Asked by Cally Harlin on Jul 26, 2024
Verified
The arrival of an action potential causes the release of ____ by the ____.
A) calcium; myofibrils
B) calcium; sarcoplasmic reticulum
C) sodium; myofibrils
D) sodium; sarcoplasmic reticulum
E) actin; myosin heads
Sarcoplasmic Reticulum
A membrane-bound structure within muscle cells that stores and releases calcium ions to trigger muscle contraction.
Myofibrils
Rod-like units of muscle cells composed of long chains of sarcomeres, responsible for muscle contraction.
Action Potential
A rapid, temporary change in a cell's membrane potential, crucial for nerve impulse transmission and muscle contraction.
- Understand the biochemical and physical processes involved in muscle contraction and movement
Verified Answer
MJ
Music journey explorerJul 28, 2024
Final Answer :
B
Explanation :
When an action potential arrives in the muscle cell, it travels down the T-tubules which are invaginations of the sarcolemma (cell membrane) that allow the action potential to reach the sarcoplasmic reticulum (SR). The SR then releases stored calcium ions into the cytoplasm of the muscle cell. This calcium release triggers the contraction of the muscle fibers. Therefore, the correct answer is B - calcium is released by the sarcoplasmic reticulum in response to an action potential.
Learning Objectives
- Understand the biochemical and physical processes involved in muscle contraction and movement