The Brain and Skull

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A diagram showing the functional areas of a human brain

The brain is the part of the body's nervous system which lets us, including animals, make sense of things and is thus the entire body's control system.[1] It gets its input from sensory organs, and changes behavior in response to this information. In humans, the brain also controls our use of language, and is capable of abstract thought.[2] The brain is made up of a special type of cells, simply called brain cells. They are connected with each other and with the nerves in our body. In all animals the delicate brain is protected in some way, but in ourselves and all other vertebrates, it is protected by the bones of the skull, which is a complex of several bones (the most well-known of which is the cranium) that surround and protect the brain, as said before.

Function of the Brain and Skull

Diagram showing the location of the main bones in an adult's skull

The brain, as said before, does the thinking, learning, and feeling for the body. For humans, it is known to be the source of consciousness. The brain also partly controls basic automatic body actions, like breathing, digestion, and the beating of the heart. These activities, and much else, are controlled by unconscious functions of the brain and the rest of the nervous system. All the information about the world we know is gathered by our senses and is sent through nerves into the brain, allowing us to see, hear, smell, taste and feel things. The brain processes this information, and we experience it as pictures, sounds, and so on. The brain also uses nerves to tell the body what to do, an example of this is telling muscles to move or the muscles in our heart to beat faster.

The skull is the set of bones that surround the brain in order to protect it from damage. Not only that, the skull fixes the distance between the eyes and between the ears. This allows stereoscopic vision, and helps help the brain judge direction and distance of sounds. In some animals, the skull also has defensive functions. The skull is made out of several flat bones fused together. In humans, the adult skull is normally made up of 28 bones.

Structure of the Brain

In all mammals, the brain is made of three main parts: the cerebrum, the cerebellum and the brain's stem. The surface of the cerebrum is the cerebral cortex, which all vertebrates have. Mammals, compared to other animals, also have an extra layer, the neocortex. This is the key to the behavior which is typical of all mammals, including humans.

Cerebral cortex

The cortex has sensory, motor, and association areas. The sensory areas, for obvious reasons, are the areas that receive and process information gathered from the senses. The motor areas control voluntary movements, especially those performed by hand. Weirdly, he right half of the motor area controls the left side of the body, and the left side of the motor area controls the right side of the body! The association areas produce a meaningful experience of the world, and supports abstract thinking and language. This enables us to interact effectively. Most connections are from one area of the cortex to another, rather than to subcortical areas; The figure may be as high as 99%.[3]


The Cerebellum coordinates the muscles so that they work together. It is also the center of maintaining your position and balance, and an essential part of movement helping with simple motor skills.

Stem of the brain

The brain's stem is located underneath it in humans. It joins the rest of the brain with the spinal cord. It has lots of different parts that control different jobs in the body: for instance, the brain stem controls breathing, heartbeat, sneezing, eye blinking, and swallowing of food. Body temperature and hunger are also controlled by parts of the brain stem.

Size of the Brain

The size of the average human brain is around 15 centimeters in length.


  1. ISBN 1740893298
  2. ISBN 0753802007
  3. Braitenberg V. and Schüz A. 1991. Anatomy of the cortex: statistics and geometry. NY: Springer-Verlag.