Tuesday, July 8, 2008

Just Scratching the Surface

Is there any reason to learn the intricate design and function of our brains? If your studying to be a brain surgeon...yes. The rest of us?...... Well, we know we have a brain, we hope it is healthy and working properly. Unless faced with tragedy, like a brain injury (or addiction) most of us unknowingly take the human brain for granted. Sure, we all know how amazing and complex the brain is. We know our brains think and learn, they tell us to feel happy or sad. We also understand that when we touch something hot it is our brain that tells us to remove our finger quickly. It also tells us not to do it again.

I am no more the expert in brain function today than I was 2 years ago although I do have a much better understanding. Our brains are so complex and so completely awesome, it would be wrong of me to even try to explain in any great lengths. To be honest, I don't think I could without sounding like a complete idiot. So I decided that it was best to keep it as simple as I could, and even that was not easy.

Some day when you have a 'few weeks' with nothing to do, you may find it interesting to look into any of the many informative websites educating us on how our brains work. It is staggering information. I could not help but feel like part of my brain was bruised as I read and struggled through the intense information and details of the human brain.

Here is my humble attempt to relay to you only a fraction of what I read about basic brain anatomy and function.

This awesome organ, weighing in at a whopping three pounds, is likened to not just one, but 'millions of little computers' that come together as a whole, in perfect unison. It controls every single thing about us including, but not limited to, intelligence, memory, personality, emotion, speech, and ability to feel and move. Motor control, visual and auditory processing, voluntary and involuntary functions, thirst, appetite, sleep patterns, breathing, heart rate, blood pressure, swallowing, digestion, and blinking. It enables us to interpret and respond to every single thing we experience.

The brain is divided into three basic units:
The forebrain is the largest and most developed part of the human brain. It consists primarily of the cerebrum, the source of intellectual activities. It holds your memories, allows you to think and plan, imagine, recognize people, read and play games. The cerebrum is split into two halves. The two cerebral hemispheres communicate with each other through a tract of nerve fibers. Each hemisphere has specific functions. The surface of each hemisphere is made up of grey matter known as the cerebral cortex and is responsible for thinking, perceiving, and producing and understanding language.
The midbrain controls some reflex actions and is part of the circuit involved in the control of eye movements and other voluntary movements
The hindbrain includes the upper part of the spinal cord, the brain stem and the cerebellum. It controls vital functions such as respiration and heart rate. The cerebellum coordinates movement and is involved in learned movements like playing a piano.

The inner brain, lies deep within the brain controlling your emotions and memories. This is known as the limbic system.The limbic system uses current situations and memories to generate your emotional responses particularly those associated with our survival. It is involved in many of our emotions and motivations, such as fear and anger. The limbic system also regulates feelings of pleasure. If something is pleasurable or rewarding, you want to do it again. This is also referred to as the Reward System. Limbic system structures called the amygdala and hippocampus are also involved in memory. One of the reasons that drugs of abuse can exert such powerful control over our behavior is that they act directly on the brainstem and limbic structures, which can override the cortex in controlling our behavior and eliminate the most human part of our brain from its role in controlling our behavior.

The central nervous system is divided into two parts: the brain and the spinal cord
The peripheral nervous system is divided into two major parts: the somatic nervous system and the autonomic nervous system. It allows our brains to communicate with the rest of our bodies by way of a very complicated highway system. Using the example of the hot stove, when our finger touches the heat, this sensation (or message) travels to our brain at a speeds up to 268 mph and tells us to pull our finger away.

The brain consists of about 100 billion cells called neurons. Each of the billions of neurons produce chemicals that trigger or "talk" to other neurons. These chemicals are called neurotransmitters that send messages from one nerve cell to another binding to receptors on the neuron receiving the message. The place where a signal passes from one neuron to another is called synapse.(Meaning to fasten together)When the transmitter hits the receptor, the receptor will change shape causing changes inside the nerve ending. This then sets off an electrical message onto the next brain cell. This sequence continues until the effect occurs.

The three major categories of substances that act as neurotransmitters are:
Amino Acids (primarily glutamic acid, GABA, aspartic acid and glycine) Amino Acids are the building blocks of proteins, the precursor to neurotransmitters and balance brain chemistry.
Peptides (vasopressin, somatostatin, neurotensin, and many more) Peptides are short polymers formed from the linking of amino acids in a defined order. The link between one amino acid residue and the next is known as an amide bond or a peptide bond.
Monoamines (norepinephrine, dopamine and serotonin, acetylcholine and others)
Serotonin is known as the "feel good" neurotransmitter. It plays an important role in the regulation of mood. Low levels of serotonin can cause excessive feelings of sadness and anxiety.
Dopamine and norepinephrine affects brain processes that control movement, emotional response, and ability to experience pleasure and pain. Controls heart and blood pressure, sleep, arousal and drive. When the brain does not produce enough dopamine or norepinephrine, you feel tired, unmotivated and foggy.

There are two kinds of neurotransmitters –
Excitatory transmitters stimulate the brain.
Inhibitory transmitters calm the brain and balance mood. They are easily depleted when the excitatory neurotransmitters are overactive.

Endorphins. A group of ten neurotransmitters that activate opiate receptors. Endorphins are composed of chains of amino acids. Since the discovery of the endorphins in 1975, scientists have theorized that these neurotransmitters are released when the body encounters stress. After a physical injury, endorphins activate opiate receptors and produce an analgesic effect, alleviating severe pain. During times of emotional stress, endorphins are released in the limbic system of the brain and produce a euphoria that lessens anxiety and melancholy The word endorphin comes from a combination of the word Endogenous, meaning 'growing within' and morphine.

In 1973, scientists discovered that the brain had receptors for opiates. (Places on neurons that recognize opiates). Two years later, scientists discovered the brain produced its own opiates known as "endorphins." Endorphins are always in the brain, but they are released in larger amounts when people are in pain or under stress. Each receptor recognized and only allow specific transmitters to bind to them similar to the way only 'one' key works in a specific lock.

Last but not least in this section, I found this next bit of information completely amazing:

By a process known as 're-uptake' (and others) our brains recycle and regulate normal levels of neurotransmitters by reabsorbing them once they have performed their function of transmitting the neural impulse.

Incredible stuff for something that only weighs 3 pounds..... and that my friends, is only scratching the surface.

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