Spindle fibers are protein structures that form early in mitosis, or cell division. They consist of microtubules that originate from the centrioles, two wheel-shaped bodies located in the centromere area of the cell. The centromere is also known as the microtubule organizing center.
1 Night terrors are characterized by frequent recurrent episodes of intense crying and fear during sleep, with difficulty arousing the child. Night terrors are frightening episodes that disrupt family life.  A small percentage of children experience night terrors.
Nighttime (nocturnal) panic attacks can occur with no obvious trigger and awaken you from sleep. As with a daytime panic attack, you may experience sweating, rapid heart rate, trembling, shortness of breath, heavy breathing (hyperventilation), flushing or chills, and a sense of impending doom. These signs and symptoms are quite alarming and can mimic those of a heart attack or another serious medical condition. Although nocturnal panic attacks usually last only a few minutes, it may take a while to calm down and go back to sleep after you have one.