The brain is _____ at work when you’re sleeping.

The brain’s structure is constantly changing as we learn. New neuronal connections are made which increases the _____ of the brain.

The fastest signal transmission in the body occurs in the alpha motor neurons within the spinal cord. They transmit a signal at _____ miles per hour. The slowest signal transmission is within the skin at 1 mile per hour.

We lose neurons as we age, starting at around 20 years old in humans. _____ of our neurons are gone by the time we turn 75.

Males and females have different brain compositions. Males have more _____ matter, while females have more _____ matter.

As we age, our brain shrinks by about _____ grams every year due to the loss of neurons.

The longest nerve in the body is the _____ nerve. It runs from the spinal cord to the toes on each side of the body.

The bowel is controlled by a separate part of the nervous system known as the _____ nervous system. It regulates digestion and bowel movements.

The brain has approximately _____ neurons. In contrast, the spinal cord only has roughly 13.5 million neurons throughout its length.

The brain uses more of the body’s energy than the rest of the organs, using over _____ of the energy reserves in the body.