Brain: Neuron Growth
This diagram shows the neurons, or nerve cells, in the brain of a newborn baby. The dark triangular or circular parts of the diagram represent the cell body of the neurons. The long threadlike lines represent the axons and dendrites, which are the parts of the neurons that connect with other neurons.
What to Do Here:
Click the play button to see what happens to the neurons in the brain as a child grows from newborn to 2 years old.
Questions to Consider:
- What changes happen in the brain as the child gets older?
- How many connections to other neurons does each neuron have when a baby is first born?
- How many connections to other neurons does each neuron have when a child is 2 years old?
Tidbits:
A baby's brain has many more neurons than it needs, about 100 billion in a newborn brain. As a baby grows and learns, no new neurons form in the brain. Rather, new connections grow between existing neurons, to create and strengthen pathways that carry messages from the body to the brain and back, as well as within the brain itself.
A baby's brain will grow to three times its original size in the first year of life. This increase is from the growth of dendrites and axons as they form connections between existing neurons, not from new neurons.
Just like in a baby's brain, when you learn something new, new pathways form between neurons in your brain. Whenever you practice that new skill or think in the same way, the pathway and connections between those neurons grow stronger. That's why, with practice, it becomes easier to remember the things you have learned.
The typical human brain has 60 to 100 billion neurons. Each of these can connect to hundreds, thousands, or even hundreds of thousands of other neurons. The huge number of pathways of neural activity that results is somehow responsible for everything you learn, remember, say, see, and do—in fact, everything that makes you human.