (via cellular respiration) and to some extent glycolysis in the cytoplasm, the sarcoplasmic reticulum itself does not synthesize ATP. Therefore, this option does not describe SR function accurately.

In summary, option 2 correctly identifies the sarcoplasmic reticulum’s primary function as storing and releasing calcium ions, which is critical for initiating muscle contraction. The other options describe roles tied to other cellular components or processes (sarcolemma/T-tubules for action potentials, motor end plates at the NMJ, and ATP synthesis by mitochondria), which are not functions of the SR.

PHYSIO 3200 AU2025 (33564) Quiz # 5 Dr. Heissler's content

Which of the following best describes the function of the sarcoplasmic reticulum in skeletal muscle fibers?

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PHYSIO 3200 AU2025 (33564) Quiz # 5 Dr. Heissler's content

Which of the following best describes the function of the sarcoplasmic reticulum in skeletal muscle fibers?

查看解析

登录即可查看完整答案

类似问题

Antagonists muscle group: A to B: EJ __extenders __ B to A: EJ __ extenders __ Antagonists are passively __ lengthening __ from A to B and passively __shortening __ from B to A.

Question1.20 Which of the following does NOT directly impact force production potential of a muscle? Muscle volume Muscle fibre type Neural recruitment frequency Muscle fibre Pinnation Muscle length ResetMaximum marks: 1 Flag question undefined

Stretching exercises are designed to lengthen the muscle tissue and help it relax to its normal resting state.

What molecular event terminates muscle contraction in skeletal muscle?

Question at position 38 Why is the regulation of calcium in the sarcoplasm important for muscle function?To enhance the muscle's ability to relaxTo increase the availability of oxygen to the muscle fibersTo prevent muscle contraction from becoming too slowTo avoid abnormal muscle contraction

Muscle tissue has all of the following properties except ________.

Question at position 65 Skeletal muscle is considered voluntary because it cannot perform actions subconsciously.TrueFalse

Question at position 55 Which property of muscle tissue enables it to respond to a stimulus, such as a hormone or motor neuron signal?ContractilityElasticityExcitabilityExtensibility

更多留学生实用工具

希望你的学习变得更简单

Antagonists muscle group: A to B: EJ extenders B to A: EJ extenders Antagonists are passively lengthening from A to B and passively shortening from B to A.