By Tanya Lewis, Staff Writer; March 25, 2016 2:51pm ET
The human brain is the command center for the human nervous system. It receives input from the sensory organs and sends output to the muscles. The human brain has the same basic structure as other mammal brains.The largest part of the human brain is the cerebrum, which is divided into two hemispheres. Underneath lies the brainstem, and behind that sits the cerebellum. The outermost layer of the cerebrum is the cerebral cortex, which consists of four lobes: the frontal lobe, the parietal lobe, the temporal lobe and the occipital lobe.Like all vertebrate brains, the human brain develops from three sections known as the forebrain, midbrain and hindbrain. Each of these contains fluid-filled cavities called ventricles. The forebrain develops into the cerebrum and underlying structures; the midbrain becomes part of the brainstem; and the hindbrain gives rise to regions of the brainstem and the cerebellum.
Left brain vs. Right brain
right brain left brain
The human brain is divided into two hemispheres, the left and right, connected by a bundle of nerve fibers called the corpus callosum. The hemispheres are strongly, though not entirely, symmetrical. The left brain controls all the muscles on the right-hand side of the body; and the right brain controls the left side. One hemisphere may be slightly dominant, as with left- or right-handedness.The popular notions about "left brain" and "right brain" qualities are generalizations that are not well supported by evidence. Still, there are some important differences between these areas. The left brain contains regions involved in speech and language (Broca's area and Wernicke's area), and is also associated with mathematical calculation and fact retrieval. The right brain plays a role in visual and auditory processing, spatial skills and artistic ability — more instinctive or creative things, though these functions involve both hemispheres.
Facts about the human brain
The human brain is the largest brain of all vertebrates relative to body size
It weighs about 3.3 lbs. (1.5 kilograms)
The brain makes up about 2 percent of a human's body weight
The cerebrum makes up 85 percent of the brain's weight
Facts about the human brain
It contains about 86 billion nerve cells (neurons) — the "gray matter"
It contains billions of nerve fibers (axons and dendrites) — the "white matter"
These neurons are connected by trillions of connections, or synapses
The main differences between human and animals brains is their size
