Your baby’s nervous system controls her body. It comprises her brain, her spinal cord, and her nerves, with billions of neurons (nerve cells). With the brain as the command center, messages from the nerves travel up and down the spinal cord and throughout her body via the neurons to tell the body what to do and how to react. For instance, when the nerves in the skin on your baby’s hand feel something sharp, they send a sensory neuron to the brain to report the sensation. The brain interprets the message and sends a motor neuron back to the hand to tell it to move away from the source of pain.
The brain controls unconscious movements and processes, such as breathing, digestion, sensing, heart rate, blood pressure, balance, and coordination. It also controls conscious movement, memory, intelligence, personality, speech, and emotion.
Your baby is born with nearly all the neurons she will ever have. But at birth, the neurons have yet to connect. As she grows and has experiences, her neurons make connections, or synapses, that create pathways in her brain—a process known as learning.
With practice, tasks that were once new and called for high levels of concentration (such as tying a shoe) become easier because her brain simply follows the pathways for those tasks. With these pathways in place, her brain is free to create more connections and more pathways—thus building more knowledge.
Your baby’s brain and nervous system undergo incredible growth during her first few years. A newborn’s brain accounts for about 25 percent of her approximate adult weight. By age three, the brain has grown close to its adult size through stimulation and the building of synapses.
Your baby’s kidneys govern her nervous system by regulating the balance of sodium and potassium in her cells. Thus, strong kidney function benefits her nervous system. From that perspective, your baby benefits from gentle and regular stimulation of all her senses, as well as attention to and regulation of sugary foods.