ANATOMY

Detailed explanation-1: -The human brain has often been viewed as outstanding among mammalian brains: the most cognitively able, the largest-than-expected from body size, endowed with an overdeveloped cerebral cortex that represents over 80% of brain mass, and purportedly containing 100 billion neurons and 10× more glial cells.

Detailed explanation-2: -Remarkably, at an average of 86 billion neurons and 85 billion nonneuronal cells (25), the human brain has just as many neurons as would be expected of a generic primate brain of its size and the same overall 1:1 nonneuronal/neuronal ratio as other primates (26).

Detailed explanation-3: -For half a century, neuroscientists thought the human brain contained 100 billion nerve cells. But when neuroscientist Suzana Herculano-Houzel devised a new way to count brain cells, she came up with a different number-86 billion.

Detailed explanation-4: -The nervous system is composed of more than 100 billion cells known as neurons. A neuron is a cell in the nervous system whose function it is to receive and transmit information.