Brain, portion of the central nervous system contained within the skull. The brain is the control center for movement, sleep, hunger, thirst, and virtually every other vital activity necessary to survival. All human emotions—including love, hate, fear, anger, elation, and sadness—are controlled by the brain. It also receives and interprets the countless signals that are sent to it from other parts of the body and from the external environment. The brain makes us conscious, emotional, and intelligent. Brain is an organ as well and thus composed of cells. Brain cells are connected to nerve cells called neurons.
Neurons are shaped like flowers wherein its stems are called axons and its petals are called dendrites. Basically neurons are connected to each other via dendrites and its axon is latched to muscles or sensory muscles. Brain achieves control over the whole body via synapses. Synapses refer to electrical signals between neurons and brain cells. It is believed that learning is caused by these synapses between brain cells. That is the more synapses, the brain is experiencing greater activity. Most high-level brain functions take place in the cerebrum. Its two large hemispheres make up approximately 85 percent of the brain's weight. The exterior surface of the cerebrum, the cerebral cortex, is a convoluted, or folded, grayish layer of cell bodies known as the gray matter. The gray matter covers an underlying mass of fibers called the white matter. The convolutions are made up of ridgelike bulges, known as gyri, separated by small grooves called sulci and larger grooves called fissures. Other parts of the brain are cerebellum and medulla oblongata.
Posted 2011-01-29 and updated on Jun 08, 2011 3:11pm by crisd