Why study ourselves?
Humans are living things, so the same rules of biology apply to us: we need food, air and water, we grow, and we can fall sick. A group of sciences studies the human body from different sides. The three main ones are anatomy, physiology and hygiene.
Anatomy: how the body is built
Anatomy studies the structure of the body: its organs, their shape, size and position. For example, the heart lies a little left of the middle of the chest, between the two lungs; the brain is inside the skull; the stomach is below the lungs. Anatomists look at parts with the eye, with a microscope and with images such as X-ray and ultrasound. Question it answers: What is it and where is it?
Physiology: how the body works
Physiology studies the work (functions) of organs and how they cooperate. The heart pumps blood about 70 times a minute at rest; lungs bring in oxygen; kidneys clean the blood. When you run, muscles need more oxygen, so the heart beats faster and you breathe faster. Question it answers: How does it work and why?
Hygiene: how to stay healthy
Hygiene studies the rules and habits that keep us healthy and prevent disease. These include washing hands with soap before meals and after the toilet, clean drinking water, brushing teeth, clean food, enough sleep and exercise, and a tidy home. Germs on a hand can be washed off with soap in about 20 seconds. Question it answers: What should I do to stay well?
Methods: how do we find out?
Scientists use three simple methods:
- Observation: look carefully, with the eye or a microscope, and write what you see.
- Measurement: use numbers, such as pulse, height, body temperature and weight.
- Experiment: change one thing and compare, for example pulse at rest and after one minute of running. Keep everything else the same so the test is fair.
Other methods are asking questions in a survey, using machines like ECG and X-ray, and comparing healthy people with sick ones.
Who uses these sciences? Professions
Doctor, surgeon and radiologist (reads images) use anatomy. Physiologist, sports scientist and physiotherapist use physiology. Nurse, public-health officer, dietician and food-safety inspector use hygiene. Many jobs use all three.
Try it
Try it (with an adult): sit calmly for one minute. Find your pulse on the wrist, count beats for 15 seconds and multiply by 4. Run on the spot for one minute and count again. Write both numbers. Which science are you using: anatomy, physiology or hygiene?
Key formulas and definitions
- Anatomy = structure (what and where)
- Physiology = function (how it works)
- Hygiene = health habits (how to stay well)
- Pulse per minute = beats in 15 s × 4
- Methods: observe, measure, experiment
Worked examples
1. A doctor looks at an X-ray to see a broken bone. Which science is this?
It is about structure, so anatomy.
2. A coach finds that a runner's pulse rises from 70 to 125 beats per minute. Which science, and what changed?
Physiology. The pulse rose by 125 - 70 = 55 beats per minute because muscles needed more oxygen.
3. A student counts 18 pulse beats in 15 seconds. What is the pulse per minute?
18 × 4 = 72 beats per minute.
4. Why is washing hands before eating a hygiene rule?
It removes germs from the hands so they do not enter the mouth and cause disease.
Common mistakes
- Mixing up anatomy and physiology. Anatomy = structure; physiology = working.
- Thinking hygiene only means being clean-looking. It means habits that stop disease.
- Changing many things in an experiment. Change only one so the result is fair.
- Counting the pulse for 15 seconds and forgetting to multiply by 4.