Anatomy Physiology

The brain is about the size and weight of a grapefruit, has a pinkish color, and has about the same consistency as Jell-O. Scientists once thought that, unlike other organs, the brain was a huge single cell, but we now know that the brain contains between 50 and 100 billion brain cells, also known as neurons.

The human brain consists of several different parts, many of which we share with lower animals. For example, the basic brain structures for emotion, sex drive, movement, and visual object detection are the same in fish, crocodiles, parakeets, pigs, and humans. Progressively more complex species simply have more advanced brain regions “built” on top of the same structures.

The basic brain divisions for humans include the cerebral cortex, cerebellum, limbic system, and brain stem. The cerebral cortex is the center of our ability to think abstractly, plan for the future, and communicate through language. Even rats have a cerebral cortex area, but unlike humans, the cerebral cortex of a rat is only about 2% of the rat’s brain. In humans, the cerebral cortex is the largest part of the brain; it is this part that allows us to learn, think, speak, and be human.

The cerebellum was once thought to be a primitive area of the brain that only assisted the cerebral cortex. However, modern research has revealed that it has implications in almost every motor and sensory process we experience. The cerebellum’s primary function is to help “error check” commands our cerebral cortex sends to our muscles.

The limbic system is an area of the brain that is involved in storing memories, sex drive, emotions, and sense of thirst and hunger. Many of the structures within the limbic system are involved with common neurological and mental illnesses such as bipolar disorder, amnesia, and seizures.

In the 1950’s a man commonly referred to as H.M. underwent surgery to remove part of his limbic system in an attempt to stop him from having severe, life-threatening seizures. However, after H.M.’s surgery doctors and brain scientists learned that this area (known as the hippocampus) was involved in forming new memories. H.M. was not able to learn anything new after his surgery because his brain would not retain memories.

The brain stem is a continuation of the spinal cord and is broken down into three main structures: the midbrain, pons, and medulla. These structures were among the first to develop in ancient, primitive vertebrae. In general, these structures handle the basic functions of keeping us alive, including controlling our heart and breathing rates. Damage to this area is also among the most common causes of death after head injury.

Ultimately everything that we do is linked to the brain and can accordingly be lost due to brain damage. People who can’t speak, hear, walk, and suffer mental illnesses all deserve our empathy and understanding. The next time you judge someone for walking or speaking in a strange way, stop and think about whether they might have suffered brain damage and need your support instead.