The brain is the most complex organ in the human body but yet accounts for only 2 percent of its weight, according to the University of Washington. The brain, along with the spinal cord, makes up the central nervous system. The University of Washington reports that the brain has over 100 billion nerve cells, called glia, which are responsible for sending and receiving messages to all parts of the body. The brain is divided into two halves: the right hemisphere and the left hemisphere. In addition, there are several different areas of the brain each responsible for different functions.
Memory
Humans are fortunate to have the ability to learn and remember, and it is the brain and its capacity that allows for that. Specifically, it is the limbic system found in the cerebellum which contains the hippocampus that is responsible for the ability to retain information. When people think of the brain, learning and memory are the first functions that come to mind. Although this is an important function, there are many other vital functions the brain performs.
Processing Sensory Input
The environment is full of stimulation--sights, colors, sounds, textures and tastes. The reason we can see, hear, touch and taste is because the sensory nerves send signals to the brain where it is processed. The thalamus receives almost all the sensory input and then sends it to the cerebral cortex, where the signals are processed.
Movement
The cerebellum, which in Latin means "little brain", is located just behind the brain stem. The cerebellum is the center of movement, balance and posture. When you need to move your arm in order to pick up an object, the nerves in the cerebellum send signals down the spinal cord and to that specific muscle to contract and relax. The cells in the muscles then send signals to inform the brain the level of contraction.
Emotional Response
The brain is also responsible for controlling emotions and the way we respond to our surroundings. The area of the brain known as the limbic system is often referred to as the "emotional brain", according to Serendip. The limbic system includes the thalamus, hypothalamus, amygdala and hippocampus.
Vital Life Functions
The brain stem is the portion of the brain from the thalamus to the spinal cord. This part of the brain is considered the simplest part, according to Serendip, because it closely resembles the brains of lower animals such as reptiles. The brain stem is responsible for controlling those functions that are vital to life. This includes breathing, heartbeat and blood pressure.
