Physiological refers to the normal, healthy operation of your body and its organs.
You know that the root word of physiological is phys, which refers to the body (ah, all those phys. ed. classes you panted through). That root comes from the Greek word for nature. Add the suffix ology, which means "the study of" (see where we're going?), and finally, tack on that little ical. Ta-taa! You have turned the root into an adjective to describe the way your body should work. Let's get physiological!
