Asked by Chantal Shanty on Jul 14, 2024
Verified
Which of the following events occurs during the lag phase of a muscle twitch?
A) Muscle fibers shorten.
B) Cross-bridges form, move, release, and reform many times.
C) The action potential is propagated from presynaptic to postsynaptic membrane.
D) Ca2+ are pumped back into the sarcoplasmic reticulum.
E) All of these events occur in the lag phase.
Lag Phase
One of the three phases of muscle contraction; time between the application of the stimulus and the beginning of muscular contraction; also called latent phase.
Muscle Twitch
Contraction of a whole muscle in response to a stimulus that causes an action potential in one or more muscle fibers.
Sarcoplasmic Reticulum
The Sarcoplasmic Reticulum is an organelle in muscle cells storing calcium ions, essential for muscle contraction and relaxation.
- Recognize the biochemical processes that lead to muscle contraction.
Verified Answer
AV
Angie VargasJul 14, 2024
Final Answer :
C
Explanation :
During the lag phase of a muscle twitch, the action potential is propagated from the presynaptic to the postsynaptic membrane. This phase is the initial period after stimulus before contraction begins, and it involves the transmission of the nerve impulse to the muscle fiber, leading to muscle contraction in subsequent phases.
Learning Objectives
- Recognize the biochemical processes that lead to muscle contraction.