10 things you need to know about the body

Our bodies are complex, mysterious, miraculous things. Dr Bridie O'Donnell tells us how they tick.

Written by Dr Bridie O'Donnell

Making positive changes to our health starts with understanding the human body. So many complex systems work together to keep us feeling vibrant and strong, and it all happens beneath the surface.

As part of the Medibank School of Better – a free online learning space designed to give you the knowledge and skills to live better each day – medical doctor and former pro cycling champion Dr Bridie O'Donnell leads a short, practical course on how the body works, preventing disease and increasing physical health.

Here, she shares some essential facts about the building blocks of the human body.

Your cells know what they want to be

All human cells are set from the beginning of their lives to develop into specific types. They grow in size, multiply in number and connect to each other to become the tissues and organs of our body.

Your body is (sometimes) great at healing itself

Some organ systems have the ability to regenerate and repair themselves and others do not.

Your height is set as a teenager

Our greatest rate of growth occurs around the time of puberty. We usually reach our adult height by 14-15 years of age for girls and 17-18 years of age for boys.

All different shapes and sizes are 'normal'

There is a wide variety in the stature, shape and size of bodies across our diverse community. This depends on many factors including gender, race, chromosomal abnormalities, nutrition during childhood, exposure to sport, and childhood illness.

We are full of water

Our body is composed of approximately 55% water, with the average adult woman approximately 50% water and man approximately 60% water. This water is in all the cells of our body in different amounts.

Which means hydration is essential

We need to consume around two litres of water on a daily basis to ensure adequate hydration of all these cells and to allow our organ systems to perform at their optimum level.

There are many elements that make up general good health

When doctors make a general assessment of good health, we are making note of features in your body that demonstrate adequate nutrition, hydration and appropriate strength and coordination in the way you move.

Nerves help the body communicate with the brain

Our body systems connect to our brain via nerves to give us feedback and signals when we’re in pain, or when damage is being done to our tissues. These are called symptoms.

Visible changes in the body can indicate health issues

The visible evidence of injury or illness to our bodies may be a change in size, shape, colour, feeling or function. These are called signs.

Your doctor takes all of this into consideration

When you see a doctor about a medical problem, we use your history, symptoms, signs and examination to determine a likely diagnosis and management plan.

Want to learn more about the body? Head to the Medibank School of Better, where Dr Bridie O'Donnell takes you through some short, practical lessons on how the body works.

Written by Dr Bridie O'Donnell

Dr Bridie O’Donnell is a medical doctor and educator at Epworth Health Check, National and Oceania cycling champion and doctor on The Project.

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