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.
Night Terrors. Night terrors occur most often in toddlers and preschoolers and take place during the deepest stages of sleep. Deepest sleep is usually early in the night, often before parents' bedtime. During a night terror, your child might: