Normal function. Knowing how the healthy body works helps us to make positive decisions about how to improve our well-being, which includes ways to help us feel good physically and emotionally.

Also, before diseases can be detected (or diagnosed) and corrected (or treated) doctors and veterinarians first of all need to know about norrnal function, including what the signs of normal function are and how they differ from the signs of abnormal function. Some common diagnostic signs used by doctors and veterinarians are the body temperature, heat rate, sounds of breathing, kneejerk reflex, speed of response of the pupil of the eye to light, and the composition of blood and urine. Treating abnormality also requires knowledge of what is normal. By knowing in what way(s) body function differs from normal in sick or injured animals and people, we are better able to work out precisely what is wrong and then begin treatment. Once an illness or injury has occurred, treatments usually aim to cure problems, control problems, or reduce the unpleasant effects using palliative measures. Treatments take different forms which can involve taking medicines, having operations or making lifestyle adjustments like changes in diet, exercise or unhealthy habits like smoking and drug taking.