Final answer:
Menstrual cycle synchronization among women who live or work together may be explained by pheromonal communication via the integumentary system, which includes the skin where pheromones are produced and secreted.
Step-by-step explanation:
The observation that women who live or work together often have synchronized menstrual cycles is thought to be related to pheromonal communication, an aspect of the integumentary system. This system includes the skin, where sweat glands and other cells may produce and release pheromones that others can detect, potentially influencing the synchronization of biological rhythms like menstrual cycles. The integumentary system works closely with other systems, like the endocrine system, maintaining homeostasis and responding to hormonal changes, which could account for cyclic synchronization observed in groups of women.
Furthermore, the integumentary system's role in thermoregulation is indicative of its capacity to respond to and communicate changes in the body's internal state. While there is still debate regarding the extent to which humans rely on pheromonal cues compared to other mammals, these chemical signals could indeed play a role in the phenomenon of synchronized menstrual cycles.