The brain is an incredibly complex and important organ. It affects almost every aspect of our day-to-day lives, from basic bodily functions like breathing to higher cognitive skills like communication. The complexity of the brain, however, is both a blessing and curse. On one hand, it allows humans to achieve intellectual feats unequaled by any other animal species on earth. On the other hand, it makes the brain a very delicate organ. Even apparently minor injuries to the brain can have significant and long-lasting effects on a person's mental and physical health.

A Vital Organ

Because the brain is so important to the functions and survival of the human body, the body has, in turn, developed several layers of support and defense designed to nourish and protect the brain. For example, the brain receives a disproportionate amount of oxygen and blood flow - approximately 20% of the total amount used by the body. This is remarkable, when one considers that the brain only accounts for 2-3% of the body's total mass. What this also tells us is that the brain needs a very large amount of oxygen to survive. Brain cells can begin to die off after only 3 minutes without sufficient oxygen.

Defense Mechanisms

The brain and central nervous system are insulated and protected by a variety of bodily defense. To begin with, they are enveloped by a series of three membranes collectively known as the meninges. The outermost and toughest of the three meninges is called the dura mater. Underneath it is the arachnoid mater, characterized by a spidery, web-like appearance. The arachnoid mater functions as a type of shock-absorber for the brain. The innermost layer of the meninges is the pia mater, which is a very thin membrane responsible for providing nourishment to brain matter.

Between the inner layer (pia mater) and the middle layer (arachnoid mater) of the meninges is a gap known as the subarachnoid space, filled with cerebrospinal fluid, or CSF. CSF is a clear, watery fluid which provides cushioning to the brain, as well as a rudimentary barrier against harmful microorganisms. The brain essentially floats inside this liquid shock-absorber.

A final layer of defense for the brain is the skull. Often overlooked (paradoxically) because it is so obvious, the skull is actually, in most cases, a very effective form of defense against physical trauma. Contrary to what many people think, the human skull is not a solid piece of bone. Instead, it is composed as a sort of jigsaw puzzle of 22 bone pieces joined together by rigid sutures.