Anatomy Physiology

In the movie The Wizard of Oz there is a character known as the Scarecrow who sings a song titled, If I Only Had a Brain. The beginning lyrics are: “I could while away the hours, conferring with the flowers, consulting with the rain. And my head I’d be scratchin’ while my thoughts I’d be hatchin’ if I only had a brain.” Although this was a simple wish of the Scarecrow’s, most likely he had no idea of all the other functions that the brain performs aside from ‘conferring with the flowers’.

These functions are performed by various structures of the brain that are located in the forebrain, the midbrain, and the hindbrain. These five divisions are as follows: telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon.  One may “be scratchin” their head concerning the origin of the names of these structures.  What are all these terms ending in -encephalon?  They come from the Greek encephalon, meaning “brain”.  The en means “in”, and cephalon means “head”; so there you have “that which is in the head”, or in other words, “the brain”.

The telencephalon, the largest division of the human brain, mediates the brain’s most complex functions.   This division is located in the forebrain and can be divided into four sections referred to as lobes: the frontal lobe, parietal lobe, occipital lobe, temporal lobe.  What do each of these lobes do? Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving.  Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli.  Occipital Lobe- associated with visual processing.  Temporal Lobe- associated with perception and recognition of auditory stimuli, memory, and speech.  One with only a small amount of knowledge of the brain is able to understand the terminology and functions of this division of the brain. The other four divisions are often referred to as the brain stem.

The next part of the forebrain is the diencephalon, which is composed of two structures: the thalamus and the hypothalamus.  The thalamus comprises many different pairs of nuclei, most of which project to the cortex.  These are instrumental in processing information between the brain and other areas in the nervous system, such as visual or auditory functions. The hypothalamus lies under the thalamus and not only assists the thalamus but also will play a role in motivated behaviors.

Located in the midbrain is the mesencephalon which has two divisions called the tectum and tegmentum, both having functions concerning parts of the body. The tectum has roles in the visual and audio functions in relaying information. The tegmentum has colorful areas: the periaqueductal gray, the substantia nigra, and the red nucleus. Regulation of the reduction of pain in the reaction to opiate drugs is performed by the periqueductal gray, while the substantia nigra and the red nucleus are components of sensory motor system.

The hindbrain contains the myelencephalon which plays a role in the transmission of information between the brain and the body, such as motor coordination. One may view it as the “go between” for the brain and the body as information is relayed by this division. Included in the regulation of the body functions are: sleep, attention, movement, the maintenance of muscle tone, and various cardiac, circulatory, and respiratory reflexes. Also contained in the hindbrain is the metencephalon which has two divisions, the pons and the cerebellum.   The pons is the bridge to the cerebellum. The cerebellum, which is often referred to as the ‘little brain’, is a very complex structure; and while it is smaller than the cerebral cortex it probably has more neurons.

The brain is a very complicated and almost magical part of the body because the brain, being part of the nervous system, enables the body to perceive what is seen and heard.  These include simple tasks such as to walk or run, or to read a food label.  Also some complicated tasks such as responding to a compliment, or a rude statement; along with millions of other body functions.

So with the words the Scarecrow sang at the end of the song, If I Only Had a Brain, one can perceive the lyrics with meaning concerning the blessing of the human brain:  “I would not be just a nothin’, My head all full of stuffin’, My heart all full of pain.  I would laugh and I’d be merry, Life would be a dinglederry, If I only had brain”.