Related topics: brain cells
Human brain
hideThe human brain is the center of the human nervous system and is a highly complex organ. Enclosed in the cranium, it has the same general structure as the brains of other mammals, but is over three times as large as the brain of a mammal with an equivalent body size. Most of the expansion comes from the cerebral cortex, a convoluted layer of neural tissue that covers the surface of the forebrain. Especially expanded are the frontal lobes, which are involved in executive functions such as self-control, planning, reasoning, and abstract thought. The portion of the brain devoted to vision is also greatly enlarged in humans.
Brain evolution, from the earliest shrewlike mammals through primates to hominids, is marked by a steady increase in encephalization, or the ratio of brain to body size. The human brain has been estimated to contain 50–100 billion (1011) neurons[citation needed], of which about 10 billion (1010) are cortical pyramidal cells.[citation needed] These cells pass signals to each other via approximately 100 trillion (1014)[citation needed] synaptic connections.
In spite of the fact that it is protected by the thick bones of the skull, suspended in cerebrospinal fluid, and isolated from the bloodstream by the blood-brain barrier, the delicate nature of the human brain makes it susceptible to many types of damage and disease. The most common forms of physical damage are closed head injuries such as a blow to the head, a stroke, or poisoning by a wide variety of chemicals that can act as neurotoxins. Infection of the brain is rare because of the barriers that protect it, but is very serious when it occurs. More common are genetically based diseases[citation needed], such as Parkinson's disease, multiple sclerosis, and many others. A number of psychiatric conditions, such as schizophrenia and depression, are widely thought to be caused at least partially by brain dysfunctions, although the nature of such brain anomalies is not well understood.
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News tagged with human brain
Scientists discover 2 genes that drive aggressive brain cancers
15 hours ago |
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A team of Columbia scientists have discovered two genes that, when simultaneously activated, are responsible for the most aggressive forms of human brain cancer.
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Protein link may be key to new treatment for aggressive brain tumor
Dec 22, 2009 |
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Biomedical researchers at the University of Central Florida have found a protein that could hold the key to treating one of the most common and aggressive brain tumors in adults.
Microcephaly genes associated with human brain size
Dec 21, 2009 |
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A group of Norwegian and American researchers have shown that common variations in genes associated with microcephaly - a neuro-developmental disorder in which brain size is dramatically reduced - may explain differences ...
Why newborn babies can't walk
Medicine & Health / Neuroscience
Dec 18, 2009 |
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(PhysOrg.com) -- The first steps of an infant is a real milestone in the development of all mammals including humans, but little is known about why some animals can walk soon after birth, while others need ...
New human reproductive hormone could lead to novel contraceptives
Dec 22, 2009 |
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(PhysOrg.com) -- Nearly 10 years after the discovery that birds make a hormone that suppresses reproduction, University of California, Berkeley, neuroscientists have established that humans make it too, opening ...
Fish fatty acids don’t make you cleverer or happier
Dec 22, 2009 |
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(PhysOrg.com) -- A diet rich in fish fatty acids has no effect on cognitive functions such as memory and concentration in the elderly. Nor does it affect their level of wellbeing. This is the conclusion drawn by Dutch researcher ...
Subtle change dramatically reduces pathogenic potential of Huntington's protein
17 hours ago |
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Scientists have identified a key molecular switch that may drive the onset of Huntington's disease (HD), an incurable neurodegenerative disorder that leads to severe disruptions in muscle coordination and cognitive function. ...
Understanding relationship of proteins, fatty acids could help treat diseases
Dec 22, 2009 |
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(PhysOrg.com) -- It's widely understood that eating a diet high in saturated fats increases the risk for a long list of chronic and deadly diseases, including diabetes and coronary heart disease. Understanding ...
Chemistry makes the natural 'wonder fabric' -- wool -- more wonderful
Nanotechnology / Nanomaterials
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Scientists in China are reporting an advance that may improve the natural wonders of wool — already regarded as the "wonder fabric" for its lightness, softness, warmth even when wet, and other qualities. They ...
Researcher explains mystery of golden ratio
Dec 21, 2009 |
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The Egyptians supposedly used it to guide the construction the Pyramids. The architecture of ancient Athens is thought to have been based on it. Fictional Harvard symbologist Robert Langdon tried to unravel ...
Privacy concerns could limit benefits from real-time data analysis, researcher says
Technology / Computer Sciences
Dec 17, 2009 |
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Society will be unable to take full advantage of real-time data analysis technologies that might improve health, reduce traffic congestion and give scientists new insights into human behavior until it resolves questions about ...
List of search results for human brain
