http://en.wikipedia.org/wiki/Human_brain
The human brain is composed of neurons, glial cells, and blood vessels. The number of neurons, according to array tomography, a technique far more accurate than earlier microscopic methods, has shown about 200 billion neurons in the human brain with 125 trillion synapses in the cerebral cortex alone.
The human brain is composed of neurons, glial cells, and blood vessels. The number of neurons, according to array tomography, a technique far more accurate than earlier microscopic methods, has shown about 200 billion neurons in the human brain with 125 trillion synapses in the cerebral cortex alone.
Development
During the first 3 weeks of gestation, the human embryo's ectoderm forms a thickened strip called the neural plate. The neural plate then folds and closes to form theneural tube. This tube flexes as it grows, forming the crescent-shaped cerebral hemispheres at the head, and the cerebellum and pons towards the tail.
Brain of human embryo
at 4.5 weeks, showing interior of forebrain
Brain interior at 5 weeks
Brain viewed at midline at 3 months
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