El Cerebro (Inglés)

The brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few invertebrates such as sponges,jellyfish, adult sea squirts and starfish do nothave one, even if diffuse neural tissue is present. It is located in the head, usually close to the primary sensory organs for such senses as vision, hearing, balance, taste, and smell. The brain of avertebrate is the most complex organ of its body. In a typical human the cerebral cortex (the largest part) is estimated to contain 15–33 billion neurons,[1] each connected by synapses to severalthousand other neurons. These neurons communicate with one another by means of longprotoplasmic fibers called axons, which carry trains of signal pulses called action potentials to distant parts of thebrain or body targeting specific recipient cells.
Physiologically, the function of the brain is to exert centralized control over the other organs of the body. The brain acts on the rest of the bodyboth by generating patterns of muscle activity and by driving secretion of chemicals called hormones. This centralized control allows rapid and coordinated responses to changes in the environment. Somebasic types of responsiveness such as reflexes can be mediated by the spinal cord or peripheral ganglia, but sophisticated purposeful control of behavior based on complex sensory input requires theinformation-integrating capabilities of a centralized brain.
From a philosophical point of view, what makes the brain special in comparison to other organs is that it forms the physical structure thatgenerates the mind. As Hippocrates put it: "Men ought to know that from nothing else but the brain come joys, delights, laughter and sports, and sorrows, griefs, despondency, andlamentations."[2] Through much of history, the mind was thought to be separate from the brain. Even for present-day neuroscience, the mechanisms by which brain activity gives rise to consciousness and thought remain very...