The human brain contains more than 100,000,000,000 neurons (100 billion) at birth.
- By 8 months of age, the human brain has established over 1,000 trillion connections (synapses).
- The number of connections decline with age, an adult brain has around 100 trillion connections.
- On average 1 neuron has 7,000 different synaptic connections to other neurons
- The longest axon of a human neuron can be over a meter long, reaching from the base of the spine to the toes.
- Rate of neuron growth (early pregnancy) = 250,000 neurons/minute
- Average weight of the human brain = 1300-1400g (3 pds)
- New born human brain = 350-400g (12 oz) – Approx. 25% of adult weight
- Weight of the brain at 6 months = 50% of its adult weight
- Weight of the brain at 30 months = 75% of its adult weight
- Cerebral cortex at age 5 (before school) = 90% of its adult weight
- Percent of total body weight that the brain represents = 2% (avg)
- Percent of body’s oxygen consumed by the brain = 25%
- Percent of body’s glucose burned up by the brain = 70% (avg)
- Percent of body’s nutrients consumed by the brain = 25%
- Distance of blood vessels and other transport systems in the brain = 160,000km (100,000 miles)