Shortcut Methods
- Mechanism of Contraction:
- Neural Stimulation: Initiated by a signal from a motor neuron.
- Neurotransmitter Release: Acetylcholine is released at the neuromuscular junction, triggering an action potential in the muscle fiber.
- Action Potential: Travels along the muscle fiber’s membrane and into the fiber through the T-tubules.
- Calcium Release: Action potential triggers the sarcoplasmic reticulum to release calcium ions.
- Actin-Myosin Interaction: Calcium ions bind to troponin, moving tropomyosin, and exposing binding sites on actin. Myosin heads bind to these sites, forming cross-bridges.
- Power Stroke: Myosin heads pivot, pulling actin filaments towards the sarcomere center. This shortens the muscle fiber.
- ATP Role: ATP binds to myosin, detaching it from actin and providing energy for the cycle to repeat.
