Answer
Among humans, as among all other animals, no two individuals are exactly the same in anatomy or in physiology. Textbooks usually have drawings representing human structures, and values representing normal physiological values. But these are just typical, or average, or most common values; they do not apply to every individual human, exactly. Medical students and nursing students need to be aware of this or they will be in for some surprises. Physicians who do not keep these variations in mind may harm patients by applying normal values to all patients.
Work Step by Step
Physiological values vary widely in humans according to age, weight, sex, diet, physical activity,and living environment. When a patient goes to a healthcare provider, the following parameters are usually assessed; blood pressure, heart rate, hematocrit, red blood cell count, WBC count and body temperature. The values obtained are then compared against what are certain typical ranges used in every clinic. Usually, healthcare professionals make adjustments for sex, and age ( very young and very old) , and a few make adjustment for socioeconomic status, and racial/ethnic identity. It is still true, nevertheless, that not all white American women 32 years old and five feet four inches tall have the heart rate , respiratory rate or blood pressure . The same is true for all Latino American men of the same age and approximate weight and height. People have variations-- based on gene mutations and embryogenesis-- that ensure that no two people are exactly alike either in anatomy or in physiology or metabolism--though identical twins come close.
The parameters used as standards in clinical exams usually relate to a person with the following characteristics:
Healthy Caucasian, 22 years old; life time of moderate physical activity:
weight male 154 lbs, female 128 lbs; caloric intake male 2800 kcal/day female 2000 kcal/day.
Most people do not conform to this model. Yet it is expensive and time consuming to practice individualized medicine. Nevertheless, computerized medicine is making it easier to take into account increasingly more and more of the individual human variations. This will make for safer and more effective medical practice.
