 | Stew Biff The brain is the center of the nervous system in animals. All vertebrates, and the majority of invertebrates, have a brain. Some 'primitive' animals such as jellyfishes and starfishes have a decentralized nervous system without a brain, while sponges lack any nervous system at all. In vertebrates, the brain is located in the head, protected by the skull and close to the primary sensory apparatus of vision, hearing, balance, taste, and smell. The human brain appears to have no localized center of conscious control. The brain seems to derive consciousness from interaction among numerous systems within the brain. The human brain controls the central nervous system by way of the cranial nerves and spinal cord, the peripheral nervous system and regulates virtually all human activity. The brain is made up of over 100 billion nerve cells with each brain cell connected to around 10,000 other cells, which equals around 1000 trillion connections in your brain. Your brain is actually very soft, jelly-like, and not grey but a deep red in color. The brain controls both involuntary, or 'lower,' actions, such as heart rate, respiration, and digestion. Complex, or 'higher,' mental activity, such as thought, reason, and abstraction, is consciously controlled. |
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