Answer:
The depolarization of the smooth muscle cell membranes triggers the potential for contraction action, since the endoplasmic reticulum releases calcium in the intraplasmic zone, causing myosin and actin to unite, generating a sweeping movement and bringing the z lines of the sarcomero.
Smooth muscle contractions are more sustained over time by the distribution and type of muscle fiber, as they are more tapered.
Explanation:
The smooth muscle is that muscle that controls non-voluntary contractions, that is, controlled by the somatic nervous system, and is not related to locomotion but rather to involuntary movements such as intestinal motility, vascular contraction, etc.
The sliding of myosin and actin filaments over one another causes smooth muscle contraction. The hydrolysis of ATP provides the energy for.
Smooth muscle lacks the calcium-binding protein troponin, which is found in cardiac and skeletal muscle. Smooth muscle fibers, unlike skeletal muscle fibers, usually contract slowly and synchronously. The electrical connection of smooth muscle by gap junctions causes the smooth muscle fibers to synchronize.
When the communication from the motor neuron stops, the sarcolemma and T-tubules repolarize, and the voltage-gated calcium receptors in the sarcoplasmic reticulum shut. Ca++ ions are subsequently returned to the sarcoplasmic reticulum, causing tropomyosin to re-cover the actin strands' binding sites. When a muscle runs out of ATP and becomes exhausted, it might also stop contracting.
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