Human being is the master of nature and fundamental difference between other creatures and a human being is the brain. Brain is most fascinating and complicated structure placed in a human body. It can produce emotion, much flexible to change itself and much powerful than any computer on earth. [Tweet “Interestingly, despite of its super function, human brain only consumes energy equal to a light bulb (20 watts).”]
In our daily life, we continuously observe different experiences, but we remained unaware of these experiences. Incredibly, brain is an organ of human body, which can identify its own being. It’s the incredible capacity of mind that we can feel ourselves, interact with other human beings and produce machines and devices. Human brain is a place of personality and emotion. It gives us uniqueness, ability to empathize, remember the past and power to think about the future. In its proper functioning, brain is a marvelous system and more proficient than the most powerful supercomputer of the world.
[Tweet “Da Vinci’s Mona Lisa, Beethoven’s symphony and Wright brother’s airplane, all were brain’s excellence.”] Through its cognitive power, brain integrates and synthesizes data from environment and produced flawless experience of awareness. This ends in a marvelous sonata of ideas, emotions, beliefs and experiences. But, despite of its excellence and qualities, it is so fragile that we could lose it in a blink of an eye.
Let’s take an overview of human brain module.
Magnificent Brain Structure.
A normal human brain is almost 1.3 to 1.4 Kilogram (around 3 pounds), which makes about 2% of body weight. As per study conducted in 1994, with age-growth, brain weight declines about 2.7-grams and 2.2-grams in males and females, respectively. Even it makes a tiny amount of human body weight, it requires much nutrients. 15% of blood pumped by heart goes to brain. [Tweet “Because of its high metabolic needs, brain consumes 15% of total body sugar and 20% of body’s oxygen.”] An average human brain consists upon about 100-billion neurons and for each neuron there are almost 10 glial cells (supporting-cells). It means normal human brain contains approximately 1-trillion cells. Interestingly, each neuron makes hundreds and thousands links with other neurons, which makes it incredibly complex entity in the whole universe.
Cerebrospinal fluid (CSF).
Human brain has a default system which removes toxic waste and nurtures the brain. CSF (Cerebrospinal fluid) is a fluid that found in CNS (Central Nervous System), including spinal cord and brain. This fluid produced from choroid plexus which exists in brain cavities called “ventricles”. It is, also, produced by cells which make-up coatings of ventricles i.e. ependymal cells. After its production, it moves downwards all the way towards the bottom of brain. In this process it moves through “subarachnoid space”, situated right above the brain and spinal cord.
Major function of CSF is to pillow the brain inside the skull and it plays a role of shock absorber for CNS. CSF also helps to remove toxins from brain and circulates required nutrients that are sifted from bloodstream. CSF produced at regular rate of 0.3 mL per minute. Major reason in Alzheimer’s disease is the less CSF production, and it plays a contributing role in damaging-effects of Alzheimer’s disease. CSF helps nourishment of brain cells and maintain optimal atmosphere for proper performance of brain cells. Additionally, it transports hormones from the body to particular parts of brain. It plays as an interface between brain and body as vital controller of normality inside the brain.
Brain’s role in nervous system
Human body’s nervous system is very complicate and significant. It may call as “Key control system” in the body and linked with every part of mental and physical health.
The primary and most eminent kind of nerve cells are neurons. These neurons broadcast biochemical and electrical signaled through whole body. Our thoughts, behaviors and emotions, all can be wrecked in three steps i.e. sensation, reaction and integration carried-out by neurons.
Second kind of cells is glial cells (derived from word glue) that are almost more than 10-times than neurons. Glial-cells can be further divided into few categories, with important functions like structural and physical support for nervous system. It also plays role in maintenance of environment inside the brain, facilitation in their actions and protection of neurons. All glial cells and neurons are structured in two separate parts which are supportive to each other.
Central nervous system, which includes our brain and spinal cord, is the key control hub of our body. However, rest of nervous system includes all nerves extending out from the spine and the brain. This peripheral nervous system allows communication between main control hub and rest of the body.
Building Blocks of Human Brain.
Human brain is fully talented to accomplish achievements through flawless working in a fabulously organized way. The least functional unit inside the brain is on the order of a single neuron which is called neurons. These neurons are basic building block of extensive array of trail that makes the brain able to function. Basic building block of any part of human body is cell. Human body comprises almost 200 different cells, and each cell is specific for a particular function as per body need. As an example, look at kidney cell which is superficially devised to extract essential nutrients and electrolytes that body needs. Similarly, specific function of heart cell is to contract so that blood may pump throughout body.
Every cell has distinctive characteristic and structure (organelles) which facilitate the role of that very cell. There are two main cellular categorization in brain i.e. glia and neurons. Interestingly, in diameter a neuron vary from 4 to 100 microns, but it can convey signals with the speed of 200-miles/ hour. Neurons are structured cells known as “soma” which consist vital organelles like ribosomes, nucleus and rough endoplasmic reticulum etc.
Mainly neurons come in three main forms and much different volumes. Apart from their size and volume, their general function is to sense, and assimilates and proceeds with that sense. Our organs and muscles react to our sensations as per messages communicated by them. These neurons are capable to receive indications and signals from other neurons mainly through cellular extensions i.e. “dendrites”. It can further convey signals vide specialized expansion called as “axon”. The end-point of axon is called as synaptic bouton and generally makes a link (synapse) with dendrite of other neuron.
Function of glial cells.
Notwithstanding, that neurons are foundation of neural links, yet supporting cells play equally vital role in normal brain functioning. Earlier these supporting cells (glial) were considered least role player. But with recent study as well as more un-earthed discoveries, it is clear that how much glial cells are important. These cells, not only protects brain from toxins but also helps to remove damaging stuff from brain. It ensures a healthy environment for neurons inside the brain. Moreover, it functions to promote the formation of new links inside the brain and helps the human brain to revive itself.
