Physiological systems are groups of organs and structures that work together to perform specific functions essential for maintaining life. Examples include the circulatory system, which transports blood and nutrients, and the nervous system, which coordinates body activities through signals. Each system plays a vital role in overall health and homeostasis. These systems interact with one another to ensure the body operates smoothly. For instance, the respiratory system provides oxygen to the circulatory system, which then delivers it to cells throughout the body. Understanding these systems helps in studying how the body responds to various conditions and maintains balance.