Answers for the Your Amazing Brain quiz

How much did you know about Your Amazing Brain?  If you would like to learn more about the brain, there is some great information on the web.  The US Alzheimer's Association has a Brain Tour that explains how the brain works and how it is affected by Alzheimer's disease.  And the Society for Neuroscience provides Brain Facts in downloadable booklet and audio formats.

Here are the correct answers to our brain quiz.

Q. 1  What does an average human brain weigh?

  1. 14 grams
  2. 1.4 kilograms
  3. 14 kilograms

The correct answer is 2. The average adult human brain weighs around 1.3 to 1.4 kilograms. That’s about the weight of a small Chihuahua. Some people are above average though. The brain of Russian poet Surgeyevitch Turgenev weighed over 2 kilograms. When you were born, your brain already weighed about a quarter of its adult weight.

Q. 2  Neurons are the brain cells that do all the work to keep you moving and thinking. How many neurons are there in your brain?

  1. 100
  2. 100 million
  3. 100 billion

The correct answer is 3. There are around 100 billion neurons in the average human brain. You were born with around the same number of neurons, but they grew bigger reaching their maximum size at around age six. Keep exercising your brain, because mental activity stimulates the creation of new neurons throughout your life.

Q. 3  As your brain developed during early pregnancy, how fast did your neurons multiply?

  1. 250,000 per minute
  2. 250,000 per hour
  3. 250,000 per day

The correct answer is 1. In the early stages of human brain development, 250,000 new neurons are created every minute. Newly generated neurons migrate to different parts of the developing brain to organise into different brain structures. They grow axons (nerve fibres) which allow them to communicate with other neurons.

Q. 4  Which side of your brain has more neurons?

  1. Right
  2. Left
  3. Both the same

The correct answer is 2. On average there are 186 million more neurons on the left side of the brain than the right side. That’s because most of us are left brain dominant. This means that our language skills are looked after by the left hemisphere of the brain, and mostly we are right handed (the left side of the brain controls the right side of the body). Very few people are truly right brain dominant, with their language centres in the right hemisphere.

Q. 5  A synapse is a connection between two neurons through which they communicate. How many synapses does a typical neuron have?

  1. 10 to 20
  2. 100 to 500
  3. 1,000 to 10,000

The correct answer is 3. Most of your neurons connect to between 1,000 and 10,000 neighbouring neurons. Chemical signals are transmitted across the synapse from one neuron to another and converted to electrical signals that are carried along the nerve fibre to the next synapse. Sounds simple, but this process is responsible for all the amazing things your brain achieves.

Q. 6  What is the total length of all the nerve fibres in your brain?

  1. 1 to 2 kilometres
  2. 3000 to 5000 kilometres
  3. 150,000 to 180,000 kilometres

The correct answer is 3. If you laid out all the nerve fibres in your brain end to end they would stretch for 150,000 to 180,000 kilometres. That’s approximately 4 times around the circumference of the Earth.

Q. 7  How fast can information travel in your brain?

  1. Up to 120 metres per second
  2. Up to 120 metre per minute
  3. Up to 120 metres per hour

The correct answer is 1. Information travels at different speeds within different types of neurons. Transmission can be as slow as 0.5 metres per second and as fast as 120 metres per second. The top speed is equivalent to 432 kilometres per hour.

Q. 8  What proportion of the oxygen pumped around your body is used by your brain?

  1. 5%
  2. 20%
  3. 50%

The correct answer is 2. Your brain is only about 2% of your body weight, but it gets about 20% of the blood pumped from your heart and uses up about 20% of the total oxygen carried in your bloodstream. Regular physical exercise increases blood flow and helps keep your blood vessels and your brain healthy.

Q. 9  How long before you lose consciousness after losing blood supply to your brain?

  1. 1 to 2 seconds
  2. 8 to 10 seconds
  3. 20 to 25 seconds

The correct answer is 2. If blood supply to your brain is lost for any reason, you will lose consciousness within 8 to 10 seconds. Your brain needs a constant supply of oxygen and glucose from your blood in order to function.

Q. 10  In ancient Egypt, the brain was removed from the body before mummification. How was it removed?

  1. Through the nose
  2. Through the mouth
  3. Through a hole cut in the skull

The correct answer is 1.  The ancient Eqyptians thought the brain served no purpose.  so, before mummifying a body, the brain was mashed and pulled out through the nose using hooks, and discarded.  Other organs were carefully removed and stored in jars to be looked after by the gods.



Call the National Dementia Helpline on 1800 100 500 for questions, information, advice.


Your Brain Matters was supported by funding from the Australian Government under the Chronic Disease Prevention and Service Improvement Fund from July 2012 to June 2015.



Dementia Australia would like to acknowledge the Aboriginal people as the traditional custodians and carers of the country of Australia.