These cells are responsible for immediate response inside the brain against disease conditions. They also modulate brain’s capacity to recover from strokes, trauma and infections etc. Glial don’t perform neural function rather they protect and nourishes the neurons. They outnumber neurons 10 to 1 with the capacity of regeneration, neurons have no such capacity of renewal. That’s the reason you may have heard that wrong statement “you can use only 10% of your brain”. [Tweet “Reason behind this false-statement is out of total cells, 10% if neurons and rest of 90% is glial cells. Actually, everybody uses 100% brain every time, as whole brain is always active.”]Even while sleeping it combines new sensory stimuli with pre-existing information and maintains physical and chemical condition throughout the body.
Flexibility of human brain.
Human brain is very much malleable and pliable, that it can dynamically modify by changing circuits and synthesize new connections. Because of this capacity it protects itself and allows adapting environment. Although, flexibility is the regular part of brain’s function, but it’s very helpful for repairing in case of brain damage. For example, in case of brain stroke (which is equal to heart attack) brain marvelously protects and repairs itself.
Flexibility is extra-ordinary feature which is exceptional to brain and organs like liver. It gives ability to recover from traumas, learn new skills and facts and very much critical for normal cognitive growth. Actually, (as per Muckli L., 2009) there are many cases of kids born with one hemisphere (half brain) could grow normally with no clear deictic. Reason behind brain’s ability to reprogram itself is that neurons are already programmed to perform specific tasks. They can also adjust their functions as per body’s need.
But the extent and level of such flexibility varies with passaging time. It is most in childhood but reduces with age. There may be different reasons behind this attenuation of flexibility of brain. Primarily it links with lessen number of neural stem cells which facilitate regeneration of normal cognitive functions of brain. That’s why neurological offense in elderly life can cause more hindrance than similar offense in early age of development. However, some argues that, elder patients lose brain tissues with the passage of time, with fewer tissues “reserved” for recovery.
Growth and development of human brain.
In order to unearth the secrets of basic neural networks, recently scientists have tried to turn up childhood brain development. Interestingly, a child’s brain is extraordinarily flexible but very susceptible towards poisonous substances such as drugs and alcohol. A child on his birth has abundant neurons mainly for connectivity. With the experience in his life, child’s neural trail starts to develop. However, surplus neurons which are not activated, destroys upon birth, and continuous to destroy till sexual maturity. We called this process “synaptic pruning” that improves efficiency of human brain by removing redundant neurons and reinforce important circuits.
Dense connectivity is resilient to brain damage.
Despite of such loss of neurons since birth, actual size of brain continues to increase till adulthood. This increase in size is intervened by increase in synaptic connectivity among neurons and myelination of neurons. This myelination initiates in 14th week of fetal development till the age of 25-years. Synaptic trimming is affected due to different environmental-factors and can influence its density and amount of neurons in an adult-brain. Degree of synaptic pruning can be influenced by Social integration, education, a motivating environment and other childhood exposures. That’s why a brain with thick connectivity is considered much flexible in diseases like Alzheimer’s (which destroys connections inside brain).
Organization of Human Brain.
Just like any other structured masterwork, human brain has a fabulous design, divided in four parts. These parts are frontal, parietal, temporal and occipital lobes, and each part has its unique function.
- Occipital lobe, located in the rearmost part of brain is responsible for our ability of sight.
- Temporal lobes, on the sides of brain are responsible for hearing and speaking senses.
- Frontal lobe is responsible for our thinking and future planning. It involves in spontaneity, problem solving, initiation, impulse control and social behavior.
- Parietal lobe plays role in processing sensory information regarding location of body parts and processing of language and mathematics.
However, these lobes don’t work alone, instead they are interconnected with each other and continuously communicating with each other. Such connections make us able to remember particular things. Like if you have tasted Durian fruit (smelliest fruit on earth), smelled or ate. All of these different sensory stimuli combine inside the brain to create single concept of “what Durian fruit is”. Thenceforward, whenever you think about Durian fruit, you may not remember each isolated sense, but imagine a perception of different aspects of durian fruit, collect them to create single unified experience. This ability of brain is due to combination of impressions with pre-existing experiences and memories.
Human brain has many other functional elements. Amongst other essential components, “Basal Ganglia” is very much important element also known as brain’s operational network. It’s also known as chief regulator of personality, emotion and memory. It has a vital element called “hippocampus”, where new memoirs are formed. You can say it’s a memory’s Holy Grail. It has been discovered that it plays big role in early signs of Alzheimer’s disease.
In a famous case of H.M (Henry Molaison), who had surgically removed his hippocampus in 1953. He had disease of epilepsy, and it surgeons thought, that the seizures were originated in hippocampus. Although he was cured, but now he could no longer form new memoirs. Interestingly, other memories which he had before surgery e.g. ability to trace a figure through pencil and motor-learning were intact. Even he could recall events took place before his surgery. Through this incident doctors came to know that hippocampus plays an important role in memory and learning. Most interestingly, this is the area that Alzheimer’s disease attacks first.
You can cross-check details from following references:
- Hartmann P, Ramseier A and Gudat F (1994) Normal weight of the brain in adults in relation to age, sex, body height and weight.
- Willie CK, Smith KJ. (2011) Fuelling the exercising brain: A regulatory quagmire for lactate metabolism.
- Book New Perspectives in Regeneration by Heber-Katz E, Stocum DL
- Bilateral visual ield maps in a patient with only one hemisphere. By Lars Muckli, Marcus J. Naumer, and Wolf Singer
- Book (Alzheimer’s disease decoded. The history, present, and future of Alzheimer’s disease) by Chen, Jefferson et al.